Fuel starvation or ignition? Surging but not dying

[chuck hahn]

Since you mention an "ignitor" I am assuming it has CV carbs. See the sticky at the top of the carb section on CV TUNING PROCEDURES. My guess is some float level tweeking will cure the ills. Its the first thing I would check anyway. Too low and they drag at the lower RPMs like near 3,000 or so. Too High and they tend to hit so rich the cylinders cant burn it all and it gets a jerky feeling to it. Start it and have a buddy run it up around 5 and stand behind it ..bet it smells gassy as heck.

[Buffalo Bill]

I took a ride and because the issue is predictable, I can manage it. If I do not do any hard accelerations, it will run normally.
I'll buy a used CDI from ebay, seems I've been working around issue.
It feels like the ignition is not advancing the spark, or cutting out 2 cylinders.
One last thing, I'll clean the CDI connectors.

[chuck hahn]

Have you pulled the timing plate and cleaned the governor and the crank end to be sure there isnt any sticking going on down there?????

[Buffalo Bill]

Yes Chuck, tested the sensor too. All good.
It has electronic ignition, not points.
I bought a used CDI box today, last thing to try.
It acts just like an old car I had, new points and condenser fixed it.

[ukjules]

Im late to this thread but will add things that happened to me with similar issues:
As I absolutely know you know what you are talking about so i reckon this is a simple thing you will have
overlooked.


- Is it fuel line kinking ? This for me produced the same issues as you are experiencing !
- Is it petrol vacuum line kinking to carbs ?
- The connection from the pickups to the coils (usually a plastic connector box) might be loose.
On one of my bikes again it produced exactly the same issue you are experiencing.
simply wiggling this when the hesitation started made it go away.
A new box and connectors solved the issue.

[limeex2]

Seems the most unlikely thing, but I will check that too.

Tank bags can block fuel cap vents. Has happened to me before.

[Buffalo Bill]

OK, finally found the issue: bad 2-3 coil. Seems good until hot, then bum.
Replaced it with a salvaged GS coil I bought a few years ago for a GS550. Same specs, different mounting configuration.
Just did an hour test ride with a few hard accelerations, no return of the problem.
All the other work I did and parts I replaced is for the good too, because they tested bad anyway.
Case closed.