AV7 PHBG Gas leak

M∆®†Y Køk€š /

So here's kinda what I've got going on...

Moby 50v with 19mm dellorto PHBG clamp mount with shorty intake (AV7). I've got a lot of performance related parts on it, but I think they might be irrelevant to the problem I'm having.

Basically the bike rips, but I go around the block once and my temp is 400F+. When I'm riding it takes off without any issue and gets up to speed and then i can can feel the power cut out and come back it sporadically. I look down at the carb and I've got gas coming out of the overflow/drain spigots. I believe that something is causing my gas to fly out the drains and it's starving the float bowl and maaking the bike lean out, thus the bogging and hi-temps.

I've taking the carb apart and the float needle looks fine, I flip the carb upside down with the float bowl off and the floats are horizontal with the edge of the carb base. When the bike sits with the petcock open no gas overflows out of the carb. Everything seems to be fine. So I'm at kind of a loss, anything you guys suggest I check next?

Re: AV7 PHBG Gas leak

Take her out for a rip and check the plug colour after a nice hard intermittent run. If the colour looks right even though it was breaking up then it might be more ignition then actually fuel. Where is your timing set?

Re: AV7 PHBG Gas leak

M∆®†Y Køk€š /

I'm running the MVT premium CDI and I've got it set to 1.5mm BTDC. After seeing all the bad reviews the mvt is receiving lately that has me a little worried.

Re: AV7 PHBG Gas leak

i like waffles /

i know somebody else who had the gas flying out problem, i think its the result of extra vibrations and such, which dont really let the float needle seat all the way, letting extra gas in, and then overflowing. they do sell a heavier float i believe, but i think it only made it lose less gas. im betting ya got two problems, the carb overflowing, and the timing thing like REbel Mody suggested. id lower the timing, maybe keep yer kit from gettin so hot!

Re: AV7 PHBG Gas leak

If you have a lot of vibrations then the fuel will percolate and will get very wet. There is the heavier float, also check if it has the anti perc disc between the jet and the emulsion tube, lots of people remove that little disc for what ever reason.

Re: AV7 PHBG Gas leak

M∆®†Y Køk€š /

I do have a lot of vibration, it's been like a year since it's been in running order though so I don't really have a really good frame of reference. I figured, "hmm maybe it was like this before too..."

Thanks a bunch guys, I was running out of ideas. Two more things to check now!

Re: AV7 PHBG Gas leak

timing and jetting cured those same symptoms on my kitted 50v

Re: AV7 PHBG Gas leak

M∆®†Y Køk€š /

Finally started wrenching on this again and made a video of what's going on....

...and I just noticed rebel moby's comment about the anti-perc disc which I did remove, sigh. I'll throw one in and see how it goes.

Re: AV7 PHBG Gas leak

The left silent block looks soft - like it distorts under engine torque and then stays pulled back and down a bit.

Looks like percing the fuel which will also effect the mixture going to the combustion chamber if the jets are delivering fuel and air rather then just fuel.

Re: AV7 PHBG Gas leak

Rebel is right. The left bushing seems to always be the first one to go. Sick looking bike. i love the green

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account