October 4, 201312 yr Hi guys, rode my bike for the first time today and i noticed something wrong.... A)My bike doesnt fell torky, firm, and safe... Throttle response is slw when in low rpm range and has some kind of slack (not cable slack....id rather call it lag or latency...throttle opens but takes longer than usual to the engine to respond) B)Stalls when pointing downhill or when riding a stoppie C)Huge fuel consumption D)Fuel leaking (thought it was a miinor leak when in odd angles... but its not minor at all) I really think i have a fuel level problem in the carb... Seems like the float isnt working propperly and floods my intake when the bike leans forward.... Some of the gas is spilled out, and some other goes to theengine intake...thats why its running rich at low rpm and feels boggy and lazy.... Correct me if im wrong, any suggestions is appreciated.... Anyone else had this kind of problems in their EVO??? (I read here that some other Betas had the same setup problem when new)
October 4, 201312 yr Xeriotti This topic has been covered SOOOOO many times before. Try and find the article I wrote on this about ten years ago posted on here somewhere. The solution I presented back then has been used by Dan and others to much success (jump in Dan).
October 4, 201312 yr The fuel cap could only fail to vent negative pressure which would cause a lean condition correct? This sounds like the needle is not sealing, high fuel level and over fueling Pull carb, clean, inspect the needle and seat
October 4, 201312 yr Author Took the bike bike apart... resetted the level but still doing pretty much the same, im waiting the bike to cool down and ill try to lower the level even more.... Im asking... IHow much can you guys point your bike "nose down" before engine stalls due to fuel overflow??? If i lift my rear wheel (by hand) like 2 feet it bogs and stalls..... :S The rest seems to be fine, on the flat the bike runs pretty well.....
October 4, 201312 yr Author Well, i tried to fix the carb level problem.... I took the carb apart and bent the float to achieve the desired angle when fully closed... I did it two times, giving more angle and noticing an improvement each time.... Its actually assembled like this. Improved a bit.. But if i leave the bikes rear wheel on a 40cm ledge and the front in the ground it bogs and stalls.... Open needle. Contact point between needle and seat. Shuts fuel (maybe not supertight, but tried blowing air thru the fuel line and shuts pretty much tight) -Notice that level is even lower than reccommended by the Lampkin tutorial... Float is more than parallell with carburetor body, so level is even lower and it keeps doing pretty much the same (improved a little but still not rideable in a downward slope....need to be revd up high to keep running) Needle fully closed with spring compressed by the float weight... float parallel to carbs body in this case. Its 2PM here... Ill take the carb out AGAIN.... and will try with even less fuel level on the float, I already hated 2 strokes, Now im starting to hate trials, and motorcycles in general jajajaja Its my first brand new bike ever... Im glad i always bought used or wrecked bikes... never had problem with those...
October 4, 201312 yr Author Guys, i solved the problem.... I increased the level even more.... and now runs perfect with no bogging or stalling even at extreme angles... I didnt take pictures of the carb when ready, but its like picture 2, when carb is upside down....
October 5, 201312 yr Bit Late but you did see the Pinned topic about the Kehin at the top of the Beta section? http://www.trialscen...th-keihin-carb/ Edited October 5, 201312 yr by telecat
October 5, 201312 yr Author Telecat!!! Ive seen the tutorial, but i needed to give it way less fuel level to make it work propperly.... Maybe a shorter needle or less stiff needle spring...variables are endless.... I tried as describes in the tutorial, but had the same problem....i took it apart 4 times giving more fuel level each time till i got to the desired performance....
October 5, 201312 yr I think the problem may have been the angle of the float tang to the float valve . It needs to be near 90 degrees a point of fuel flow shut off
October 6, 201312 yr Author I got bad news.... With little fuel on the tank (when i fixed the problem a couple days ago) it worked propperly, but yesterday i topped the tank and kept doing the same bogging overflowing thing.... I guess it needs a little less "level" so the float, actually floating on the gas will have more leverage to propperly push the needle against the seat, sealing tight even with the pressure generated by the gravity of those 2.6 liters of fuel on the tank... Its sunday midday... ill take a cocoa to be calm, then im heading to the workshop to fix this...(or at least try)
October 6, 201312 yr For what it's worth, from a point of view, I have seen this at least a hundred times Fuel overflows, customer changes float height, sometimes several times with minor improvements The reason the problem is not solved is that float height was not the cause in the first place - bending the tang does NOT increase the leverage and sealing ability of the needle.......EVER - lower fuel level cannot be attained if the needle is leaking, it just changes the time t takes for the problem to occur If a carb is leaking, it is never the float height, it's that the needle is not sealing, perhaps the carb casting is not right, perhaps the needle is not right, perhaps the float is sticking, but certainly adjusting float height is not working and the next thing that could happen is the float height will be so low you could cause a lean seizure
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