Royal Enfield Interceptor Owners

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Front Fork Question (Thu Dec 4, 2003 5:13 am)

From: "todd_johnson30"

I have been looking at many photos of Inters , & havent seen one with the same forks , or long chrome covers/headlight mounts , i'm wondering if the front end may have been swapped out at some point, does anyone know if this was an option on series 1 exports? it also has no provision for fork gaiters , & no exposed fork tube

Todd,

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which series are you speaking of? IIRC The Series 1 had various steel shrouds, and possibly gaiters, the Series 1a had gaiters and the Series 2 had Norton Road holder forks which you can ID by the lower not having the RE off set axle mounting.

Another thing to keep in mind is that it is easy to bolt up a front end from a Suzuki, or Kawasaki, or other make of bike. There is a guy in northern Illinois who has an Enfield twin with a Kawasaki front end with a disc brake. That seems tempting sometimes.

I am thinking about sending my Series 1a front wheel to Vintage Brake in LA. The shipping costs are considerable, but I know Mike Morse is among the best at getting maximum performance from a drum brake. IIRC someone had him do a brake and reported enough stopping power to make the frame bottom out on the front fender. Has anyone else used Vintage Brake to do a Series 1a front drum?

Thanks
RickL
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Rick is right about the other forks that can slot into the Inter's frame.

A while back I wrote it up in some detail, but the conversion I have the most experience with, is the 1973 - 77 Suzuki GT750 front end. You use the entire Suzuki front end, complete with its triple clamps and upper & lower bearing races (without mods). You retain the Enfield bearing races in the frame, because they line up perfectly with the Suzuki parts.

The only mod required is to the Enfield races in the frame: they need to be opened up to clear the Suz steering stem: seems to me 1.125" dia, IIRC. Bear in mind the races are extremely hard, so the ID will need to be ground to size in a lathe, using a tool post grinder.

The GT750 front end has twin disks that are designed to stop a 550 lb machine. They work very well on the Inter, and are well-behaved: I've ridden quite extensively a Series 1 modded by me 15 years ago, so I speak from experience.

The other disk brake conversion I I'm familiar with is using a single Suzuki GSX/R 1100 floating disk (ca, 1986- 1989, about 12" dia), with a Suz 4 piston caliper from a 1986 vintage GSX/R. The 1986/7 disks are easier to work with because they have shallower dish, but they are getting extremely difficult to find in good condition. The 1988/9 disks require a bit more art in making a hub adapter, but work well. I've used both types of disk successfully.

I would avoid the later calipers, because they are wide and would foul the spokes. As it is, with the 1986 style caliper, you have to dismantle it, mill off the external fluid bridge between the two piston bores. You then TIG weld a cover over the exposed area, while making sure the two bores can share fluid ... hard to explain in words, but it will be obvious once you see an actual caliper.

The above mod I did to the Roadholder forks on a 1975 Commando, and after 8 years of road use, I can attest that a single disk behaves very well. Of course, the Roadholders were originally equipped with a Lockheed disk, so the mod was somewhat straightforward, but there's no reason you couldn't use the GT750 forks and wheel, and adapt the later disk & caliper to that hub.

I've never dealt with Vintage Brake, but I've heard good reviews about them. I personally find the original drum brakes on my Series 1a quite acceptable, though I admit to using the rear brake considerably more than I would on a modern rocket bike. When I restored my Inter, I bought a new twin leading shoe brake as would be fitted to an Indian 'Boolet', but didn't get around to the conversion prior to the start of riding season. Having had this Inter on the road for 4 years, I don't feel much need to do the conversion.

... gREgg

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This is great info. Do you know if the Suzuki forks or any other that might work on my 66 Matchless G15CSR? It had the roadholder forks but with a different shaft length if I'm correct. Bobby B Calgary AB

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Sorry Bobby, but it may not be a drop-in job like it was on the Inter.

I say this because the older Nortons used 5/16" balls and rather large races ... (though they went to standard 62xx series ball races in the later Commandos). Whether your Matchless used the same races as the older Roadholder forks, I can not tell. I suspect however, you can easily make up adapters to fit taper roller bearings into the frame headstock.

Also, the GT750 forks are very forgiving, because you can slide the stanchion tubes up through the upper triple clamp to adjust the ride height. They are probably well worth investigating.

The other option I've forgotten to mention is the 1972 GT750 front end ... which may be better suited to people who like the looks of a drum brake in a spoked wheel. In 1972 (which was the only year for it), Suzuki produced a two-sided, 4-leading shoe 8" brake, in a fork similar to the later machines. In case anyone is interested in one, I have a complete front end of this type with the 4-leading shoe brake, which I am no longer planning to use.

.. gREgg

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Thanks. This interests me gratly as I have had many GT 750's as well as the 75 RE5. I always liked the front end on these bikes. The drum version would more standard looking than the disc model. I might check with my local wreckers.
Thanks Bobby B

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Various finishes (Sat Dec 6, 2003 4:38 am)

From: "todd_johnson30"

with all of the steel bolts on an Inter, what is the correct finish? my 68'MK1a is in many little pieces , & I am experimenting with raw cast iron lok paint & high heat aluminum paint for car brake calibers , any suggestions from the group?.........Thanks Todd

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Rear Hub Discussion (Tue Dec 9, 2003 5:43 am)

From: "bantam1967"

Hi all,
Thank you for your help on my question on 11 november 03, (engine id). Got another question;got the wrong rear hub,a Matchless, is it smart to replace it for an India Enfield hub? Besides,my frame number is X998.
Fred.

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What year and model are you speaking of here? I have a '55 700 twin that had a strange rear hub. It was the stock hub, some RE specialists told me it was a Velocette or Matchless hub. You can see a picture of this bike, showing the hub in Ray Bacon's book.

PS. I am consolidating all of my RE parts. We plan on sorting them according to the too many projects I have. I will have a list of parts to trade for items I need for the active projects. I may offer some of the projects for trade as well. I hope to have this together around the new year. I will jump at a 350 motor our good bottom end.

RickL

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Hello Rick and other users of this site. Risk you had the right question: what bike and type. I ts an Interceptor model 1966,the question is, which rear hub,qd type, I can use.The original rear hub all complete, is out of stock at Hitchcock. Will an India Bullet hub suit?
Fred.

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Oil Relief Paths (Mon Dec 15, 2003 5:57 am)

From: "paulus46"

Relief paths?

The oilpipe to the head on the series 2 first provides the inlet, and then continues to the exhaust. As the exhaust side gets the most hot I thought it a clever idea to restrict the oilway to the inletside a bit.... bringing back the drilling through the banjo bolt... from 2.5 mm to 1.5 mm. I tried to check the results with a running engine, but didnt see much but noise and darkness.

So I did it the other way using an electrical oil pump. To my surprise there was hardly any oil coming out on either side. The restriction here is apparently not in the banjo either with 2.5 mm or 1.5 mm.

To find out why I took the rockers out. The idea is that the oil flows through the hollow spindle.. comes out of the spindle through a 2.5 mm hole halfway, flows through a half moon cut-out in the outside of the spindle. Continues through a groove on the inside of the rocker that leads the oil to the 0.5 drilling through the rocker arm and then sprays on the head.

Now I remember a mail from Ole in the knowledge base with advices from the mister Egli about the Interceptor oil system. Advice nr 5 says: 'grind relief paths in the rocker gear to allow generous oil through flow at this point'.

Now, my question is.. what does the master mean? I suppose the oiling on the head is not based on oil pressure, but on the rockers throwing out the oil. So I dont think it is a good idea to open up the drillings through the rocker arms. What I can imagine is the groove inside the rocker, and the half moon cut out in the spindle, as these are very restrictive..?
Paulus

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Hi Paulus

REgarding, getting a more even pressure to the rockers or a bit more to the exhaust. See also The second section of gREgg's input in the Knowledge base on oil following that one about "Trochoidal - Pump", (direct link is below), which covers an approach to not have the feed in series but a branch going diretly to the inlet rocker feeder and another directly to the exhaust rocker, as on the older 700's.
REgards
Royal

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Paulus,

Interesting observations you have conducted !
Your observation that the small "jets" in the rocker arms act as a kind of centrifugal pump is also interesting.

( The fact that the cetrifugal pump action generated by the crankshaft constantly saves a lot of SII's from total seizure is not something you like to think about too often !)

The advice given by Mr Egli about opening up flowpaths in the rocker system cannot be separated from the other peice of advice he offered - namely : " Increase oilflow ( - /pressure ) to the tops !" His idea of "cascading" the tops with oil can never be acheived by the above centrifugal pump-action.

This function can only be regarded as an emergency lubrication system, that - when relevant - will be feeding through the 0,5 mm emergengy hole in the otherwise closed relief valve !

Mr Eglis recommendation about increasing top-oilflow is not possible with the hopeless pump of the SII. We know that - when the going gets tough ( hot engine, high revs ) - the SII oilpump simply gives up !! ( Sorry to disregard the dutch windkettle system, but it has not been possible to reproduce good results.) Directing more of a non-existent pressure/flow to the tops doesn't make much sense !?

So you are right, Paulus : There's no point in opening up flowpaths in the rocker-system if it's the only modification you intend to perform.

Best REgards, Ole

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Hi Again Paulus and All.
Ole Eriksen has sent in a great option to the short comings of the
Interceptor Oilpump, possibly the best one so far, which I just had
to put up asap, give the recent discussion.
On our web site: select
Pit-Knowledgebase-Engine-Oilproblem with Cylinder Head-Using Honda
Oilpump
or just use the direct link
http://www.ozemate.com/interceptor/kboil2a.htm#alt28

I will catch up in a couple of days with some of the rest of
december updates.
Have a Great and Merry Christmas and Happy New Year.
REgards
Royal

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Ole
I think this is a very proactive initiative. The interest and discussions on this oil cavitation issue alone illustrates that it is probably one major issue with this machine, when ridden hard.

Regarding the action point. Yes I have put up the drawings and the details you forwarded on our web site (with direct web address noted). Regarding Chinese connection I do have an Australian friend currently in the Quang Dong district.

I don't know about the rest of you guys, but I don't necessarily want to wring every cheep cent out of the effort. For accessibility and ongoing support

I don't mind to pay that little bit extra. Ole, preliminary, put me down for one unit for now. With the rest of guys interested to pursue this part we should get an indication of the interest so you can get a number of units to be produced in order to get the quote. Once you have the quote, Based on the quoted price, we should get a final order by those interested. Then I suggest that we look at making at least a part payment (depending on the cost making the adapted bits).

If we have the interest, I might have a chat with Hitchcock to look at sponsoring the project, by giving us close to cost prices on parts necessary. They might even be interested in having a couple of adaptor units made themselves.
Some owners might want to go ahead using new parts, retaining their original parts (spindle etc).

Personally I'll probably use parts from my spare engine once I've had them checked over. Those that commit to the final order probably need contact details to BikeBandit for initially buying the pump.

Regarding the alternatives, I propose approaches like,
1. Consulting machine shops dealing with oilpump modifications
(preferably for classic motorbikes)
2. Discussing the options in this group.
3. Prototyping, if someone has the means to do so.
4. Studying other contemporary similar engines, through available
sources on the net.

Not having fully digested the merits and options listed in your e- mail, I kind of feel comfortable with Madmax's option.
REgards
Royal

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Ole
Definatly count me in for a pump conversion kit. Wonderful work. If
you want my humble opinion I would like to see the crank snout
retained in an unmodified state. Well done Ole nice work.
Rick Fisher

Ole,

Good work! As is happens, I am having some CNC work done for work, and the shop that's doing it is first class: the devices we're having made have tolerances of 20 microns.

Why not send me the IGES files, and I'll see if I can get a quote from them for 25 sets of the parts, or something like that.

BTW, I must admit that you've got me thinking about using two of them - one feed and one return - on my Series 1A.

.. Gregg

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Royal, Rick (Fisher) and Gregg,

Thanks for your kind acknowledgments, it's good to hear that others want to join the project !
Gregg, I will send you the IGES files as soon as I'm back at work !
( They need to be supported by work drawings that include tolrerances, but for a first estimate they should do.)

Ole

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Ole,

BTW, while I was looking at the parts of your pump design the other day, a worthwhile mod occurred to me. The new semi-circular part that that carries the O-rings could well be machined from the same plate that now bolts onto the timing cover. Made that way, the new part that fits into the pump-disk cavity would not be free to rotate and possibly block the oil transfer holes.

The other thing that's been nagging me is the possibility of having too much flow to the top end. I know Lotus twin cam engines quite well, and one problem they suffered from when fitted with a high-capacity oil pump was the real problem of flooding the head, and not having quick enough drains to the sump. The pump solved oil pressure problems but created another! This was solved in practice by adding flow restrictors to the oil galleries that fed the Lotus top end, and that may prove necessary with the SII.

The other thing that's nagging me about fitting these pumps to the dry sump S1A engine is balancing the feed and return pump rates. I doubt the stock scavenge pump would have enough capacity, and a second Honda pump would be overkill. The only thing I could come up with was reducing the capacity of the feed Honda pump somewhat by thinning the rotor assembly ... that might kill the over-oiling problem as well.

All this said, I'm not having oil pump problems with my stock S1A, but there's always room for improvement, and I suspect the top end would be a lot happier with better lubing.

.. gREgg

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Gregg,

Your first point : My original design was a 1-peice-part as you suggest, but following good advice from Bill (Madmax), I changed it to the two-peice design. The thing can't rotate ! It is locked by the Adapter.

I don't think we have to worry about too much about overflowing the tops ! After all, the flowrate of the new pump is not that impressive compared to modern engines. Also the drain paths down past the lifter-guides are easy to augment should it prove necessary.

The overflow holes from the camshaft pockets are generous and could also easily be augmented. It might, however, be a good idea to fit seals at the top of the valve stems !?
No comments to the IA- issues since I don't know that engine.

Ole

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Gregg,

I don't think overflowing will be a problem either. There is no overflowing when the engine is cold and the RE pump is working really well. Once the oil gets hot and thin, I don't believe it will have any trouble draining out of the heads. If we greatly misjudge the volume of the pump and have excessive oil going to the rockers, it will be really easy to put a restriction in the fitting where the oil feed tube connects to the crankcase.

Madmax

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Hi Guys

with reference to previous discussions about extra oil pressure etc.

The are two screws I haven't had to move on my 70 interceptor. They are mentioned in the extract below. I believe they adjust the oil pressure to the big end and directly or indirectly to the head. I might be missing something here, but increasing the pumping capacity, might it not interfere with the oil pressure that these valves are trying to control. Extract from the manual below.

Regards
Royal

There are two pressure relief valves in the oiling system, both are located at the top of the crankcase, behind the right hand cylinder barrel. (See Fig. 11). The right hand screw holds a 5/16 dia. ball and spring in position, forming the main relief valve holding a pressure of 60 lbs./sq.in. in the oil supply line to the big-ends. It is important that the correct washer is used under the head of the screw, a thinner washer or no washer at all will give a higher pressure than intended.

Too high a pressure in this part of the system could cause damage to the crankshaft seal in the timing cover and leakage at this point will reduce the amount of oil passing the main release valve. This could cause oil starvation at the rockers and lead to excessive wear of cams and tappets and poor lubrication of camshaft bearings.

If the pressure in the main system is too low, the amount of oil reaching the big-ends will be reduced. The second screw forms a pressure relief valve for the oil supply to the overhead rockers. The unit is pre-set at the Works to release at 10-15 lbs./sq.in. and cannot be adjusted.

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Hi Royal and all Interceptor riders,

Here's my take on the SII relief valves. The primary relief valve (PRV) (60 psi) really preforms no useful function after the oil has warmed up because the pressure in the system is less than 60 psi. The only function of the PRV is to protect the crankshaft seal from being blown out on start up when the oil is cold and the pressure can be 80 psi or more. After the oil is warm, the system pressure is less than 60 psi so the PRV is closed all the time and the only oil that gets to the heads comes from leakage around the PRV ball. Based on this analysis, I can't see any reason to adjust it.

The secondary relief valve (SRV) (10 psi) vents oil in the passage to the heads back to the crank case. My experments have shown that this valve is always partially open because the system pressure is above 10 psi so some oil is always going back into the crankcase. The only reason to keep this valve that I can see is that it is the only relief for the high oil pressure during start up. Obviously it would be better if this valve were closed because it would improve the oil pressure a little bit. I tried closing it off and got about a 5 psi improvement in oil pressure but I had to start and stop the engine 3 or 4 times to warm up the oil without going much over 80 psi.

I have pretty much given up on making any improvements with the existing relief valves. If we can make a better oil pump, it won't matter anyway.

Happy Holidays to all,
Madmax
Houston, Texas

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Good going, Madmax !

If your last statement can be interpreted as you being a serious candidate to the "New Pump"project, we can now count 6 interested parties :

Royal
Rick Fisher
Gregg
Charlie
Madmax
Ole

Please everybody, come forward now if you are interested !! Don't count on there being "a second time round". Although the pump will be a prototype, there is not much that can go wrong with those cnc-machined parts. Any necesary minor adjusments will of course be carried out on the first assembly and implemented on the rest.

Best Christmas and New Years wishes to all !
Ole

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Ole, This is a giant step for mankind... that is: if you are the Interceptor owning part of mankind) I am surely interested in this modification!
Paulus

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Greetings all, and best wishes for peaceful holidays,
Like Gregg, I have a 1A, which does not diminish interest in the oil pump work, but which introduces further variables. If we're in fact standing up to be counted - yes, please count me in . . . but as importantly, thanks everybody for all your sharing. (quiet)George in Vermont

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Timing chain tensioner. (Wed Dec 17, 2003 2:42 pm)

From: "G.R. Kricorissian"

While we're discussing interesting mods to our engines, it's always occurred to me that a dynamic tensioner for the timing chain would be a good thing, and in addition to helping keep valve timing under better control, would help the engine run quieter.

I know that such aftermarket tensioners are popular in the Norton Commando world (adapted from a Mazda tensioner), and the idea was even taken to heart by the Norton factory in the design of the primary chain tensioner of their 850 MKIII.

The primary's slipper tensioner works pretty well, but I keep thinking a hydraulic timing chain tensioner is something I should think more about this winter ... has anyone given it any thought?

.. gREgg

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Very interesting Gregg !!

Please give it some more thought. Not only will the engine run quieter, but it will also have a more stable ignition timing at slow cruising speeds ? I have a strong notion that some of the roughness that occurs in the zone between engine pulling and breaking ( -don't know the expression for it in english !?) not only stems from the transmission but also comes form "flutter" in the timing /ignition chain ??

Ole

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Rick,

REgarding tensioners, I was not advocating a pressure-fed style as used by Porsche from 1984-on in the 911, but rather a passive style as they'd used previously, and also by Norton from 1975 on the primary chain. These types collect oil from splash, and rely on the natural pumping action of a chain that's too loose. There is often a relief valve to prevent over-tensioning. The pressure-fed Porsche tensioners work very well and are bullet-proof, but in my opinion are over-kill on a bike.

The Commando tensioners I've seen are the Kork and the RMA, and neither of them are pressure-fed. The Kork is a modified Mazda tensioner, while the RMA is a sliding wedge design, tensioned by a coil spring. Both are reported to work well, though the RMA style has been known to over-tension on occasion.

So, though no one can deny the importance of a top-notch lubrication system, it is not a pre-requisite for a dynamic chain tensioner.

.. gREgg

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Oil drain back & tensioner issues. (Wed Dec 17, 2003 5:21 pm)

From: Rick F

Gregg with respect to your concerns on not sufficient area to allow for oil to drain back to the sump when a larger oil pump is fitted the drain back holes for each valve pocket is a whopping 1/2" in diameter. I can only speak for Series II's here as I have no experience with Series I's but didn't they use the same head castings?

As for the dynamic cam chain tensioner the Norton tensioner is a hydraulic one (at least the one I saw a demonstration on at the Norton Ralley was) and the first order of business would be to have an oil pump with enough pressure to operate said tensioner.

This forum has had numerious submissions where members have fitted oil pressure guages to Interceptors only to watch in horror as the oil pressure drops to or very near zero. IMHO the first order of business is to get the oil pressure problem solved and then go from there.

I do like your idea (if do-able) of keeping the cases as stock appearing as feasable (that's of course if the size of the Honda pump used in Ole's modification will allow for it). All feedback + or - welcome.
Rick

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Rick

I didn't mean to imply that there would be a problem, just to caution what might happen, in light of other who have experienced it.

Though the Inter's heads have large holes for drainage as you describe, those also contain the push rods, which limit the cross-sectional area. Then, the returning oil flows down these holes until it meets the cam followers, which effectively block the return path, except for a small slot cut in the OD of the guide. Here, it collects in the camshaft tunnels, where it bathes the cams. (BTW, this is one of many ways in which the Enfield twin design is far superior to other Brit twins. Nortons, for example suffer from chronic cam problems because they overlooked this area.

Honda also re-invented this problem many times with several engines over the years).

From there, the oil is allowed to drain via an overflow into the timing chest in the case of the SII, and in the case of the inlet side of the S1, drain back to the oil tank.

So, you can see, despite the generous head drain holes, the path back to the bottom has several constrictions, and the possibility exists to exceed the return flow capacity if the feed increases greatly. Granted, the return path has several reservoir area in the vertical plane, but the greatest risk to flooding is during high speed touring.

Again, Norton discovered the perils of inadequate return flow with the Commando during the early 70's when they modded the engine's return path (for the worse), and had huge problems with cavitation and attendant wet sumping at speed when the bikes were sold in North America. Like everything in design engineering, the devil is in the details.

Looking forward to more details on Ole's pump design!

... gREgg

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Recently finished Special TT Interceptor (Sun, 21 December 2003)

Here are two pictures of my recently finished Special TT Interceptor.
I bought it last year from Steve in south England.He got the bike in 1988 from California.

Now it has its original condition. I have a lot of fun with this great bike.

Maybe you can take the pictures to your galler and mark it at the worldmap.
Have a merry christmas and a happy new year!

Greetings,
Christoph

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Fibreglas petrol tanks (Sun Dec 21, 2003 4:00 pm)

From: "Chris Overton"

I have been offered a fibreglas petrol tank but know nothing about them except
it is claimed to be 4 gallon UK spec. What is the experience out there with
them? Do they last? I believe the resin in 'glass tanks on Norton Commandos
cannot withstand modern gasolines in North America. Are these the same?
Chris Overton Rossland BC Canada
1B 1734

Just a thought and don't know if it would work Chris but if the fiberglass
won't stand up to modern gas why don't you "creame" it and that would
isolate the fiberglass from the fuel??
R Fisher

Hi Chris,
One of the guys in our local CVMGroup had just this problem with the
glassfibre tank on his 70 Commando. As Rick mentioned, the cure was to
apply a creme sealer. That was several years ago and I think it did the
trick.
Don in Niagara ...1B1530

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Spedometer Ratio - Anyone?. (Mon Dec 22, 2003 8:21 pm)

From: "Royal"

Stephen Hill writes:
Hi Royal,

I was wondering if you know what the correct ratio for Series II Interceptor speedo drive is? The one on my bike is a 2:1 but it is stripped, and I have a feeling it is not correct anyway. Appreciate any help you can provide.

Stephen Hill

Regards
Royal

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Stephen/Royal
The speedo on mine is:... SSM 3001/00A 1600 and the speedo drive box is
2:1. The way I understand it, if the speedo is a 1600 ratio it matches to a 2:1
drive box. If the speedo is a 1000 it matches to the 1.75:1 drivebox. Correct??

Today the weatherman is calling for +6C. Lots of salt/sand mix on the roads but the snow is gone and I think the Inter is going to get some excercise!
Merry Christmas.
Don in Niagara

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Don,

I believe the alternate gearbox ratio is 15/12, or sometimes written as
1.75:1.

gREgg

Oops!

I meant to correct the '1.75:1' as it appears below, to '1.25:1'.

.. gREgg

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gREgg,
Yup that's it. Pulled one out of a box in the shed and that's what it said. Should have looked first and typed later!
Was sunny and +11C or 51F yesterday! The S2 took 6 kicks to start. It doesn't have any chokes in the Amals so I had to nurse it with the primers for a few seconds. Also didn't bother putting the battery in. We took a tour down thru Chippawa and by the Falls. That's a real good day around here this near Christmas! They're talking snow on Christmas Eve.
Have a Merryone everybody!
Don in Niagara ... 1B1530

 

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Crash followup (Tue Dec 23, 2003 12:43 am)

From: "Royal"

Hi all. I did mention that I'd wrap it up and give you all an account of the motorcycle accident I had the last of May. http://www.ozemate.com/crash There have been many that have e-mailed me. I haven't answered all the questions before, not even to myself.

I have had to visit the scene and do some analysing, and believe there can be some thoughts worth sharing on the event. You might be interested in how it happened and the conclusion.

For most accidents of this nature there is only silence left from the bikers point of view, and people who weren't there draw their own conclusions. If you have had the fortune to live through an accident yourself, as I said in a previous post, please do share it directly to me (via the web site feedback), because I'll take this as a first step in sharing accident information for the benefits of all. It will however not be part of our interceptor discussions or the interceptor web site.

Thanks for all the great input and discussions.
Merry Christmas and a Happy New Year to you all.
Royal

(Strange crash coincidence)
Hi Royal. I was just rereading your story of your accident on the website, as I had really just scanned it before for the more meaningful parts that might relate to my own accident, this time I went back for more detail.

Let me say that if you had your wreck in the remote area I had mine you wouldnt be around to tell of it, you would have bled to death..I was on the road for twenty minutes before the ambulance got there, and I was twenty + miles to the nearest hospital, plus there were no trained paramedics on board to give me any blood..no air flights and the ambulance people were part time, almost volunteers..
I too had the failing blood pressure and required the abdomen opening, but I didnt have your massive internal damage,

I just had no blood left..my guts were intact but my body was not.. my left wrist was broken and part of my left leg was denuded of flesh, it having gone into the wheel well of the truck as it skimmed by, tearing some of the fender off..

Oddly enough too if I had been wearing the same leggings you had on I might have my leg now, as It was only broken in two places, each bone in the lower leg once, but I contracted gangrene in the soft tissue, and had to have the leg removed after several surgeries over the next two weeks. It was removed three times altogether, the last surgery being just under the knee.But it was soft tissue damage that caused it to be removed, as there wasnt enough left to keep the bone alive..

I was in hospital for five months..
The date of my accident?
May 30, 1983. Twenty years to the day, and almost the time, mine was about 10:30 AM

Bob H

 

 

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Seat interchangability (Tue Dec 23, 2003 3:14 am)

From: "Todd Johnson"
Happy Holidays All!,
I was wondering if it would be possible to install a single bullet seat & possibly the passenger pillion seat on an interceptor (mine is a 67' MK1A american version............Thanks , Todd

hi todd ; yes the bullet seat is doable . i have the same bike as you and got the seat on e-bay a while back for under 100 bucks .so search around .the installation requires some modifications but nothing major .the sea t i have on is from 2000 or 2001 model . good luck and happy holidays, ken smith in penfield ny

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High capacity oil pump from the Bullet. (Thu Dec 25, 2003 1:48 pm)

From: "Chris Overton"
Has anyone looked at adapting the hi capacity oil pump for the Bullet to a
Series II Interceptor? It delivers 50% more oil to the system on a Bullet.
Maybe this is the Inter pump, being made available for Bullets. Anyone know?

Merry Christmas!
Chris Overton
1B 1734

To expand on my mention of hi capacity Bullet pumps, Hitchcock's recommend a high capacity return pump to complement the feed pump.

100,000+ miles!!! I have no experience to report with my 0 miles project, but a
RE collector told me he has experienced wear problems on Inter exhaust rockers
from lack of oil.

Chris Overton
1970 SII, 1995 Bullet 500

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Final "lack of oil pressure" discussion for 2003! (Fri Dec 26, 2003 8:13 pm)

From: Dave H

Merry Christmas all!
I,ve been watching the discussion on oil pressure etc. with increasing surprise. Now of course it never gets to 30 C in South Wales here in the UK, but I raced an early '63 Interceptor in '68; rode all over the Continent of Europe, sprinted it (drag-raced to you North Americans!) and so on. In 1983 I bought a Series II which has been again very well used now clocking well over 100,000 miles (160,000K). I have a local reputation with this machine for not being afraid to open the throttle and keep it there.

The point of all this pre-amble is this: the big Enfields have their weaknesses, and I've probably seen most of them; but problems due to lack of oil pressure have never arisen! True, Enfields themselves increased the flow on the Series II by a factor of four; notice I said flow not pressure. I learned early in vehicle maintenance to almost disregard oil pressure gauges as they can give a very false impression of impending disaster. Piston pumps are in any case difficult to measure as they deliver pulses not a steady flow (as one correspondent found out; high readings at low revs, then at high revs but not inbetween: in other words, nonsense!).

Ole's comment that without cetrifugal force the engine would seize is true for all reciprocating engines; they are designed that way so that oil slung out from the big-ends cools the pistons from the inside. Royal, your remark concerning the pressure release screws is very sensible. The main release operates at 60 lb. and if it did not then the rockers would seize after a while. Anyone had that problem? No-one I know. It is intended to protect the oil seal from excess pressure and an increase here could be risky. There is a replacement part for the ball, part no. 49995, which allows a small amount of oil to pass in the event that the pressure drops as a result of the failure of the seal.

Two Series IIs were raced in the 24hr. Bol D'Or in 1970. Held in France on a banked circuit (Montlhery near Paris) both suffered transmission problems which prevented a good placing (after 12 hours one was holding 7th) but at no time did either engine suffer from seizure, bearing wear or any other lubrication related problem (I wrote the account in 1989 published in The Gun and could reproduce it if anyone wanted).

Racing involved running on the banking at 120mph (190K) for much of the time. Chris Overton mentions the high-capacity pump for the Bullet which might be a good idea on the 1 and 1A engines but just bear in mind that if you approach the return (scavenge) pumps' capacity too closely you will have a problem.

To conclude; I don't think that the oil-pump is a problem area on these engines. If it would stand racing then it will stand anything we can do today in normal use. I cruise at 75-80mph on the motorway with luggage and my wife without problems (except that **** oil seal coming loose!). I do use Penrite SAE 20-60 which seems very suitable.
Have a Happy New year!
Dave Hollyman

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David,

It's nice to have you join the discussion. You write you are being increasingly surprised by the inputs to the oil issue discussion. For the past 2 years we have seen many reports on how the tops are dry - or at least starved.

Personally I saw this phenomenon for the first time back in the seventies when my engine was new. True, that pressure guages are tricky, but when you remove an exhaust rocker cover when the engine is running good and hot ( - and your top pressure guage shows zero ) and don't get a mess all over the place - as you would on a well-fed engine - well, you kind of feel sorry for the engine - and you understand why those tops get so hot.

As a well brought -up ( dumb ?) young man, I put this observation aside as personal bad luck back then, and continued to ride the bike until it blew out the primary feed-seal. Not until Royal started this site and I learned that other owners had seen the same top-starvation, did I come to a clear understanding that the design is inadequate.

Given your input( as well as input from a few others), it appears that the design might only be marginally inadequte - so that some systems work and others don't - depending on a long chain of parameters such as tolerances and choice of oil.

Anyhow, my engine fell out to the wrong side no matter which oil I used - and as I want to give it lots of top-oil - especially when it's running hard - I for sure want a better pump !!!

PS : When I talk about the crank-centrifugal pump-effekt, I don't just mean the centrifugal forces whirling out oil to pistons and bores. I'm talking about the situation where the piston-pump has gone into "coma"-mode and is actually not participating at all in the oil supply. That's when the crank-centrifuge saves the day and sucks an emergency supply all the way through the supply line ( including the cavitating piston-pump).

I'd love to see your account on that 1970 Bol D'or event with the two Interceptors ! Will there be an explanation of the two cases of "transmission problems" - or can you remember what it was that broke down ?

A bit more on the oil subject : I ask you to please remember that the reason we are talking on this site is that we love these machines for all the other good features ! We also understand that the the guys at Enfield were working under very difficult conditions. They did, however, find out that something had gone wrong with the SII lube-system.

You present the evidence yourself : Why change the ball in the primary relief valve to a poppet with emergency drilling if there was not a problem ?? Certainly, if the problem could go away by changing the oil spec., this would have been an easier way for both engineer and manager.

To force through a design change - although small - at that time (69) must have demanded a lot of conviction ! My bike has also done long rides (Denmark - Spain -and back), but I never felt comfortable about it. The engine always seemed too hot ! When riding with other Britts, we would often - at stops - discuss why the "Fielder" seemed so much hotter than for instance a Commando that has much less total cooling surface than an SII.

Having dismantled the engine a number of times in order to stop the leaking from between the crankcase-halves - below the cylinders - ( distortion caused by excessive heat ! ) it was also obvious that the engines general wear rate was much higher than should be expected. Sorry for repeating myself, but : I put it all down to inadequate oil supply !!

Best REgards, Ole

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Hullo everyone,
I hope you all had a good time over Christmas and didn't get too drunk/overfed! Don was able to name the service bulletin that I remembered. I have one of the tapered valves which might be worth you fitting as it ensures oil getting to the top-end. If these are not available as spares it would be easy to make.

Ole, to take up your points: the Inters do get hot but they have a small (you might say inadequate) oil capacity, a lot less than a Commando. This is solved at least in part by fitting an oil cooler which noticeably reduced the running temperature of my Series II.

The only valve-gear wear I have ever suffered which occurred on both engines ('63 Mk. 1, '69 SII) concerns the guides which I understand to be because of a design fault, i.e. the strike angle is incorrect. (rocker to valve) causing the guide to wear oval. This is worth investigation, and might be easily cured by longer/shorter valves or even ball-in-socket tappet adjusting screws as available for the BSA/Triumph threes. To conclude! I think the Mk.1 and 1A might well benefit from a higher-delivery oil pump system, but the Series II is probably adequate given a cooler plus the tapered valve mod.

Don't let this stop you developing a new pump but I suspect this will not make the bike run cooler or last longer. In my experience the Commando has a much shorter crankshaft life expectancy than the Inter anyway, though this is more due to the Norton's poor crankshaft design rather than oil pump performance.

The leaking between the cases at the top is generally accepted to be because of
the fretting which takes place when the engine is running and is a direct result
of having separate barrels and heads. This can be seen by the witness marks at
the top of the crankcases. The only cure might be Allan Hitchcock's new alloy
barrels which are cast as one.

As regards the 1970 Bol D'Or, I still have a copy and will send it to Royal so he can put it on the site. The problems were all in the gearbox and concerned the sleeve shaft and some gears. You'll have to read it!

I wish you all Blwyddyn Newydd Dda! (Happy New Year!).

Dave and Ole,

The discussion on oil pressure and the release valve caused me to hunt up some of the old service bulletins sent to distributors and dealers. In particular Service Bulletin No. E.P. 4. dated March 1969 and outlining "A new type of release valve has now been introduced and all engines from number 1501 onwards will be fitted with a tapered valve having a small bleed hole taking the place of the 5/16" diameter ball ..."

It's function was to prevent the oil seal blowing out due to high pressures and even if this was to happen a portion of the reduced oil flow would still reach the heads through the bleed hole. It also instructs distributors to make the change on all remaining stock and to send copies of E.P. 4 to dealers with the new valves and ..."Each dealer should contact customers and pass over a valve with fitting instructions."...

Seems like you where on your own to make the upgrade yourself. They also recommend you "peen" over the oil seal housing to prevent the seal from being blown out. Might I also take from this that engine no. 1501 was built in March 1969? Certainly helps me put a date on the engine in my own 1970 S2. REgards and a Happy New Year.
Don in Niagara - 1B 1530

Two tangents for this discussion:
1. Don and others in the group,
-if there are service bulletins out there, is it possible to archive them in a website for all to access?
2. Serial numbers and shipping dates: -

I have a vague recollection of a story in 1970 that all Interceptors were built by some date in 1969. SII's leaving the factory in 1970 were from an accumulated backlog.

Does anyone know for sure? My 1B 1734 is recorded as leaving the factory on 6 March 1970. I know of another SII with a number ~60 less that is a 1969 and another one with a serial number ~250 higher that was shipped in February 1970.

It is like surplus production was wheeled into a warehouse and the last in was first out.

Chris Overton

Chris
For Number 1, http://www.ozemate.com/interceptor/pit.htm is a good start, knowledgebase et al
For Number 2 http://www.ozemate.com/interceptor/salesb.htm#alt21970 four big extras in the model... etc http://www.ozemate.com/interceptor/roymod.htm and model cronicle, also ref year model 71/72
REgards
Royal

Chris, I scanned E.P. 4. It came to about800kb. I cropped it to a more managable 100kb and put it in the Files section but it was not clear enough to be readable and I deleted it.

I don't know enough about computers to say why this is but I always have difficulty with print. The shots of my bike, also in Files, worked fine. I don't know why.

Anyway I could mail copies of what I have to Royal, maybe he could get them in. I also have E.P. 1, which is a summary of the changes in design that they made in creating the S2 model. and E.P. 2, the new primary cover with the timing hole and plug.

The E. P. service bulletins are by Reg Thomas. As well, I have a poor copy of the engineering drawings for the Interceptor oil cooler. This is by Royal Enfield Redditch, not E. P.- "Enfield Precision" but was "checked" by Reg Thomas.

REgards,
Don in Niagara
- 1B 1530 ...1970 spec. ...-sump guard, lifting
handle, oil cooler, and N*rton twin shoe front brake.

 

That's all for this year of 2003 Folks -- Happy New Year -- Royal.

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