717 Performance issue

[Michael Cain]

I'm hoping that someone can shed some light on my issues. So here's the problem, I recently purchased a 96 speedster with twin 717's. One of the motors is very slow to rev and feels very week after 30 minutes on the water. Today is started backfiring through the carb and will not run. I ran a compression test on both motors and all cylinders are good. I have swapped carbs but no luck, same issue. I assume that the issue is with timing or the rotary valve? Has anyone dealt with this issue?


Thanks,
Michael

 

[Dr Honda]

If the power was dropping after time... that is normally an issue with over heating.

What was the compression?

Back firing is normally from an air leak. You may have a manifold, carb... or crank seal leak.