1983 250XC - jetting

Can anyone give me some ideas on jetting for a 250xc...having problems with getting the main jet correct...bike seems to bog on the top end...running 440 per the factory set up...changed to 400 with same results...any ideas ?? Thanks in advance for the info.

I have an 83 250XC that runs great and has good plug color.
This is in California high desert approx 3500 ft elevation.
I'll open up my carb tomorrow and let you know what I have (can't remember).

Lots of factors in jetting but if its just a main jet problem, check your needle for wear. Clip position?

1982 250xc jetting

Needle is 3rd postion from the top...and the needle is new...husky manual says 440 on the main...that is not even close on my bike.

Your first post says 1983 250XC, and your second post says 1982 250XC. FYI: Stock main jet for a 1982 is 410. Glad you found a new 6DH20 needle as Mikuni discontinued them long ago and can be hard to find sometimes. Try moving the clip one step at a time to the top position on the needle (lean) and try the 400 main jet again and see if that helps. If not keep going down in size. I have both the 83 XC and CR 250's, run great, all stock carb settings except for 430 main jets.

Don't forget to make sure your Air jet and passage ways are clear as it works in the 3/4 to WOT range.

Sorry this took so long, I forgot I had said I would do this for you.
I opened the carb and found the following:
Needle: 6F16
Needle jet: P8
Pilot: 30
Main Jet: 430
As I said, runs good with good plug color at 3500 ft
Ron

I got a 84 250 xc, im way up at 10,000 feet! Leadville, main 260, piolet 33. Runs great way up here!needle in the middle .air screw 3 turns out

"seems to bog on the top end."

Can you describe it more? If you hold it wide open, does the motor get a bit stronger as you roll OFF the throttle slightly? If so, the main jet is lean. This is described in the Mikuni manual. Always works for me.

Best way for main jet, IMO, is to go out and do a full throttle run, then chop the throttle and pull the plug and take a look. I run a 450 in my 83 250 WR. Smaller than that causes the above.