Hitchcocks Forum

Hi all, I have a trials replica Bullet that I purchased recently. It came via a job-lot of bits from I believe the estate of a deceased. It appears to be a late '50's frame, with around a '53 engine. It had been rebuilt with many new parts, and frame powder coated etc. It looks very smart, but, clearly had never been run since it's build. The magneto was the only item that had not been refurbished, and was dead as a Dodo. I got that rewound and rebuilt, and was ready to put it on. Whilst it was off I had a look around the bike and found many things were quite loose, and came to the conclusion it may have been hastily bolted together before being properly finished. Upon receiving the mag back, I found the rear attachment strap was facing the wrong way, but an extended bolt was in place that butted up to the rear of the primary, necessitating removing the entire primary just to turn the strap around !
However, I'm glad I did, as I found the primary chain taught as a bowstring. The tensioner was missing the adjusting bolt, and so was as 'slack' as it could be. I removed the slipper tensioner, and found the chain was still only a little slack, in fact almost right without the tensioner. After struggling to get the two sprockets and chain off, (the clutch drum was rather rusty and everything was stuck fast), I laid the bits out and counted.
Now it gets weird.
The front sprocket has 25 teeth, and the chain has 90 pitches. This I believe is as it should be. The chainwheel has 56 teeth and I believe there are no other sizes. There are smaller sprockets for the front, but they use the 88 pitch chain. The guy at Hitchcock's was baffled too and suggested I measure the actual size of the sprocket. Though I think this would not help as size is relevant to the number of teeth and could only be bigger if it was for an entirely different (i.e. bigger) roller chain. The sprocket appears to entirely correct.
Any ideas ?
Cheers, Tony.

Just a thought, as the gearbox bolts on the back of the engine, are there any spacers between them?

Hi, no, gearbox appears to be bolted directly with no spacers/gaskets between the two.

Tony, there IS a bigger clutch chainwheel. As you may know the clutch and gearbox were made by Albion who also supplied other manufacturers. One of these were Greeves who used a larger clutch sprocket on some of their racers for eg, the Silverstone I believe. I have a Works Replica Trials (1959) which I am working on at the moment. I'll check the sprocket sizes but I'm pretty sure the front (crank) sprocket is a 17T and if you are planning on doing any off road this would be a better fitment. 25T is more of a roadster size.

REgards, Mark

Hi, thanks for the info, I would be interested in what size a standard chainwheel is. I probably will fit a smaller front sprocket, it seems easier than scratching my head forever trying to work out what the problem is !
Cheers, Tony.

Hi, just a thought, are the sprockets in alignment, if the bike was built from a job lot it could have a twin mainshaft, or the sprockets not pushed on enough. Vince

Hi, I have tried the sprockets with the primary cases removed to double check, still the same. The shaft centres are approximately 9 inches ( 230mm) between centres.
Cheers.

I've just checked (you are lucky, I was going to refit the primary cover today but replacing the camshaft bushes took too long!) and the standard clutch chainwheel is 56T. The racing one I mentioned is 54T. What Vince means is that if you have a Twin gearbox mainshaft (which is longer than a Bullet,) the clutch will be too far out into the chaincase and therefore out of line. I can't think off hand what your problem might be but I have known new chains to be very tight, they quickly wear in though! One other thing, the pre-55 Bullets had a smaller crankshaft journal diameter than the later ones and therefore a different sprocket with a smaller spline.

REgards, Mark

I recall a story told to me by an elderly gentleman over a cup of tea several years ago who owned (amongst many other vintage bikes) a 'genuine' works trials Enfield which he was gifted when he left RE before moving onto BSA.
The Enfield in the latter part of its life was borrowed by a supposed friend. When he eventually got it back the bike no longer running because many of the unique works factory internals were missing which were explained away by the 'friend' as being stolen during a garage break-in. The missing parts were not interchangeable with bits available at the time or as he sadly discovered from any subsequence RE built since. I know that this particular bike will certainly cause a lot of head scratching when it passes onto it next owner.

Thanks guys. So I have the standard chainwheel, and everything is in line. I guess I'll just order a smaller front sprocket and not worry about it.
Works bike eh ?
That would be a great thought, but I doubt it ! I shall post a pic sometime. I have joined the RE club, so will get the bike registered once I get her running. Thanks for all the input.
Cheers.