82 250 CR OUT OF IDEAS??

Have you reset your float height?
Is the needle for the float sealing off completely?

Paw Paw

If you passed a leakdown test with the piston below top of transfer ports to allow pressure to fill the crank well to test your crank seals if your piston and ring do not leak, you should not have a seal issue on either end of the crank

Here is the jetting I use on my 83 250XC. 38mm carb, 32;1 fuel mix, 330 main, 35 pilot, Q-5 needle jet, 6DH20 needle #2 clip position, 2.0 slide. This is at a corrected altitude of 3758ft. At a corrected altitude of 1340ft I run a 360 main jet and make an adjustment on the idle mixture screw slightly richer. Motor runs crisp and clean all through the RPM range and spark plug stays a nice tan color on the porcelain and light black soot on the outer edges of the base. Not saying this is the jetting you need but just to give you an idea. OH yea, have you pressure tested your carbs float valve?

Marty

yes i agree. i put the air in and gauge on the intake side so piston location should'nt matter. going to change them anyway have them on hand and motor is already stripped down. going to replace the float needle valve and seat when i get it back together recheck float height and start the jetting process.

i'm at around 1300ft do you know what stock jetting was? must be pretty close to my 82cr.

38mm carb, 32;1 fuel mix, 330 main, 35 pilot, Q-5 needle jet, 6DH20 needle #2 clip position, 2.0 slide
this for the 83 xc
your jetting:
410 main
R4 needle jet
45 idling
6dh20 needle
stock clip is 4th down i think i was at 3rd

I can see blubbering and smoking written all over this.....

I have a 87 Wr 400 here [ not mine ]that sounds rich [ blubbery but no extra smoke ] at full throttle and nothing I have done has changed it.
Swapped standard ignitions/carbs. [ ignition and carb off one that runs fine ]
Ran with no air filter.
Cleaned out exhaust.
Nothing changes it.
Funny thing is that the guy that sold it went thru the same process.
One day I'll get back to it if I don't die first.