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drtbk4ever

Jetting feedback

4 posts in this topic

Hi gang, I have been doing a lot of reading on jetting and I think I have the hang of it, I just need confirmation that I am on the right track.

I have an 04wr450, Canadian model, so already has yz throttle stop and no grey wire to worry about. No other mods and stock pipe (I know I know, toss the insert. but I need it quiet).

Here is what it has.

main - 160

Needle - OBDUQ - 4th position

Pilot - 48

Leak - 50

I ride at 2000 feet in temperatures between 60 and 85

The bike outright rips when I crack it wide open so no issue there. But it still pops on deceleration so that means it is lean, correct? Indy's jetting specs suggest between a 165 and a 168 main for my elevation (but I am running stock exhaust ) so I thought I would go up to a 165.

I have no clue what to do with the needle as Indy is using the JD kit, but am I close with the OBDUQ on 4th position?

Pilot is a 48 already so I won't change that. But while cruising on low throttle (1/8 to 1/4) the bike has a major hesitation, sometimes enough to jerk you around a bit. Could that mean my Pilot jet is clogged?

Lastly, the leak jet. I think I am between a 40 and a 50 according to Indy's specs. Would dropping it down to a 40 give me a little more torque off the bottom?

Thanks for the input guys, I can't tell you how much I have learned from reading your posts.

Cheers

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I'm no jetting expert......but it sounds like your on the right track...I would start with a 40 leak, that little jet made a BIG difference, it cleaned up the lower throttle alot. If that doesn't help, play around with the pilot, if popping on decel(too Lean!!) move a size or 2 richer on the pilot. Lastly, If you can get the JD needle, its tapered for a great running bike.

Good Luck!

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Decelleration popping can be rich or lean jetting.

Does you bike smell like unburnt fuel?

Does it get harder to start when hot?

Your PJ might be a tad rich. Try leaner, maybe 45.

And always remember, Only change ONE thing at a time.

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Hey Guys thanks for the info.

Good point about only changing one thing at a time.

MotoGoalie, the exhaust has never smelled like unburnt fuel and the bike starts easily when hot. I have never needed the hot start lever. All I need to do is press the starter and give the throttle the tinyest twist.

So is popping on decel usually a pilot issue or a main issue?

Cheers.

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