Gas in crankcase

[drewandkellie]

I was having trouble starting my stock 1980 GS1100E (10K miles). The starter was freezing up. I believe it to be a bad starter clutch. I tried to bump start it, and when I did I heard a bang and mist shot out the side of the motor by cyclinder #1. I can't tell where it came from. I tried bump starting again and it started up. I thought all was fine till I headed down the road. I felt the back end sliding. I looked down and oil was evrywhere, covering the pipes, side and back of the motor and the entire back wheel.
The motor however ran ok. I headed home and shut it down.
I found oil in the air box, oil covering the the motor behind the cylinders, and some oil on the front of ther motor near cylinder #1.

I checked the oil window and it was way over full, drained out the oil and found over six quarts of oil and gas. I stripped down the motor last night to the pistons and all seems ok on the initial check. I have several questions:.

1 How did all that Gas get in the oil? I sometimes leave my pingel valve on but could all that gas get from the tank to the crankcase by just leaking through the carbs, nothing leaked out onto the floor from the carb overflows.

2. where did all that oil leak from when I rode bike. Cylinder head gasket? base gasket? breather on top of the rocker box to the airbox? out of the carbs?

I will have the cylinder and pistons checked to see if they need replacing bu with 10K original miles I am asuming they are not going to be bad. I will also do the starter clutch.

any ideas before I continue on?

[Nessism]

A stuck open float needle will allow the carb to over flow and the gas will flow into the intake port, into the cylinder, past the rings and into the crankcase. Oil/fuel mixture will often times excape the engine from the breather port on top of the valve cover and wind up in the airbox. Most of the time a simple oil change takes care of the engine but in your case, it sounds like you blew out a gasket. Needless to say, your carbs need attention to find the offending float needle/seat.

[drewandkellie]

That sounds reasonable to me. I will keep checking and keep you posted.
any opinion on gaskets, should I use suzuki gaskets or after manrket?

[rapidray]

For a STOCK rebuild ALWAYS use Suzuki stock gaskets. If the bike has never had the head off before, make sure you change the valve seals & hone & re-ring the cylinders while it's apart. Good luck, & remember to turn your fuel valve OFF when you park the bike. Ray.

[Fast Doc]

Your petcock vacuum auto turn-off feature must have failed. You'll need to replace or rebuild the petcock also.

Good luck, hope the project goes smoothly and quickly.

While it's apart I'd have the head done, replace the base O rings, and hone the cylinders and fit new rings.

Also inspect the clutch fiber plates. I wonder if the gas could have damaged them.

[drewandkellie]

final conclusion

sure enough, it was what is known around here as "static lock". Gas filling the crankcase when the petcock was left on. It Blew out due to the hydraulic pressure of too much fluid under the pistons. I used Suzuki Parts and changed the base Gasket, rings, head gasket and all the necesary o-rings. I took My time and did it over the past few weeks. Installed a Vance and hines header and with stock jets, air box, filter and cover she runs fine. No popping or spotting (I'll keep an eye on the plugs). These days I shut off the pingel valve every single time the bike is shut off, even for fill ups ant the pump. Put and inline gas filter in and so far My beloved 1100E is healthy again. Thanks for all the help once again Guys.

[bwringer]

This is why replacing the vacuum operated petcock with a manual petcock is such a bad idea.

The stock needles and seats aren't designed to hold back a tankful of gas indefinitely. Even if they're not stuck open and everything is in perfect shape, gas will eventually trickle into the crankcase after a day or two if a manual petcock is left "on" or a vacuum petcock is left in "prime".

If your original petcock is bad, replace it with a new one from Suzuki and ride happy for another 20 years. There's nothing at all wrong, deficient, or unreliable about the design, other than it "only" lasts about two decades.

If you have an absolutely infallible memory and don't mind spending double what a new OEM petcock costs, then sure, go ahead and get a Pingel, Rain Man.

I'm an excellent rider. Yeaaaaahhh. Definitely an excellent rider.