Tuning Gorr's 265cc kit

[WFO]

I'm trying to tune the new 265cc '97 YZ I just got back from Eric. Stock settings are #48 pilot (air screw 1.75 out), jet needle in the 3rd clip with a 170 main.
The previous owner had installed a Boyenson reed and a 168 main.

Bear with me on this....

I've read that these reeds tend to require a leaner main (hence the 168). In theory, the slightly larger bore with the old carb should also require slightly leaner settings.

The bike doesn't start very easily, but idles fine once it's warm. It pulls off well, but "hesitates" around 1/8 to 1/4 throttle. Past 1/4 and it pulls like a tractor. By "hesitates" I mean it gets ragged like it's loading up.
I've raised the clip (IE-leaner) to the 2nd and finally the first position. Each change helped noticably.
Trouble is, the hesitation, while better, is still there. I've tried the air screw everywhere from 1.5 to 2.5 turns, with the best results at the original 1.75. Frankly, other than a slight backfire at 2.5, I really couldn't tell much difference with any of the screw settings.

From my remedial Carb 101 course, I'm thinking the 1/8 to 1/4 positions are primarily effected by the jet needle and slide cutout, and to a lesser extent, the pilot. Since I'm at the top clip, do I need to get a leaner needle? A leaner pilot? Different slide cutout?

What's my next step?

 

[jmics19067]

.

If the bike is easier to start when cold instead of hot the pilot sounds too rich
If the bike start easier hot instead of cold the pilot is possibly too lean. This is of course if your choke circuit is working properly and your reeds are in good shape. Don't forget your float hieght and needle and seat.
Pilot jets are pretty cheap as is needles compared to slides. they all overlap each other a little bit. I think I would try the cheaper options first and get it to start easy as a baseline for the pilot and then fine tune the air screw. less than one screw out go richer on the pilot more than 2 full turns one leaner on the pilot is usually right.

If you are running the needle clip in the top I would suggest you get the next leaner needle. If the bike is running clean from around 1/2 throttle on up but still blubberry around 1/4 then I would try a leaner slide.

 

[whyz]

Clean carb. Start over. Back to stock.
Very important >> (Float height).

The backfire thing? Me Too. Sometimes it seems it wants to.
I dont know. I'd like to know though. :silly:

Good Luck.
I'd like to know what you came up with.
Thanks.

 

['00kx250spode]

I had a hesitation at around 1/8 - 1/4 throttle while jetting my EG KX310. I couldn't get rid of it with a leaner pilot or needle clip position. I fixed it by going with a needle that had a thicker straight section.

 

[WFO]

Which leads to another question. Everywhere I've looked, I can find pilot and main jets, but no jet needles. What's a good source?