Congrats on getting it finished. :D I am sure you will have to do some carb tweaking and suspension clicker adjustments but I hope its close for you.

Thanks, I hope so too.

There is no powervalve leak of any consequence in 92-96 .CR 250 s

While the engine is running 1 psi drop in 6 minutes is nothing.The engine is running at 1000 s of rotations per minute.

Also the engine tolerances will tighten up once the bike gets up to temperature.

The main consideration is for the valve assembly to be free of stiction.
Rubber o-rings, seals-goop whatever=drag.

Thanks for the post and update! Btw, the bike runs good but it is a very rich on the bottom with the airscrew at 2.5 turns out, I am going to try a 48 pilot. Right now I have a 175 main,52 pilot, R1369N needle, boyesen rad valve and FMF Gnarley,FMF spark arrestor/silencer. Does this sound like I am in the right ballpark?

Original Startup
 

It took me a while to get caught up on some other things. Here is a video of the original start up after the build in September 2017. I have put about 20 hrs on her now without any problems. She is very SMOOTH and very FAST. She is probably the fastest 250 that I have ever rode. In straight line acceleration she is about as fast with a little less torque as my 2011 GasGas 300.


https://www.youtube.com/watch?v=j-pkG5liJ_8

Tried to watch the video. Broken link?

I will check the link.