Main Jet wear??

Have you ever noticed that a main jet that has been in the bike for quite some time will begin to wear on the threaded side. The motion of the needle going in and out of the brass jet will deform the pefectly round hole and make it slightly larger and egg shaped.

I noticed this while making some jetting changes today, and I compared a few jets that I have run for a while with ones that I haven't.

My question is, does the deformity of the hole on that side of the jet affect the jetting to a measurable degree as it wears. It would seem that as the hole wore bigger, it would let the main jet begin to come on a little sooner. Does that sound right?

Sounds logical Wyatt, Tell me your specs now. I just installed a ejp needle and have just put in a 40 pilot to test your settings. My neighbor wouldnt like it if I test ride it tonight though! But it starts fine!


My bike was a monster at about 45° with these settings:

38 pilot

stock needle / stock position

168 main

This past weekend as the temps got warmer, I began to have to use the hot start. I never did in the past when the air was colder. This tells me that I am getting a little richer due to the increase temps. It was also not quite as crisp as it was in colder weather. I just changed to these settings:

38 pilot

EJQ needle / 3rd clip

165 main

I have not had a chance to ride it yet. I hope to be in the ball park of how my bike ran at the lower temps. I really had it dialed during the Winter months. I may be able to test it a little tommorow. I can't get too crazy on it because I don't have a back brake pedal yet. I have mine removed because I destroyed it in a crash last weekend.

I was also very bummed to find that I put a nice dent in my TA pipe in the expansion chamber section before the muffler. I am not sure how that will affect the pipe's performance......can't help any. I am still pissed.

You changed the needle to a EJQ? EJP was stock on the 2001 wasnt it.

Yes, I believe it was. The Q is one step leaner.

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