Thanks for the update.Let us know how the seals work out and if she fires.I think I,m going to look for a set of ice tires for the Ossa to play on this wnter.

Got around to installing the new crank oil seals. No luck on starting up though. Poor compression seems to be the issue but I can't figure out why.

- New piston and and bored out cylinder

- New cylinder base gasket

- New crank oil seals

Sprayed WD40 on all case matings looking for air leaks. Nothing noticable. Back at it tomorrow for some more investigating.

Some pictures from the crank oil seal install.

Edited July 16, 201511 yr by christiank

Did you remember the O ring that goes on the crankshaft behind the spacer behind the primary drive sprocket  and weight. If you have then that should be fine. Graham.

Per Graham (O-Ring), when you say "poor compression" this is hard to understand with a fresh 325,

cant tell from the photos whether the primary side seal retainer holds 1 or 2 seals (1 spring to crank/ 1 to clutch side),

the next thing is a pressure test , you would think the thing would a least fire with a little fuel down the spark plug hole.

I believe I can find a photo of Saw Millers pressure set up.

Good luck

 

Larry

Graham - The o-ring on the crankshaft behind the seal and spacer is in there. I didn't inspect it closely but it looked intact.

Edited July 16, 201511 yr by christiank

It just doesn't seem like there is much resistance when kicking it. Almost like there is no difference with the head on or off.

Larry - There are two crank seals on each side. I have both springs facing out which seems to be how the manual I'm reading says to do it although it is somewhat vaguely worded so it sounds like that is incorrect.

For the hell of it I hooked up the compression gauge to see what it read. It maxed out at about 15-20 PSI. This is the first time I've worked on a two-stroke so I don't even know if a regular compression test means anything on a two-stroke.

I do have the the inner crank seals backwards. I called Hugh's Bultaco and he said I should be getting more compression even if the seals were in wrong. I'll go in and fix that.

Just took the top end off. Piston and rings are sealing well. I'm at a loss for the moment.

Just found a hairline crack on the cylinder sleeve by one of the flanges. While problematic I'm probably going to try a few things as is. I'm not ready to put more money into this bike as it sits now.

I'm going to try to lap the head and cylinder mating surfaces together to make sure they are a nice seal. I'm also going to try some sealant along with the base gasket just to see what happens. Before that I'll probably try a pressure test. I found Saw Miller's pressure setup and I'll try that.

I'm going to step away and work on something, anything, else for a bit.

Chris, PM sent.

Thanks, Larry. I'll get back to you in a bit.

A little progress happening.

I lapped the head and cylinder mating surfaces together. I also tried a very thin film of ultra black sealant on the cylinder base gasket. Compression is still bad but it's up to 45psi, triple what it was before.

In the next few days I'm going to try a pressure test even though I think it's seeping air at the cylinder base gasket. I'm not sure how to rectify that yet.

I also readjusted the clutch with some direction from Larry. That helped once I started to get a little more compression and the clutch plates seemed to be slipping a bit.

Hi , I have noticed the cylinder head has a compression release between the 2 spark plugs , if this is faulty it will allow air to pass , take it out and replace with standard plug , make sure it has piston clearance though..

Hi , I have noticed the cylinder head has a compression release between the 2 spark plugs , if this is faulty it will allow air to pass , take it out and replace with standard plug , make sure it has piston clearance though..

I'm almost certain that's not where the air leak is but it's certainly worth a try.