- Joined
- Apr 22, 2020
- Messages
- 2,988
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I'm curious as to what the current trend in spot on idle AFR is for the motorcycling community?interesting. i'd never heard of the firebox device. this old T120 has a 750 kit, some minor port work with OS intake valves, a mild cam with some extra lift and duration, the twin plug head, and 34mm VM mikunis. i've tuned the carbs with an AF meter and they're spot-on at idle and slide cutaway. i settled on 30 BTDC advance at an airstrip using timed runs, testing both ways at 2-degree increments to settle on 30. the problem is just at off-idle which otherwise could have been the slide cutaway.
it's possible the 34mm carbs are a bit big, although the head was ported for them. but i know the idle advance is certainly low, so i'm interested in correcting one thing at a time. i might go back to 32s if that doesn't fix it.
I think a lot of people set their toys up too lean. Todays pump gas has a different stoichiometric value than it did 45 years go when a lot of documentation about tuning was written. Just blabbing. I know nothing.