Breaker plate adjustment constraints on GS750E

Russell

In fitting new points to my 79 GS750E, using an inductive timing light for adjustment ,I've found that I cannot rotate breaker plate far enough to be able to perfectly line up timing marks for 1-4, then 2-3. I can see how I could gain enough movement by extending slots with a file but am guessing the reason for this is actually wear in the cam that the heel of the points runs on. Anyone had experience of this and any sage advice? Bike is running okay as is with current adjustment which is 1-4 spot on but no adjustment left while on the 2-3 idle adjustment I can only get the mark halfway between the F and the T before run out of movement.

dorT500 · Posted: Sat May 01, 2010 9:50 pm Post subject:

Have you sorted it out yet? Here is hoping that this will at least get you another shot for an answer. Wink

Good luck

Russell · Posted: Sat May 01, 2010 11:12 pm Post subject:

Thanks. No...not sorted yet . My brother who is a handy engineer thought that the cam-chain could be a tooth out but I doubt that as it would not run as well as it does if that was the case. Rode it today and it went as well as it ever has in the 4 years we've owned it. I've never had a strobe on it before so don't know how closely the marks aligned previously.
What is apparent as I look through at the marks with the strobe is that it takes only about 16-1700 revs to flick the mechanical advance to full advance...in fact it goes well beyond the T mark so I'm fairly sure that the advance unit and associated points cam is well worn. The manual says this should be tested at around 2500 however it doesn't indicate if advancing earlier is an issue.

pd · Posted: Sun May 02, 2010 11:46 am Post subject:

You think maybe 30 year old springs get weak ?

I went to weaker springs to get the earlier advance and am pleased with the results . I should add that the springs are not the only thing I have changed in order improve over all performance .

Granted different manufacturers , but ...