Jetting specs for 06 crf250r with WB Aluminum Pro single system

Hey, I installed a full Wb aluminum pro exhaust on my 06 250f last summer, however i never really played with the jetting to get it right!! anyways, just wondering what a good baseline would be for jetting @ <1000ft, @ average temp of 15C. Wb included a 160 Main jet with the kit, and said to keep the needle in the stock 3rd clip postition. However this main jet seems like it would be lean, as it would be dropped from the stock 172 that came in the bike.

The bike seems to run fairly strong, however it stumbles when you whack the throttle open quickly from dead idle, in gear and moving, without the clutch. Not sure if this is normal, can be fixed, or if it has more to do with the AP than the jetting! I'd at least like to get my jetting fairly close to where it should be before i go any further playing with the AP settings. I seem to have no delay in the squirt, and it doesn't hit the slide on the way up, but it only seems to last for a 1-2seconds. also, the squirt only goes as far as just inside the head past the boot, and then just flows into the right intake port. Any help would be greatly apreciated, and btw, it's a canadian model, with a different designation on the carb if that makes any difference to you.

Stock settings include a 172 main jet, a 40 pilot, not sure what my pilot screw is set at right now, i have to check that this afternoon. and the needle in the third position. And the only Mod to the bike would be the exhaust.

Also, the exhaust came with the biggest end cap available with the pipe, that being a 49mm, however there's options there for a 45, and a 38 mm outlet, jst wondering what my best option might be in terms of these, as the 49mm seems way to big, because it's probably 40 percent bigger than the stock outlet on an 07 crf450r

the big out let is fine.its just loud.

you need to do the o-ring mod.

there is a pinned post at the top of the forum that shows it.

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