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Discussion Starter · #1 ·
Long story short, high mileage bike that I have ridden for 4 years and 8k miles. Suddenly while on a long trip it starts running wrong. Get home and the points gap is very small, contacts are nearly destroyed, and spark is weak.

Got ahold of two new sets of points. Cleaned and lubed advance mechanism. Went to set timing, and spark occurs too far advanced for adjustment. I have tried all ranges of point gap. The adjustment range runs out long before the spark would line up with the LT mark. Photo shows are where spark occurs. At this point I'm super stumped. It's been discussed here on sohc4:

SOHC4 post

advancer pin

rotor
 

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Discussion Starter · #2 ·
Right now my main hypothesis is that the cam chain may have skipped a tooth forward (on engine deceleration) due to high mileage and loose cam chain. Leading to an advanced camshaft. Other than that I can't think of anything at this point which hasn't been gone over on SOHC4 (various questions about advancer unit, points, points gap, etc).
 

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Timing is set at LF and for the right at F, not LT or T

If you got those points from Common Motors they had issues that required modification to the points. Points from lots of suppliers are crap these days.

If the cam pin is in the position you show in the picture and the rotor is on LT then IMHO you didn't skip a tooth on the camshaft.
 

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Discussion Starter · #4 ·
Timing is set at LF and for the right at F, not LT or T

If you got those points from Common Motors they had issues that required modification to the points. Points from lots of suppliers are crap these days.

If the cam pin is in the position you show in the picture and the rotor is on LT then IMHO you didn't skip a tooth on the camshaft.
Sorry LT was a typo. You think the cam pin is within the margin of error to be on spec? If so do you have any suggestions for why the crankshaft seems to be advanced? (I know it isn't but you know what I mean, since it is like 5* forward of where I would like it to be).
 

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Discussion Starter · #7 ·
Yes, it is correct as the spark is occurring at the LF mark after compression stroke on left side.
 

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Discussion Starter · #9 ·
Removed engine and top cover and the cam sprocket is as advanced as the timing and advancer pin showed.
 
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