| Author | Message | ||
     The4ork |
first off... had the bike running perfect, i spent a whole day tuning the carb in, shimming the needle just right and all that. but recently ive been getting a progressively worse problem with the bike, that i believe to be carb related. the problem is first noticeable when the bike has not fully warmed up yet, and the choke is stil out. i usually drive the bike easy for the first few miles to let it warm up. but after that if i try to get on the throttle, anything more than about 1/2" throttle it looses all power, no popping or nothing, just brrrrrr.... and usually if i give it wide open throttle it will come back to life. hmmm maybe its too rich? im thinking.... so i push the choke in, it just flat dies then... pull the choke back out runs ok... hmm maybe im lean? my next step would be to pop the carb open again and replace the slow jet with a larger one, but im already running a 48 in there... i dont have the next size up, but does anyone have any clue why all the sudden i would need a bigger slow jet? maybe something to do with the atmo pressure and humidity? (been really humid with lots of rain since i tuned it) usually after fully warmed up it does not have this problem, but sometimes it takes a REALLY long time before it starts running fine. and also ive noticed its the worst when the bike is HOT, i.e lots of stop and go traffic and red lights... grrr! | ||
| Ratbuell |
More info needed. Stock engine? Exhaust? Main jet size? Turns out on mix screw? Both my tubers - both thunderstorm engines, factory on the S1W, personally converted top end on the S2 - run 190 mains, 2.5 turns out on the screw, and the S1W runs a 48 slow with the full race exhaust (header and muffler) while the S2 with stock 2" header and race muffler likes a 45 slow. To me...it sounds like you might have a float bowl issue and you're fuel-starved for some reason. Make sure you didn't kink the fuel line and doublecheck your float needle / float height adjustment. Also - and I just went through this on her M2L - make sure your accelerator pump needle (yes, there's a needle in there) isn't stuck and you actually get a squirt when you twist the throttle. FWIW, I have a set of hobby-shop dental picks that I keep in the garage for carb work. I can get larger debris out of passages and jets with no problem, it makes life MUCH easier! | ||
| Guell |
I think hes running stage 3 xb heads | ||
| The4ork |
stg3 XB heads, stock cams, stock header, v&h exhaust, 190 main, 48 slow, havent touch the mixture screw, 2 shims on the needle (i think) and the accelerator pump is working. today i rode it, and was doing the same thing, i went WOT and it just went Brrrrrrr.... twist the throttle a few times and went WOT again (engaging the accel pump) and it caughed and went to full power (resulting in an accidental wheelie in front of a cop) its getting annoying lol i def. wouldnt take it out on a mnt run as it sits right now, i cant trust the engine | ||
| Ratbuell |
Intake seals? And check that mix screw...with those heads you may need to go an extra .5 turns out or so. Just a WAG. | ||
| Rjn |
first off i'm no carb expert, but before you pull apart the carb isn't it easier to first check your fuell filter and fuell line or that vacuum breaker hose on top off the tank?? since you had it running OK before!! | ||
| Buellistic |
SLIDE DIAPHRAGM ??? | ||
| Rickie_d |
Are all the vacumm ports (2) capped off or connected (the top one) to the VOES? | ||
| The4ork |
one is plugged, one is connected to some kind of sensor. slide diaphram was in perfect shape a few months ago, and i dunno what i should do with the mix screw | ||
| Ratbuell |
Turn the mix screw all the way in, gently. Then back it out 2.5 turns as a starting point.If your issue changes...you've found your problem and can go from there. Out = richer, in = leaner. | ||
| The4ork |
i put in a new tank of 91 and a whole bottle of fuel injector/carburetor gas treatment and now it runs flawless... | ||
| Rjn |
So maybe you had a debry in the old tank ? Maybe an idea to put an extra fuelfilter in between the petcock and carb. Had a similiar problem with my bike, and i run it now with an extra BMW injection fuelfilter in between. No more problems ever since with the carb. |
