My 250 when started from cold ( which is a pain) blows a lot of oil out of the exhaust 

 

pretty sure urge it's not from the mixture because of the quantity of it and the fact it won't start easily and I haven't changed mixture or oil. 

 

Thinking its its a gearbox seal is this easy to change and what's involved? 

 

James 

As Tom Jones said 'It's not unusual'... a two stroke will always smoke a bit heavier when it's first fired up and the condensation clearing as the engine starts to warm can look like oil. Is the bike running well once it's at operating temperature? Is there a drop in the gear oil level?

This is some serious oil that comes out, could probs fill a shot glass with it. But it does then calm down once warm.  I have ordered some seals so will have a closer look at it before I strip it down 

my rev 3 200 was like this crank shaft seal dry side IE flywheel stator side had perished badly .

 

Stripped down seals are out and new ones on there way... main bearings feel like they have a lot of play in but my bike doesn't sound rough when running, 

If they need doing think thats a bit out of my depth, is there anyone around who will do a engine refresh if i posted them the engine?

 

my exhaust was also full of watery oil (i submerged it last ride out  ) i have left the exhaust hanging upside down in the garage dripping away, any other way of cleaning it out?

Think it was a bit of both gear oil and build up of 2 stroke oil 

If you didn't get the motor hot enough to dry the exhaust out properly after submerging it chances are you're going to need main bearings soon.

Is the play in/out with the primary gear off or up/down? Up/down is worn out, the primary gear being tightened up should remove in/out play

Replacing main bearings isn't the worst job as long as you take your time, biggest thing to be careful of is the gearbox. The whole job is in 1 of the links pinned at the top of the section

Yes seems alot of play up and down so it needs doing 

 

 

I have rebuilt one of these before but struggled getting the piston and rings back in..... also dont you have to double up the base gaskets or something?

 

Shouldn't need to double up on gaskets, I think that was a much later bike that had different thickness gaskets to alter squish gap to the head & also port height

I've always removed head & cylinder in 1 piece rather than needing to replace the o-rings between the 2.

Fitting the cylinder over the rings isn't hard but that is all down to making sure the gaps are centred over the locating pins before you start.

Use something under the piston to hold it steady then lower the cylinder over the piston while pressing in on the rings through the gap in the transfer ports, you can twist the cylinder a small amount to make the rings sit around the locating pins if needed, compress the lower ring the same way & the cylinder should slide down to whatever you used to stop the piston rocking