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Is this a carb problem or ignition?

1.2K views 5 replies 3 participants last post by  89tang  
#1 ·
I thought i had this problem dealt with i thought it was a spark plug/wire problem cause i had no more problems from the bike. UNTIL today almost got me hit, what it is doing is acting like it's not getting enough fuel, it won't start unless the throttle is all the way open and then it'll only idle at about 1000rpms enough to barely limp you home going about 2mph :mad. If you let off the throttle at all the bike will die. Before it done this i thought it was an ignition problem like something was getting to hot or a wire was messed up. So i replaced the plugs/wires and it didn't do it anymore.

I took the carbs off the bike and nothing is sticking the floats are all working correctly. Although i can see that a couple of them don't seem to be at the same level as the others. It actually looks like someone cleaned everything before. Supposeably the bike has a dynajet kit in it. Also the bike has K&N pods and a kerker exhaust if that makes a difference.

Any help i'd apperciate it.
 
#2 ·
Have you checked the petcock? Remove it from the tank and see if the filter on it is completely gunked up or covered with rust or something. If it's running like it's not getting fuel, then maybe it's not..
You might also want to check that your fuel lines aren't kinked from replacing the tank badly and that they almost always run downwards to the carbs.
 
#3 ·
Sorry should have specified yeah i already checked that stuff. Besides when i took the bowls apart it had plenty of fuel in them so it wasn't running out of fuel. I check the spark too and all the wires have spark..........
 
#4 ·
try running the bike in the 'prime' position, just because you have fuel in the bowls you may not getting enough flow. The above concern about kinking the lines is correct, what usually happen is the 'vacuum' hose is small and gets easily kinked, reducing correct amount of fuel hitting the carbs. If you have the tank off, turn it to prime, and make shure the fuel 'fffffffffffffffllllllllllllllllllllooooowsssss' out, if it does, connect and try riding your bike in the prime position. If it works, your 'petcock is dicked' or the vacuum line is getting pinched or has a chunk of crap in it.
 
#5 ·
So your saying just because my bowls were completely full it could still be running out of fuel:confused.

Anyways there are no kinks in any of the lines, infact when i was syncing the carbs a few weeks ago i cut the fuel lines down to prevent kinking. Vaccum line isn't kinking either it's pretty hard rubber it would be hard to kink it easily.

As for the petcock, could it be the the petcock is flowing to much fuel and flooding the motor out? Cause i did have an issue with the petcock that i thought i fixed, but when i had the tank off the last time and i noticed last night when i was going through the carbs that the petcock was leaking gas not constantly but it would leak a puddle on the ground and stop. Maybe the petcock is screwed up then but when in prime and when i suck on the vaccum line they flows really good.

Today i got into the carbs and cleaned them the best i could they were already pretty clean. But the floats were not all the same level, and i reset the idle mixture screw those were all out of wack too.
 
#6 ·
Alittle update, i worked on the carbs quite abit over the last week and ahalf. No. 2 and 4 cylinder's were running way to rich, so much so that the plug was fried and no spark was being produced. Header pipe leading from those cylinder's were cold telling me they were firing at all. I dialed in the idle mix screw's and got it idling just about right 1000-1200rpm. It's still got a slight stumble if you crack the throttle at idle though i think it might need another adjustment on the screw but it smells pretty rich as it is so i'm gonna leave it. Could also be the pods that are on it i suppose.

I adjusted the float height also, modified the petcock cause i was having a problem with it closing back up but no problem with it flowing fuel. Either way i put some valves on the fuel lines so i could close everything so it wouldn't get down in the crankcase.

Overall though the bike seems to be running alot better i've pretty much got rid of the hesitation from 2000rpm to 4000rpm runs alot smoother in those RPM ranges. Throttle response has improved 100% throughout the RPM range. HOPEFULLY it'll stay running for me now when i go to take it for a spin around town lol.