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Bob Kelly · 01-18-2022, 04:55 AM

Hard to say with the little discription you have given on how it runs !
my guess is that it is running good but later on in the ride it starts to starve for fuel
there for as the other guy said fuel vent is probably not venting from the gas tank
I concur with that assessment ! it's also possible that your float level is set a bit low
I would quit using your shed weed till you figure out the bike, before you cook it ! and seize a piston !
larger pilot jet is ONLY if the engine needs it to idle correctly
larger main jet is needed only if your running lean at WOT ( wide open throttle)
no "I think it will need it" ideas work here, so put the stock jets back in it and assess
if it needs it.... it may not ! you do not put in new jets just because you put on new air filters Some times it is needed but only some times Opening up the exhaust usually does mean jetting changes because they have the engines so de-tuned to pass emission standards now days..... but making changes to the carburetor without knowing which way to go or a reason to do it is totally folly !
put the stock jets back in and then tell us how it runs down to the last nitty gritty detail
...for example ...there is a slight pause when it comes off of idle when I give it throttle ( too small pilot jet or simply not adjusted correctly)
or it takes off great until i reach mid RPMs and it slows down accelerating (too small main jet)
and what is the color check of the plug looking like ? is it white, brown or black ?
yes you must pull the spark plug and look at it to see <GRIN>
a carburetor works somewhat like this.... at idle speed your fuel is regulated by the pilot jet and fuel air screw, at mid range RPM it's working off the needle jet ,jet needle and throttle valve cutaway, at wide open throttle and top RPM's it's solely on the main jet.
.... this is a close approximation and each carb works a bit differently from any other but the principal is correct the carburetor is made in such a way that all 3 of those settings interact with each other as well so the transition between just off idle and into mid range there is a grey area where both are working to provide the correct fuel air ratio and the same goes for when the jet needle is all the way up that transition period needs to be a smooth one ...
do a plug color check when you notice the running low on power (Stop it right then and pull the plug) I almost bet you it will be very white.... and that is unhealthy for your engine !
....Bob....

01-18-2022, 04:55 AM	#4
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	Hard to say with the little discription you have given on how it runs ! my guess is that it is running good but later on in the ride it starts to starve for fuel there for as the other guy said fuel vent is probably not venting from the gas tank I concur with that assessment ! it's also possible that your float level is set a bit low I would quit using your shed weed till you figure out the bike, before you cook it ! and seize a piston ! larger pilot jet is ONLY if the engine needs it to idle correctly larger main jet is needed only if your running lean at WOT ( wide open throttle) no "I think it will need it" ideas work here, so put the stock jets back in it and assess if it needs it.... it may not ! you do not put in new jets just because you put on new air filters Some times it is needed but only some times Opening up the exhaust usually does mean jetting changes because they have the engines so de-tuned to pass emission standards now days..... but making changes to the carburetor without knowing which way to go or a reason to do it is totally folly ! put the stock jets back in and then tell us how it runs down to the last nitty gritty detail ...for example ...there is a slight pause when it comes off of idle when I give it throttle ( too small pilot jet or simply not adjusted correctly) or it takes off great until i reach mid RPMs and it slows down accelerating (too small main jet) and what is the color check of the plug looking like ? is it white, brown or black ? yes you must pull the spark plug and look at it to see <GRIN> a carburetor works somewhat like this.... at idle speed your fuel is regulated by the pilot jet and fuel air screw, at mid range RPM it's working off the needle jet ,jet needle and throttle valve cutaway, at wide open throttle and top RPM's it's solely on the main jet. .... this is a close approximation and each carb works a bit differently from any other but the principal is correct the carburetor is made in such a way that all 3 of those settings interact with each other as well so the transition between just off idle and into mid range there is a grey area where both are working to provide the correct fuel air ratio and the same goes for when the jet needle is all the way up that transition period needs to be a smooth one ... do a plug color check when you notice the running low on power (Stop it right then and pull the plug) I almost bet you it will be very white.... and that is unhealthy for your engine ! ....Bob.... __________________ It's too late when you've gone too far !
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