Motoscrubs.com

Full advance is determined by two tabs on the AAU base plate that limit the bobweight travel which in turn advances the point cam. If you have too much advance, bend the bobweight stops in a little until you get the advance you want.

I would be a bit concerned with the amount of advance you have there, and would start with less, say about 40. If the slots in the baseplate are not enough you can re-position the gears a tooth or extend the slots . The big ends are not over designed and if used for running around at low revs they can knock out. A bit less adv will give it an easier life.

Points gap has no effect on advance range.

double diamond wrote:Full advance is determined by two tabs on the AAU base plate that limit the bobweight travel which in turn advances the point cam. If you have too much advance, bend the bobweight stops in a little until you get the advance you want.

That's a really good tip DD, I'll have a look at that. Many thanks!

The points gap does not affect the range of the advance mechanism,however it does considerably affect the timing position. Moving the points plate on the slots is much cruder than you would expect (anything you do is doubled by the gearing) . I set my points very carefully and note exactly what the gap is ( not that easy as the points cam is a bit odd anyway) . When I want to make a fine adjustment to the timing (usually because it tries to kick back a bit more than is comfortable or won't idle regularly) then I just reduce the gap by a thou or two which retards the timing by a few degrees. This is easy to do on the roadside and can be reliably reversed just as easily. Just need to carry a screwdriver and feeler gauges. On my bike the points just act as a trigger for an old fashioned transistor booster so the actual gap is not critical in any way as it does not control the dwell .

Bevel bob wrote:The points gap does not affect the range of the advance mechanism,however it does considerably affect the timing position. Moving the points plate on the slots is much cruder than you would expect (anything you do is doubled by the gearing) . I set my points very carefully and note exactly what the gap is ( not that easy as the points cam is a bit odd anyway) . When I want to make a fine adjustment to the timing (usually because it tries to kick back a bit more than is comfortable or won't idle regularly) then I just reduce the gap by a thou or two which retards the timing by a few degrees. This is easy to do on the roadside and can be reliably reversed just as easily. Just need to carry a screwdriver and feeler gauges. On my bike the points just act as a trigger for an old fashioned transistor booster so the actual gap is not critical in any way as it does not control the dwell .

Bob, I'm glad you confirmed my understanding and results of the effect of the points gap on the timing, I was starting to feel even more stupid than normal!

Yeah, I get that the actual range of the AAU can't be effected by the gap, I was just trying to bring the full advanced readung down as close to the upper limit as possible for the moment as you rightly say.

I'll have a go at adjusting the tabs on the AAU as suggested by Double Diamond, once I've got the engine back in the bike now.

I'm just in the middle of fitting a new clutch kit and then I can button it up and make the frame look more like a motorcycle for the first time in years!

IF the clutch is still a problem , Nigel lacey does a pack of thicker plates for the 250, may be the same, for your bike that stay flat.

Bob, that's worth knowing. I actually got the clutch kit from Nigel, but the standard one for the 175s with his own plain plates.

Hopefully all will be well but it's always good to have options!