cb500 twin carb issues, runs rich with open pipes and intake and factory jets?

jakeoff51

jakeoff51

New Member
hi guys got a question for you. from my understanding when you open up the exhaust and intakes on these bikes it usually leans them out? in my case i have done out with the retarded expensive air cut out valves by making a nice little gasket to block them off, and before hand it was runing a little lean. a little of that was due to leaking intake gaskets. which i took care of that with the air cut outs. as soon as i was done and ready to run i could barely get it to run. so i synced the carbs up manually and got it to fire up, then did it with gauges. well after that i took it for a hard ride and cut her out at wot. yanked the plugs and they were dark brown close to black. which means its running really rich if im correct. did the same thing at different throttle positions and even idling. idle was the only time it was running nice tanish grey.

i also have old gm style car coils on it due to the factory ones being weak and the gap to around 45 like i would on a chevy v8 would these coils cause it to burn the fuel more efficiently causing my free flowing set up to burn rich?

any help or input will be taken and appreciated thanks guys
 
Blocking the air cut valves will make it run rich all the time, they are only supposed to operate at high vacuum (closed throttle on overrun)
You would be better off just fitting the cover plates and letting it afterfire
You need to do some research on how those carbs work
 
i was under the assumption that they only functioned on deceleration, and blocking them off would only cause it to be lean on decel, but it has had the complete opposite affects. i had a 450 with factory carbs that didn't have the ugly cut out on the side and they functioned awesomely. so at the moment i like that its running a little over rich with the open pipes and carbs. i just need to know i its gonna all of a sudden lean the crap out o it. which your reply assures me is shouldn't. thanks for your response
 
Can you post of pics of exact what you have done? I looked at a set of 500t carbs and they look just like my 450k carbs. I may be confused by you terminology.
 
Theres an air cut valve on the side, around 3/4" dia
It closes during decel to richen mixture slightly ('cuts' one of the two pilot jet air passages)
Honda first introduced it around 1977
It frequently gets mistaken for an accelerator pump by people who don't understand carbs (has a diaphragm and plunger but no mechanical connection to throttle)
 
ahhh i see, i thought it opened on deceleration. like you had said before, i guess i need to look up exactly how it functions, cuz i think that may be why my idle adjustment screws basically do nothing. seems as i should only block of the air passage to the diaphragm. then i'll be able to use my bigger jets i recently got and haven't had to use yet :D thanks pj much apreciated
 
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