Royal Enfield Interceptor Owners

Just to clarify privacy, please check our privacy statement -->>

Discussions on Bearings (Sunday, 1 February 2004 9:02 AM)

From: Chris Overton

I have finally got my Series II engine apart, finding many surprises - good and bad. There is debris in the crankcase from a piston melted long ago and silicone-like gasket sealer everywhere. I think that necessitates removing the plugs from the crankshaft and ensuring the oil passages are clean. To do that I must remove the crank from the drive side of the crankcase and the directions in the shop manual confuse me. It is possible to heat the case in a tub of boiling water and tap the bearing out (using a piece of PVC pipe for a drift). Does the bearing truly tap out then? Or pound out?

The part I am having trouble understanding is re-assembly. With the bearing on the crankshaft, how do I get the bearing back in the case? Do I have to pull the bearing from the crank, install the bearing in the case, then pull the crank into the bearing?

Next issue will be the con rods. One small end bearing is definitely ruined. Is it possible to bore out the bearing diameter and install a bushing? Or put in a bigger gudgeon/wrist pin? What is the experience out there?

Many thanks,
Chris Overton and 1B 1734
Rossland BC Canada

Chris,
Can't wait to hear the answers for this. I have the heads, jugs & pistons off my Series 2, I'll be starting the tear down of the main case probably monday nite after work. (as tomorrow is fully booked with the Superbowl).

So far, i noticed that the connecting rods have a bit of side-to-side play on the crank, that makes me a bit scared. How much is too much? do i need to replace them if there is any slop at all?

Cliff

Chris:

Unless your Series II is different from my Series 1A, the crankshaft oil plugs are aluminum and are staked in place. No amount of heating, leverage or pre-soaking was enough to enable me to shift them. I ended up drilling out the center of the plugs just enough to get a junior hacksaw blade into the hole, and then slicing a series of radial cuts all around the plug, just to the depth that I started to catch the tops of the steel threads in the crankshaft.

Eventually, I was able to take a punch and collapse the plugs out of the threads by fairly gentle tapping. This process left a lot of swarf behind, the clean-up of which was probably the most tedious part of the process. Of course if you have to use this approach, removal of one plug isn't really an option.

While I may have created problems I've not yet discovered - it's all still in pieces - I did use hot water to heat the drive side case before taking a hide mallet and driving the crankshaft from the bearing. I allowed about 10 minutes for heat to build up and removed the crank with only moderate effort.

FWIW. Good luck.

Rod
1A512

Rod,

I managed to get the alum. plug out with some difficulty and without ruining it. Good thing - the crankshaft has chunks and sludge inside. The crank is not budging so I won't force the issue, just work around it.

Today's project is to get the forks apart to see what is left of them. /Chris and 1B 1734

Chris,
Just curious : How do the mating surfaces of your housings look - at the upper part, between the cylinders ? Good work ! Ole

Sorry about the delay in responding to this: I'm even more busy than usual, but I have some things to add.

Be very careful when dealing with the main bearings. They are a very tight fit on the crank stubs, and I have seen at least one that stayed on the shaft, and the outer race knocked out the back of the bearing seat in the crankcase ... over-zealous pounding I guess when someone was trying to get it out.

The right way is to heat the case and bearing at one time, but keep the crank cool with a wet rag. Lacking the factory tool, use a press to push out the crank. The bearings are often good, but if it has sat around, may be scrap because of rust in the bearing tracks. They are inexpensive, so no point taking a chance. Boiling water is no good, because you'll heat up the crank as well. You need as much differential expansion as you can get. Please do not pound it out. In addition to damaging the cases, you may also wreck the detail that engages the alternator drive (seen lots of those too).

BTW, the bearing comes out in the opposite direction to the crank, and must be re-installed in the cases prior to drawing the crank back in. Be careful to put the beveled washer back onto the crank stub first!

The rods are a must to remove and have a look at. I always take them off, and have them re-sized to ensure a good fit with new bearing shells. The nominal clearances are less than 0.001", so things have to be perfect.

The small end of the rods can not be bushed in my opinion: not enough material. A bush from a BSA DBD34 Gold Star has a suitable bore and about a thin a wall as you can imagine (about 0.032"), but it needs a steel rod to hold it in shape. I think you'll be looking for a pair of rods. Be very careful that the Helicoils in the rods are perfectly clean. I have seen them seize onto the rod bolt, and jam in the outer thread as the bolt is unscrewed outward.

Be careful also not to substitute the bolt: they are a very special hardened grade with the threads being rolled after heat treating. The shanks are ground to size to suit the rod cap they're fitted to, so as to act as a locating dowel.

I noticed in your latest message that your cases do not mate well. Not good: your 1mm gap is quite severe, and you should really get to the bottom of what happened. Loctite 515 or 518 is good stuff, but the surfaces really need to mate well first. There's lots of stress, and the sealant will simply fret.

Also, it is wise to scrap the factory screws holding the top of the cases together, and fit a couple of Allen screws. First, fit Helicoils to convert them to standard American threads to make the job easier (I wrote this up a while back). I use a button head screw, and machine the head a bit to fit the counterbore in the cases. Yes, the thin washers are necessary .... and are also to be fitted under the heads of all the screws holding the timing cover on. Many get lost over the years of careless disassembly.

The timing side bearing requires care as well, and it is easy to have the outer race become distorted if not fitted carefully, but I'm going to have to leave it for another time.

... gREgg

Cliff,

Side to side movement is not a measure of wear. Rods must always slide side to side in order to compensate for alignment tolerances.

The only reliable way to check the wear is to dismantle the big ends and measure the crank journals with micrometers, and the rod bores with a bore gauge. Trying to do anything with an assemble engine is futile because of the oil in the bearing surfaces ... they have to be truly horrible before you can feel the slop otherwise taken up by the oil.

.. gREgg

---

Discussions on Crankcase Fit (Tuesday, 3 February 2004 11:30 AM)

The surfaces of the crankcase halves between the cylinders look fine I think, but then I have never seen others. (The screws that hold the halves together between the cylinders were both loose - yet another reason I am glad the previous owner could not start the bike after his rebuild.

One screw has a washer, the other does not - and the extra washer I found inside the crankcase does not fit there.) The surfaces of the castings touch in only a few places: strips beside the cam tunnels and a strip beside the inverted U cutout directly between the cylinders.

When the crankcase halves were machined flat, that part of the castings was not high enough to be cut smooth. I must be sure to put some gasket goo in the void on re-assembly. I don't mind the extra ventilation, but water entry would be a nuisance. Two questions arise:

1. Should I lap the cases to try get more contact? Full contact would move the halves a millimeter closer together.

2. What sealant should I use between the crankcase halves? Someone recommended Loctite 515 as being ideal for such applications but I have no experience with it. I don't want to use whatever the silicone-like stuff is that was used previously. If any squeezed out it would plug oil ways.

Thanks in advance for any advice from anyone with more experience,
Chris and 1B 1734

--------

gREgg,
Thanks for all the tips from your experience. I am sure others are taking notes as well.

No mystery about the case halves. They simply were not machined enough, or there was not enough material to machine. How do I tell which? Is lapping a cure?

There is no sign of the case halves working against each other. 9000 miles on the odometer so we know that is the minimum use. And I suspect they were hard miles, judging by the steel clutch plates that engage the hub. The tangs are hammered nearly right off.
/Chris and 1B 1734

Holy Smokes! I've never heard of this happening before. The Series II I had from new had an engine number very close to yours ( it was 1B1732), but I remember the machining was of good quality. Sounds like the person who did the machining of yours had a moment of inattention, along with everyone else who worked on it.

Why not email me a photo the cases to be sure. Lapping would be very slow work when the mismatch is as much as 1mm, and would be very tricky around the crank area, where the spigot has to remain a close fit. If the 'bad' area is only on the flat side, you may be able to rub it down on a surface plate. Be careful though, because the bearing bores for the crank must remain absolutely in line. Sounds like a job for a skilled machinist, but I'd still like to see a photo...

I know what you mean about those signs of abuse on the clutch plates. I've seen the drive tangs burred and damaged, and the friction surfaces scored and burnt over the years. Many times the primary drive has been run dry, and the clutch bearing is burnt blue. I ride in as spirited a manner as any one I know, and I've never been able to inflict anything but normal wear on my bikes. The people who did the kind of damage you describe must have been of 'special' parentage.

.. gREgg

-------

Chris

When asking you about your surfaces, I kind of expected the answer you have given.( I don't understand Greggs holy smoke !?) It's not that I feel happy to be confirmed, but this is - in my book - the most obvious and serious problem of the SII - and I don't think anyone can say they don't have it - unless they have done some radical modifications.

I don't believe that the phenomenon you have observed stems from the Enfield Precision Works machining department. I'ts an (until you've seen it a couple of times) unbelievable wear phenomenon that is caused by a combination of unfortunate thermal conditions and the alternating load from the separate cylinders.

You can have your faces remachined - and live the inconveniancies that the 1 mm smaller centre-distance gives you. That would, however, be like pissing in the pants to get some warmth - because that bad stuff will happen all over again if you don't do something else!

Ole

Ole,

"Holy Smoke" is a Canadian expression of surprise and disbelief. In this regard, I meant also to convey my empathy for the situation.

From Chris's description I didn't think he was describing fretting wear ... it sounded like incomplete machining to me. That is why I asked for a photo, to better assess it.

...gREgg

Gregg,

I'm fully familiar with the expression, thanks - I was just amazed that an SII connoisseur could be unprepared for Chris' description - although, off course, he did excagerate a little with the 1 mm.

I would say that a typical necessary machining depth is in the region 0,25 - 0,35 mm so that the centre-distance is reduced by 0,5 - 0,7 every time you do that process ( I'm on my 3.rd - and last !

Ole

Ole, gREgg, et al,
The 1mm distance I estimated from my keyboard, which is far from my shop, is a bit high. I don't know that a photo would reveal much more than my description. The surface of the part that appears un-machined is 'pebbly', with no signs of smearing. The machining marks are still in the strips that were milled flat, and the demarcation between milled and unmilled is sharp in some places, so I don't think there has been movement.

Today I picked up a piece of thick glass for a flat surface to gauge the cases. Next, the glass may be used to lap the cases if they need it. I cannot find abrasive paper larger than 9 inches x 11 inches to do the lapping. My only option so far is to glue 4 sheets to the glass - sounds hokey to me. Does anyone know a better way?

I don't think it is the end of the world to have the small gap. There is lots of machined surface to bear the forces of the halves being forced together. The gap can be filled with sealant on assembly. There appeared to be no sealant in the joint between the halves. Should I use something? Loctite 515? Or is it supposed to be oil tight without sealant?

Chris

Hi all,
There's no doubt that fretting at the top of the crankcases does take place. In this respect, Allan Hitchcock's one-piece alloy barrels would seem a permanent solution. The surface of my crankcases (high-mileage) does indeed have a "pebbly" appearance and when purchased (in 1983) were not flat.

I went to a specialist machine shop which took about 40thou off (that's about 1mm) to get it flat. In fairness, my SII was made up from spare parts in 1976 by the dealer and some parts were highly suspect in condition and may have been factory rejects!

There is no problem with taking 1mm off. The cams do not bottom in their bearings, the r/h conrod has sufficent side movement and because the main bearing on the timing side "floats" (to allow for differential expansion) it may only be necessary to tap it 1mm further onto the crankshaft during assembly (the manual says to tap the bearing on to the shaft to within one-sixteenth inch of the web).

Heating the crankcases (gently!) with a blowlamp will allow easy removal of the crankshaft and then the drive-side main bearing. Because aluminium expands further than steel, you need not worry about the bearing becoming warm.

When refitting again heat the cases (you can put the bearing in the freezer for a while) and then tap it home. Personally I recommend entering the shaft then by use of spacers drawing the shaft through the bearing with the sprocket nut until fully home. Just to mention; the spacer must be the right way round (taper against the crank web)!

Loctite 515 seems good; silicon can be used on the crankcase halves but only if done sparingly and taking care none forms inside the cases where it can form globules that block oilways.

Cheers, Dave

---

Fork removal Discussion (Wed, 4 February 2004)

Thanks again for the prompt knowledge to all,I have a 67' MK1A , & was wondering how to remove the forks from the head bracket , i have the manual but it isnt very clear ,it appears that the fork screws into the head bracket& needs a large allen head wrench/spanner to unscrew the fork , is it that simple , or will it do something unexpectedly scary??

I think you will find 3 pinch bolts under the fork crown that must be loosened first. Two pinch bolts are tangent to the stanchion tube, and there is one more on the main steering stem.

Once the pinch bolts are loose, you unscrew the stanchion tube from the crown using a 1/2" hex Allen wrench. Very simple once you get your head under there to have a look.

.. gREgg
------------

Re: fork removal. The 1/2" wrench can be formed by..... an Enfield footrest bar! It fits perfectly.

Does anyone have drawings or dimensions for the frame? I have a pal who was unlucky enough to ram a car recently. He has been to a frame repairer but needs some figures. It's a Series II; what is the fork angle (rake)?

Cheers, Dave
PS Gregg you were right about the Triumph unit tacho drive, I must be confusing it with something else. Old age again, I guess.

Cheers, Dave

---

Help on Wiring harness (Thu 5 February 2004)

Hi guys
I will be making up a new you beaut harness in the next couple of
months. Does anyone know what amps wires to use?

Kickan,

There are two things to keep in mind with regard to your choice of wire:

1) current handling capacity, to pass electricity with as little loss as possible. For this you'll need wire of 16 gauge ... 14 gauge would be good, but may prove awkward to work with.
2) flexibility, so as to withstand vibration. For this you will need wire with a fairly thick thermoplastic insulation, and a core made up of as many fine strands as you can find.

I don't know what is commonly available in Oz, but in Canada there are numerous choices. The finely-stranded wire core is rather important to prevent fracture due to work hardening in use. German wire manufacturers seem to excel in this regard ... so your best option may be to visit a breakers yard, and get a few lengths of a wiring harness from a VW or similar.

...gREgg

---

Interceptor with indicators? (Wed, February 11, 2004)

FullName: Seb Clarke
Message: Just browsing really - haven't had a bike running for a while but if and when I get chance it'll be an Interceptor of some kind - and I just noticed a picture of a 71 Interceptor on this site which had indicators...

Did they come from the factory like this and roughly how many from that year are still out there?

Cheers,

Seb Clarke.

Hi Seb

Sounds like a well worth goal, hope you find a good one. One guy here in Rockhampton Australia (about 400 miles north of Brisbane) bought one from the US and had shipped here. It's in very good gondition.

The Interceptor you refer to, in our little art gallery, is a 1970 model. It has a pair of side panniers. These had inbuilt indicators at the back. I felt compelled to match with a pair facing forward as well.

There are also "daylight" lights facing forward 21 Watt lights which were a standard commonly adopted in Sweden during the early eighties.

So, none of these lights are standard but were fitted
separately.
Regards
Royal

 

---