Question1983 Honda Ascot VT500 when bike is running "or not" with gas tank petcock open gas leaks into crankcase. Bike starts and runs good no other problems. Bike did sit unused for 5-10yrs.
AnswerRoy, the whole fuel system needs to be checked, cleaned and secured with new parts.
The vacuum petcock diaphragms can rupture and allow fuel to pass through the diaphragm, into the small vacuum line and back into the intake manifold connection, where it can go down the intake valve and soak the piston, causing a hydraulic lock in severe situations. The petcock needs to be removed so the screen inside the tank can be cleaned and checked for damage. If there is rust in the tank, it needs to be neutralized and/or the tank coated. There are aftermarket sources for the carburetor and petcock parts. Check with Sirius Consolidated in Canada for spares.
http://www.cmsnl.com/honda-vt500ft-ascot-1983-us_model1128/partslist/F++1401.htm...
The carburetor float valves need to be cleaned and checked. Leaking float valves will overflow the bowls, usually causing fuel to leak out of the overflow tubes on the float bowls. If those are stopped up, then the fuel can run down the intake manifold runners. Remove the carburetors and have them cleaned and all gaskets, o-rings replaced.
Fix the fuel system, then drain the oil and change the filter to purge the contaminated oil in the crankcase. Be careful, as this can be very flammable. A stray spark or backfire can start a fire or worse.
Bill Silver
1984 VT500FT owner, too!
