52mm bbk weird jetting issues By millsc (Read 787 times)

[millsc]

i put in a 52mm bbk had a 50mm bbk in it before i ran a 38 idle jet that came with the carb and a 92 main jet after the kit i it wouldnt idle steady i turned the a/f screw all the way in and it kept running so i knew the jet was too big so i switched to a 35 idle and that fixed the idle but the 38 worked fine with the 50mm kit i have a 98 main jet in it now but its way rich so gonna put the 92 in tomorrow why would i need smaller jets with a bigger size bbk im stumped i did seal everything up real good this time and replaced all the gaskets

[Alleyoop]

Just remember if you measure the 50mm and the 52mm there is not that much difference between the two. A mm is hair thin so it was most likely the 50 had much better compression at the time and would handle the little rich side. Also Valve gaps make a big difference as well little on the loose side will suck in less gas and air so you can be little overjetted and will not notice it right away. But I would think a #38 right off the bat would be just to much for a 50, mind you a 150 24mm carb comes with a #35 pilot and with me adding 30more ccs on my Trike it only took a #38 pilot from the original #35.
Alleyoop

[millsc]

its strange it wouldn't handle the 38 idle idled strange where the 50mm ran fine with it the 52 seems to have more compression its harder to kickstart if that even matters the 98 is way big so im thinking the 92 will work as well maybe i had a leak somewhere with the 50mm it did backfire from time to time doesnt backfire now i used all new gaskets and sealed everything up tight

[Alleyoop]

Well you know backfiring is LEAN, so you most likly had a leak someplace.
Alleyoop

[millsc]

so i guess 92 main jet will be ok with the 52mm i got a new plug and gonna try it tomorrow

[millsc]

air filter was dirty it runs great now still kept the 35 idle jet

[Alleyoop]

Good to hear the #35 is good and a dirty air fliter.
Alleyoop