[Dirtdevil06]

Either way the heads going to have to come off isn't it .i was wondering if the quick start up and little run round work and then turned it off damaged the oil ring .it has compression but if a little oil is getting past that would bring the compression up .she still starts first kick just wants to be a two stroke at the moment .nothing really looks oil fouled unless like you said about the oil seals its leaking down the exhaust valves and burning in the exhaust it doesn't really clear though .

[JimDirt]

It would be nice to be able to localize the problem so when tearing it down , at least you have a goal , instead of just rummaging around hoping to find the issue , but its either rings or seals , so at least you have something to look at , but its still not really narrowed down

[Back2-2]

Not sure if you have already done this but - Check the gear case vent line and the valve cover vent line. If they becomes clogged or pinched it can back pressure and force oil into the engine.

Blue smoke is Oil, Black smoke is Fuel.

Just a little things to check.

[Dirtdevil06]

I did use different pump fuel 97 Ron octane I have checked the breathers the gearbox breather did look like it had a slight kink but blew through it and seemed ok .

[Back2-2]

I did use different pump fuel 97 Ron octane I have checked the breathers the gearbox breather did look like it had a slight kink but blew through it and seemed ok .

Good, it was just a thought. There have been others with pinched gear case breathers that had blue [ oil ] smoke issues from back pressure.

No possible way you used pre-mix 2 stroke gas in your bike by accident ? I dump my trials bike mix into the 450 sometimes to use it up. That is only 85:1 mix plus the straight fuel in the tank so I do not see the oil smoke but if it was a heavier mix of 50:1 I suspect you would see some slight blue smoke.

[Dirtdevil06]

It was straight from pump but the fuel felt like it had a film to it .gonna try the fuel if it was that breather how long would you think it would take to burn it off

[Dirtdevil06]

Stripped it all down .the only thing is when i blow threw the gearbox breather i can hear it kind of bubbling in the crank case oil.

[Back2-2]

Stripped it all down .the only thing is when i blow threw the gearbox breather i can hear it kind of bubbling in the crank case oil.

If you hear bubbling, that would indicate the gear case has to much oil / fluid. The breather port is at the top of the gear case and oil level should be considerably lower than that point. Double check case oil level and check coolant level to be sure you do not have a water pump seal leaking coolant into the gear box.

[Dirtdevil06]

I drained the oil out the gearbox before i blew down it and because i dont have a head or barrel on it at the moment i can hear bubbling down near the crankshaft .i put 700ml in the box on the friday and drained it yesterday only about 350-400 ml come out.

[JimDirt]

Check the oil level in the tranny , and see if its overfilled , if so then you have oil migration from the engine to tranny side , which means bad right side bearing seal

[Dirtdevil06]

Only 400 ml come out of the tranny .so im assuming the tranny oil is getting pushed passed the crank seal into the engine .its all in bits now .