More XR600 jetting questions!

98' XR600 - Have just installed an FMF Powercore 4 pipe, removed snorkel and ground header welds and as the beast still had stock jetting I started with a 155/68 setup and the bike was wicked, heaps of power but didn't respond quickly when I let off the throttle, also as it ran best with the fuel screw all the way in (I only ran it like this for about 5 mins) I figured it was too lean.

I then tried the same mj with a 65 pilot and it didn't run nearly as good and coughed and farted a fair bit more. I carried out both the adjustments correctly I believe so my question is, should I try the 68pj again with a 158mj or somethin similar. Jetting is not my specialty and I just want to get it right.

Any suggestions PLEASE??

My XR600s ran best with a 160-162 main and a 62-65 pilot. Elevation here is 500-800 ft.

I think '98's come with a restricted intake manifold. No?

You will need at least a 158, if not the 160/162 that Creeky recommended. I don't have an aggressive exhaust and I run 158/68 at lower altitudes.

You cant jet the lack of response out unfort. The stock XR600 carb is a pos.

Fit an FCRMX for respondo power

Thanks for the advice, I'll pick up a 158 & 160 and see how we go from there.

See my signature for specs-Currently running 158 main, and 68S pilot with full Big Gun Evo exhaust. The bike runs very well. The only thing I have yet to try is stepping up to a 160 MJ. Currently the 158 is fine, but until I try the 160, I don't know if it is the BEST or not.

Kawabuggy also which clip position are you running on the needle?

The 3rd I believe. Whatever it is stock, that is the setting it is still at. I have not tried changing the clip position yet but might be willing to give it a shot if there is additional power hiding there.

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