Timing Pinion

[Bulletbaz]

I am wondering how the standard, indian manufactured, timing pinion stands up to the rigours of competition camshafts? I ask this because I have read on another forum of one that broke up, causing considerable damage (I beleve it was CJHeff's 612). Has anyone else experienced this, or was it a freak occurrence? Can anyone vouch for the durability (or otherwise) of the stock pinion?

[The Garbone]

Like most things I think it would be luck of the draw in that a failure would just be under the heading, damn the luck.  There really is not that much involved in the timing pinion as it is just a machined gear.  I imagine it failing would be the result of bad manufacturing or poor quality metal to the severe.  I would not be surprised by it but would not worry about it all that much.  You can always buy one of the aftermarket 3 way timing pinions if your concerned.  I put one on my rebuild,  looks to be of good quality.

[ace.cafe]

Haven't seen any problems.

CJayheff was running some serious over-compression, and had a bunch of piston failures, and broken cylinder spigots, and just wouldn't face the fact that the pump gas wouldn't support so much compression.

It wouldn't surprise me if he had some monumental kick-backs that might have wrecked a variety of things, including possibly the pinion.

I wouldn't use his experiences as examples of normal Bullet behavior.

[Ice]

FWIW I have never heard of one failing.

[CJay]

ace.cafe
Grand Gearhead


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Re: Timing Pinion

« Reply #2 on: April 29, 2012, 12:27:00 PM »

Quote


Haven't seen any problems.

CJayheff was running some serious over-compression, and had a bunch of piston failures, and broken cylinder spigots, and just wouldn't face the fact that the pump gas wouldn't support so much compression.

It wouldn't surprise me if he had some monumental kick-backs that might have wrecked a variety of things, including possibly the pinion.

I wouldn't use his experiences as examples of normal Bullet behavior.

==========================================

CJay's answer: (a friend told me of this post so I thought I would reply. I don't do the forums anymore).

TIMMING PINION

The pinion failed because it was not made to specs (all to common with Indian REs). Thanks to Tim-from-NZ for figgering this out for me. The pinion fits on a keyed tappered shaft. It is an engineering no-no (you can check any edition of the Mechinery Handbook) to bottom the gear on the key because it will eventually break at that point. This was the case with my pinion. I always wondered why I could never get the jaws of the pionion gear puller behind the gear. I always had to use a thin chisle between the gear and the case to get it off. I just did not have the experience to question why at the time. I always though it was just another piece-of-junk RE tool. Tim is the NZ importer for RE and has seen this (and so much more) more than once on stock REs. I recommend him for anything English with two wheels made before 1990.

CYLINDER SPIGOTS

RE uses a spigot system like the old BSA goldstars did. Now REs never were BSAs but even the BSAs had problems with this design. So the first problem is that you are trying to seal two geometric planes (oil and compression) at the same time. Can't happen. BSA came close enough with a layered cylinder head gasket you could (adjust) by peeling off layers of the gasket. So the minor problem is oil leaks in the head. Messy but no big deal. Moving on now to the big problem. The compression spigot on an RE is normally two hundred thousand wall thickness. Now us hot rodders come along and bore the cylinder out for 535 and 615CC engines. So now that spigot is only one hundered thousands wall thickness. Couple that with horse power increases in the twos-table and you have a problem. The least of which is noise. You have basically a F'in bell (cylinder head) sitting on top of your cylinder. In my case you also have zero room for any stress. I fixed this problem by eliminating the spigot and remachining the head and cylinder to fit like a Honda or Ducati would.

HOLES IN PISTON

All caused by very poor quality points advance mechanisms. The slots the advance wieghts rode in peened out at the ends causing burrs that would at times hang the wieghts up in full advance. I caught this one day when doing a routine check. It hung up once when I turned the points cam to full advance but the second time I did it worked OK. Repeating the check would produce a hangup once in about every five or six checks. The fix was to go to a boyer electronic ignition.

I pulled the mechanical mechanism out and photographed the problem. I am sure I posted in somewhere on the old Bullet board but can't find it now. So if anyone would like to see the pictures (which don't lie) let me know and I will email them to you. You can reach me at cjayheff@comcast.net as I will not be monitoring this or anyother such forums.

CJay

CJay