Blowback Through Gas Tank- Tight Valves?

KentuckyDonkey · 10-14-2009, 12:04 PM

Hey Everybody!

I've never thought that the engine on my Vbike 300 "Monster" sounded quite right- and I've noticed, if you take the gas cap off while it's running, you can feel air coming out of the tank. Must be getting blowback from the fuel line. The only thing I can think of that might cause such a condition, is the valves being too tightly adjusted from the factory. What doi you all think? Any other ideas? Anyone know the valve adjustment specs for this 300cc Loncin motor? (Just asking before I go ahead and try loosening them somewhat at random).

Cal25 · 10-14-2009, 12:16 PM

If it is blowing air up the fuel line, how would the fuel get to the carb?

A clear piece of fuel line would confirm what is going on.

KentuckyDonkey · 10-14-2009, 12:54 PM

That's a good question, Cal- but where else could it be coming from, as the fuel line is the only possibility?

10-14-2009, 12:04 PM	#1
KentuckyDonkey Join Date: Feb 2009 Posts: 331	Blowback Through Gas Tank- Tight Valves? Hey Everybody! I've never thought that the engine on my Vbike 300 "Monster" sounded quite right- and I've noticed, if you take the gas cap off while it's running, you can feel air coming out of the tank. Must be getting blowback from the fuel line. The only thing I can think of that might cause such a condition, is the valves being too tightly adjusted from the factory. What doi you all think? Any other ideas? Anyone know the valve adjustment specs for this 300cc Loncin motor? (Just asking before I go ahead and try loosening them somewhat at random).
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10-14-2009, 12:16 PM	#2
Cal25 Join Date: Feb 2008 Location: Terrell and Grapevine Tx. Posts: 1,585	If it is blowing air up the fuel line, how would the fuel get to the carb? A clear piece of fuel line would confirm what is going on.
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10-14-2009, 12:54 PM	#3
KentuckyDonkey Join Date: Feb 2009 Posts: 331	That's a good question, Cal- but where else could it be coming from, as the fuel line is the only possibility?
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