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-   -   Rejet a stock bike? (https://www.kawasakiforums.com/forum/klx-250s-71/rejet-stock-bike-38179/)

mikesova 06-05-2012 02:02 PM

Rejet a stock bike?
 
I've searched. Pretty much all the threads I come across involve rejetting for a modification, exhaust, intake, etc. I'm perfectly happy with the current HP of the bike, but I know that these and most bikes are jetted lean from the factory. In a normal stock from the factory situation, what would the best jetting situation be? I'm in Michigan, btw, so I'm not at 10,000 feet or anything.

ahnh666 06-05-2012 03:19 PM

the dyno jet and moose racing (also, a dyno jet) comes with various jet sizes...i'm sure you can use the small jet sizes on a stock bike...i think that is considered "stage 1" in the instructions....if you don't plan on modding and moving up to the bigger jet sizes, i'm sure people have lot of the smaller main jets lying around...i have all the main jets below dj132 in the dj kit...that is if you just want to just increase the jet size a little bit...and keep the fuel needle and spring stock...

IDRIDR 06-05-2012 04:05 PM

Best jetting for a completely stock bike is probably the jetting it came with. Lean and mean are fine. Overly lean burns things up and that doesn't happen often or Ma Kaw would be taking a lot of bikes back.

That said, the stock needle can be improved on with a dynojet needle, or some use N1TC. But if you're not modding anything else (air box or exhaust) and you're happy with the power, why mess with it?

mikesova 06-05-2012 04:10 PM

yep, not interested in aftermarket parts, just want to keep it stock.

jhoffy22 06-05-2012 04:20 PM


Originally Posted by IDRIDR (Post 475103)
Best jetting for a completely stock bike is probably the jetting it came with. Lean and mean are fine. Overly lean burns things up and that doesn't happen often or Ma Kaw would be taking a lot of bikes back.

That said, the stock needle can be improved on with a dynojet needle, or some use N1TC. But if you're not modding anything else (air box or exhaust) and you're happy with the power, why mess with it?

Speaking of jetting, did you change yours from the 128DJ after you got your 351 installed?

I think I'm running 38 pilot (Kawi) and 132DJ right now. I need to take it apart and have a look.

ITHAPPENS 06-05-2012 04:28 PM

Just did my stock 2011 with Dinojet stage 1, needle and main jet, airscrew drilled and 3 turns out. Great improvement over stock. Nothing radical, just revs much quicker and slightly more power everywhere. Elevation about the same as you mikesova... Best $50.00 and one hour install spent so far.

IDRIDR 06-05-2012 04:36 PM


Originally Posted by jhoffy22 (Post 475106)
Speaking of jetting, did you change yours from the 128DJ after you got your 351 installed?

I think I'm running 38 pilot (Kawi) and 132DJ right now. I need to take it apart and have a look.

Not yet. Plan to drop pilot back down to 35 and try a 124 DJ main.

jhoffy22 06-05-2012 04:44 PM


Originally Posted by IDRIDR (Post 475111)
Not yet. Plan to drop pilot back down to 35 and try a 124 DJ main.

You don't think that will lean it out too much? I see that your mean altitude for Idaho is 5,000 feet above sea level. I'm at ~1,000 feet above sea level.

i really do need to mess with the jetting though. I feel as if it kind of sounds like it is sucking air when I am in the higher gears.

DYNOBOB 06-05-2012 05:41 PM


Originally Posted by IDRIDR (Post 475103)
Best jetting for a completely stock bike is probably the jetting it came with. Lean and mean are fine. Overly lean burns things up and that doesn't happen often or Ma Kaw would be taking a lot of bikes back.


I agree. Leanness is more evident at idle than cruise and WOT. If you feel the need to slightly tweak this is what I did (fully reversible).
1. Turn the idle mixture screw out 2.75 to make easier to start.
2. Add a washer under the stock needle to richen a little at cruise.
3. Maybe go to a Kehin 120 main. See my dyno thread. It was debatable and I may put the 118 back in.


.

IDRIDR 06-05-2012 07:41 PM


Originally Posted by jhoffy22 (Post 475114)
You don't think that will lean it out too much? I see that your mean altitude for Idaho is 5,000 feet above sea level. I'm at ~1,000 feet above sea level.

i really do need to mess with the jetting though. I feel as if it kind of sounds like it is sucking air when I am in the higher gears.

I'm at 2,500 ft here and generally ride up from here to 8 to 10,000 feet. Next weekend I'll drop down to 750 feet in Hells Canyon.

I'm pretty sure I can go back to 35 on the pilot. Others here mention doing so with 300, 331, & 351 jugs. I'm getting very little feedback from the Kouba screw until down to around 1 turn out and less. My tail pipe and rear fender is building up the black stuff. On the main jet, the plan is to spend some quality time on a lonely road with some WOT runs and a few different main jets and dial it in. Bill's advice was "two jet sizes up on the main." I was rich before the 351 kit with a 124DJ. A 128DJ is eight sizes up from stock! IMO, a lot of us here tend to overjet the main based on advice from others who have overjetted the main.


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