Gas in my oil...??

[EasyE]

Just purchased a 78 xs recently and only had it on the road a few times and when it wouldnt start up today...may have flooded it. Tried a couple hours later and nothing. Was just going over everything and noticed that the oil smelt like gas... Whats with that?? Like I said this is my first bike so I'm not too familiar with the machine but very mechanical and just need some knowhow.

I'd appreciate all input..thanks

 

[kindest]

sounds like your petcock failed to work right w/ conjunction of carbs. Seems like it happens frequently with old bikes like ours. Dump that oil promptly. Some people add an inline shut off valve to their gas line to prevent this.

 

[1979XS4002-F]

As stated above the gas can come from your floats sticking or from severe flooding and the gas leaking by the rings... You should really drain/flush your oil and replace the oil filter because the gas can thin out/breakdown your oil severly and damage the engine. Before you refill the oil make sure to verify the carb float height to prevent it from happening again..as well as cleaning the points/gapping and verifying spark plugs are clean and firing well to prevent flooding. You may want to do a compression test as well just to verify your not leaking gas past the rings.

 

[EasyE]

Thanks for the input guys
Very helpful

 

[jmd_forest]

Easy,

For this to happen you need 2 simultaneous failures to occur:

1) petcock vacuum valve failed and allowed gas to flow past petcock while engine is not running (or petcock accidentally left on PRI)

2) float valves in carb sticking open allowing gas flowing past failed petcock to overflow float bowls. (Other possibility is the float may have a pinhole and fills up with gas and will not "float")

Generally, to remedy this both failures should be repaired. Often simply pulling apart the petcock and cleaning and polishing the mating surfaces and retensioning the spring while seating the o-ring properly will resolve the petcock problem but the o-ring and/or vacuum diaphram may be bad. The float valves are cheap and easily available to replace. It might be good policy to rebuild/replace both petcock and float valves in a 35 year old bike to ensure long term reliability.