so i was riding to work the other day and as i was nearing 70 getting in the HOV lane i went to accelerate but had no throttle response. it was basically like going full throttle was just keeping the engine alive. so i pulled off and filled up since i was low on gas thinking this would fix the issue. Even after the fill up i was still experiencing very little power at full throttle. So i got my buddy to bring the bike back in his truck and as i was examining the fuel and air flows to make sure there were no blocks i found that my main valve from the gas tank to the carb tubes was not allowing fuel to go through. I cleaned it out as much as i could however i believe the valve is shot i';m still not getting any flow but i know this is the problem since i filled the card tubes up with fuel with the tank off and the engine ran fine. Does anyone have any suggestions on how to fix the valve since new ones cost 170 pls shipping. i was thinking of eliminating the valve all together by putting a large fuel line directly on the tank to a simple on off valve then to the carbs. i'd just be sure to shut the valve off while i'm not riding to make sure not to flood the carbs.

 

I dont think that if u just open the valve that fuel comes out. I was gonna drain my tank (because im restoring it) but i had to tip the tank over to get all the fuel out. It has to have a vaccum to let fuel out. (I think)

 

well i'm not sure if fuel is suppose to flow freely because of that vacuum on the back. when i first got the bike and was painting the tank i would turn the valve off but there would still be some drips, that isnt happening anymore. plus i did put it all back together with the vacuum tube connected to the back and still having the same problem.

 

Im pretty sure its not supposed to leak. Let some other people reply to this. Im 99% sure though.

 

Hey i seen someone have the same problem. I just remembered what it was. They had a vacuum accuring on the gas tank. Take the gas lid off and ride ur bike around. See if this helps. There could be to much of a vacuum on the tank.

 

There are 2 ports on the petcock. The larger is for the fuel. The smaller is for the vacuum line. If there is no vacuum on, then the fuel will not flow freely from the tank (and should not). A test, is to duct tape a vacuum cleaner hose to the smaller port and turn it on. Gas will then come out freely.

 

well i seem to have eliminated my first thought of it being the petcock. i was searching online and read that you can invert the spring to the opposite side on the rubber stopper to bypass the vacuum and just have free fuel flow. so that worked out and fuel is flowing freely but the engine once it starts is lacking power, sounding really throaty, and dies on take off. the air filter seems like it could use a replacement but i dont think thats the problem. next thing is to take apart the carbs and clean them out, however i've never done that before so it'll be a learning experience to say the least.

 

now i'm running into a small problem trying to remove the carb assembly. i followed the service manual on removal and i loosened the insulation bands but i cant get the assembly to come off. anybody else have this problem before?

 

all there is, is the four bands... once there loose they shopuld come off... if its first time the carbs have been off in a while sometimes it takes some wiggling and force... use a screw driver to get some leverage if needed... Also it sounds like ur needle valves arent adjusted right in the carb if u lack power at full throttle

 

Yeah, the first time can be a real knucklebuster until you figure out the amount of force required. After loosening the lower bands, I pushed mine forwarded and then started pulling. It took a LOT of effort to get them off the first time.