Hi lads got an 03 280 pro it's pressurising The gearbox and pushing oil put of breather behind sprocket. It's just had a full rebuild. New crank bearings/seals. Piston and full faster set. I'm confident crank seals are ok Is there another reason it may happen oil level is correct.maybe it waa a weak seal. Would,just like some feedback before I remove engine and strip it again.

The bolt that holds on the primary gear (clutch Assembly) is supposed to be hollow for oil flow. If is just a standard bolt, you can just leave it out. Yes you can, or at least till you get a replacement. It`s like a 5mm allen.

Hopefully the crank seals are fitted the correct way round. As mentioned, there is a small hole driiled through the clutch retaining countersunk allen bolt, ensure it is not blocked. Recently the same bolt became loose on my bike and caused no problems other than the clutch lever to intermittently lock solid half way through its stroke.

Will the engine actually be able to breath with a normal allen bold? Because the breather is actually behind the clutch and the shaft. So I can imagine it does overpressure, but then it cannot go trough the tube imo.

Is there a lot comming out of it?

I have it somethimes that its only a little when it has been on its side for a while (for maintance or so).

Edited December 23, 201411 yr by crazybond700

The clutch centre bolt is an M5 cap screw with a centre hole. Generally, if oil is being forced out of the breather, then this bolt must be in place for this to happen. The problem for pressurising the case will likely be the centre gasket or the crank case bearing seals fitted the wrong way around, or the crank shaft O ring seals are passing. If you are doing the work yourself, take care when fitting the LHS main bearing as the oil holes must line up, make a mark with a felt pen on the case where the oil hole should align up to.

With the oil seals, the spring side faces the pressure.

Bye, PeterB.

Thanks for all help. I'm almost sure everything was right the,only thing.I can't say for sure is that the Allen bolt has a hole in it I didn't pay attention to that altho I should have.

Seeing. As that's the easbestos I will try that first if it doesn't work il order full gasket set and do some ripping.

Happy Christmas to all

Got it sorted today. I removed the bolt in the centre of clutch drilled it out because I couldn't find original.not it's working perfect.I'm running atf fluid in trany and it really foams up.should I justly run normal oil instead?