Hi, if you took it apart yourself you’ve probably discovered the two possible problems on putting it all back together again.
1. The clutch nut is left hand thread and the clutch basket extremely brittle. Hence lots of broken outer baskets ! On doing this up I’d really recommend making a proper clutch holding tool, using one of your plain and one of your bonded plates. If you just drill and bolt them together to do this there’s no reason why you can’t then re-use them for their intended purpose if you make sure there are no burrs, etc. If you try to lock the clutch in any other way there really is a very strong chance you’ll shatter the outer basket.
2. Cam timing. If you have a “Sprint†you have the potential for infinitely variable valve timing. Great if you want it, not so great if you just want the standard timing ! On taking the engine apart, if you marked which of the internal ‘notches’ on the pinion which goes on the end of the crank the pin on the crank engages with, you’re laughing. Similarly if this is already marked on the inside of the pinion (from my experience very few are) you are OK (as the gear on this pinion is marked where it engages with the cam gear, so this shouldn’t be a problem). If this pinion on the crank is not marked, or you didn’t mark it yourself you are going to have to time this up by hand, using a gauge, etc, to judge valve opening times. I do have a diagram to indicate which ‘notch’ is correct (I’ve helped two or three people previously on this) but as I’m out of the country at present I couldn’t get a copy of this to you until late June at the earliest unfortunately.
Other than that there is not much I can think of off the top of my head though make sure you’ve kept all the original engine nuts, as things like the barrel base studs are 5 or 7mm fine thread (as may be head nuts ? ‘can’t remember) which are almost impossible to get hold of. Ignition timing can also be a problem, but I can’t really help on this one as I have used the complete electronic kits obtainable from
http://www.powerdynamo.biz/eng/systems/ ... 75main.htm which I now note are now not far off £400 ! ‘Struth they’ve gone up, but for this you do get a complete electrical system for the whole bike, 12volt, which replaces the dodgy regulator, stator, etc. It also takes the ignition timing directly off the end of the crank on the right, rather than off the end of the cam (on the Sprint) on the left of the engine, which I reckon has to be a more direct and accurate method.
Anyway, good luck with the rebuild and as a request could you send me any of your sources of spares, as I’m always looking ?
Cheers
Pete
PS. Are you a member of the club ? If not, join ! I regularly put items in the magazine, which will help you with the rebuild.
PPS. I am desperate for some valve collets (i.e. the split ones which are at the top of the valve and hold the spring). ‘Don’t suppose you have one or two spare ?