GT 550 oil issue

[Clarkie_10]

Hi Can anybody shed some light please ?

when I park up my bike for sometime , the 2 stroke oil tank seems to drain !! ( ie oil level drops )

I then find unburnt oil leaking from crankcase gasket .

Is it possible that something wrong with the oil pump as I would'nt expect this when engine not running .

I'm going to have new crank seals fitted soon as I know one weeping , would knowledgable folk recommend replacing any other items around the SRIS system whilst it out of the bike .

Your thoughts are very welcome .

[GTandcbr]

Oil in the tank is fed by gravity down a pipe to the pump. There is a banjo that bolts to the pump side. Check there is not a leak top or bottom of that hose. Oil then fills the pump. There are six small rubber o rings that seal the pump to the spider at its base. Check there is no leak from the base of the pump or the cap of the pump where there is a paper gasket. The oil lines that come from the spider at the bottom of the pump are nylon and can split just check for leaks. On the end of each pipe (3 to the crank and 3 to the cylinders) there is a brass banjo. This serves two purposes. When the engine is running , a valve inside the banjo which consists of a spring with a ball bearing on it, allows oil to flow from the pump to the engine. Then when the engine stops the spring seals the valve to prevent oil from continuing to flow into the engine with gravity pressure. I suspect this is where your fault is. Now there is more at stake than loss of your 2t oil. If the crankcase fills enough it can cause hydraulic lock( ie the piston is pushed down the the explosion in the cylinder but because of the oil it cant. This usually bends the conrod and does other damage.
So it is essential to rectify the problem immediately

[jabcb]

Where is it leaking from the crankcase gasket?

[Alan H]

Where is it leaking from the crankcase gasket?

There isn't a gasket on the crankcase. If yours has, that's why it leaks.

[jabcb]

Perhaps a better question would be: where does it look like its leaking from?

My GT380 tinkering project looked like it was leaking two stroke oil from a crack in the crankcase.
Turned out it was leaking from an oil line near the SRIS line passage through the crankcase.
The oil was running down that passage and dripping from several spots on the crankcase.
But there was hardly any visible evidence of the leak near the oil line.

[Craig380]

It sounds like it could be from the base gasket, but it would only leak from there at a VERY slow rate ...