weird timing issue

[andoor]

So I got the timing of my bike (cb360) dead nuts at idle but when I rev to full advance one cylinder is right on. While the other is jumping back and forth from the full advance marks to about 30 degrees of more advance. The motor starts popping and sounds horrible at this point.

These are still the points that came on the bike when I got it so I am going to order a new set. I just wanted to get a better idea of why this would happen. I assume that if it was a problem with the mechanical advance both cylinders would be affected.

Could it be that the spring on the point for that one cylinder is no good, and at high rpms it can't keep up?

Any insight would be great.

Thanks

Andie

 

[crazypj]

Ignition was left on at sometime, the points return spring overheated and got weak.
What your seeing is points 'bounce'

 

[Tim]

So am I right in guessing that you can check the timing of each cylinder by using the strobe light on each plug wire? Funny, I never thought to check each one on its own On my XS650 with Boyer (computer controlled advance curve and magnetic 'points') it wouldn't (shouldn't) make a difference but on my BMW with mechanical advance and points, they could be and likely are different.

I'm going to a full Boyer kit on my BMW but will in the meantime check the two sides to see if they're both in good shape.

 

[andoor]

Thanks for the info PJ

Tim
Yes I did use a timing light to check each cylinder. I set the timing static with a test light first and it was pretty much right on when I put the strobe on it.

I will have to look into these Boyer kits.

 

[andoor]

New points fixed the problem ;D