Richer main jet killed my "hit"

3 replies to this topic
  • Steve_Morgan

Posted May 08, 2000 - 11:17 AM


Since I've heard that the stock jetting is too lean with the baffles removed, I swapped my 168 MJ out for a 172, opened the air screw from 1 1/2 to 2 1/2 (45 PJ), and put on a White Bros. air filter. Now the bottom end is stronger, but the transition to midrange is very smooth. With the prior overly-lean stock MJ, I had a very cool & fun "YZ hit" in the midrange. I'd like to keep the WR timing stock, I like the engine braking on single-tracks, and fuel economy for those long desert rides. Can I get the "hit" back with a needle change? WR timing, 45 PJ (2 1/2 turns out), 172 MJ, no baffles, cut throttle stop, 1-3K feet.

  • mcarp

Posted May 08, 2000 - 12:26 PM


I have the same setup, except airbox lid on.

I use the same jetting, except i moved the needle clip to #4 from #3. For me, this cleaned up the jetting and gave better low-mid. More importantly it cleaned up the hesitation snafu.

However I run at 600 feet, and my fuel screw is not out as far as yours' is. Every bike is different, so experiment.

I would try #4 clip position first before buying anything more. The "hit" your talk about is definately there, but it is smooth.

PS When Clark talkes, people listen

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  • Steve_Morgan

Posted May 09, 2000 - 11:20 AM


Thanks for your input, I'll give the #3 position a try with my stock needle (DTM?). Clark, do you have any suggestions for the best "hit" with WR timing?

  • Kyle

Posted June 05, 2000 - 12:16 PM


Mcarp, the hesitation you are talking about, is that from idle to giving it a quick twist?

I just tried Mike Trains idea on removing the baffle and using the auto exhaust trick until I save up enough for the Big Gun. Went to 142, 45 and 1-3/4 turns out. And if you remember I live fairly close to you. How many turns out is your air screw.
Anyways, I have that prob with the hesitation (idle-quick twist) do you think I should try moving the clip to the #4 position?


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