Pilot jet question

I think I know the answer but wanted to pick some brains.

My bike runs and starts good. It surges just off closed throttle to 1/4 throttle. The fuel screw is at 2.5 turns and the pilot is a 45. I think I need to move to a 48. I played with the needle clip but no change.

My current jetting is:

45 pilot

Stock needle on clip position 5

165 main

Turn your fuel screw out a couple more turns and see if the response is better. If so, then you need a bigger pilot jet.

Turn your fuel screw out a couple more turns and see if the response is better. If so, then you need a bigger pilot jet.

Do not turn fuel screw a couple more turns out.

48 pilot

Clip in #4

Main 165

Do not turn fuel screw a couple more turns out.

48 pilot

Clip in #4

Main 165

+1 on that.

Maybe 2 1/2 out from full in at most on the fuel screw. The needle should be at #4.

Mine runs fine with the stock 45 pilot. Fix the needle and it should run good with what you've got.

Do not turn fuel screw a couple more turns out.

48 pilot

Clip in #4

Main 165

Care to explain how turning a fuel screw out a few turns for testing purposes should not be done? I never told anybody to ride it like that...

w.t.f, I take a 8 month break from this site... log back on and 2 hours later I remember the exact reasons I left.

First, adjust the pilot according to the manual so that the idle itself is correctly adjusted. If the pilot screw needs to be backed out more than 2 to 2 1/4 turns, the pilot is too small. Most likely, the 45 will be OK.

If the surge is still present with the pilot correctly baselined, try the fuel screw out farther to see whether that will correct it. If it does, it's a fault with the needle. Next, return the pilot to its correct setting (presumably, the surge will return), and see if the bike runs correctly in the range from 1/4-3/4 throttle. Since you have already raised the needle beyond the #4 position without resolving the problem, I suspect that it's going to require another needle.

The surge you describe, being between about 1/8 and 1/4 throttle is not uncommon in the '08 model, and is usually best fixed by changing the stock NFLR needle to an NFLP (5TA-14916-LP), or possibly an NFPP (5TA-14916-PP). These needles each have the same taper as the stock needle. The NFLP has it at the exact same height as the stock NFLR, but the straight section of the needle is smaller, making the engine one step richer between off-idle to the point where the taper starts pulling up out of the needle jet at about 1/4 throttle. The NFPP is the same except that the taper is higher (therefore richer) by one half clip position. With either needle, start in the #3 spot.

By approaching it this way, you'll have a good clean idle, reduced stalling, get rid of your surge, and probably improve the response coming off idle.

I have a 48 and a NFLP. I'll try one, then the other, then both.

Easy enough. I might take a trip out after work just for jetting.

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