Husqvarna wr 250 keihin pj jetting, where to start!?

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Oct 14, 2012
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#1
Hi all

I have just put a keihin pj carb on my husky wr 250 but I don't know what jetting to start with. I changed the carb due to some nightmare jetting issues with the mikuni tm carb so I'm hoping I can get this one dialed in! :-/

Does anyone have any idea what jets I should start with? At the minute I have a 170 main & a 62 pilot, I have a spare 40 pilot that I could try but I think this may be too lean.

Would the jetting on this carb be similar to a keihin pwk from the same bike?

Iv had the bike a couple of months now & it flies above 1/4 throttle but I just could not get rid of a stutter at 1/4 throttle! :-(

Any help is greatly appreciated.

Adi
 
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#2
I cannot help you much with the jets numbers thing, but, some bikes do allways "stutter" on the small throttle openings. it´s just the way they work.
sometimes reeds (like the boyesen, or stock but new) had cured long time jetting issues on the small end. advancing the ignition timing when possible help somewhat as well... high performance exhaust tend to increase the dificulty on low end jetting.

usually that kind of stutter may come from rich or leaner mixtures but most of the time its rich mixture. doesn´t hurt to try the 40 slow jet... try to move the needle up as well to see if it helps. at quarter throttle i find the most dificult to attain smooth running since the low speed, the needle and the cutway overlap a lot.
 
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#3
Hi

Thanks for the reply, someone did say to me that this is just the way these sort of bikes run but I just feel that it's too rough to keep it lie this. If I was just off road I would not care but as I have this bike on & off road the problem area of throttle is where I spend 95% of my on road riding. As it is, it's impossible to cruise along at a steady pace without it stuttering all the way down the road! It's only when I open it past 1/4 throttle that it runs smooth.

Are you saying this kind of running may be unavoidable or should I be able to get it right with jetting or at least somewhere close? I just fear that I may be doing damage to the engine by riding it like this all the time & also it doesent sound or feel good when riding along at a steady pace.
 

Farmer John

T.C.F.<br>(tire changin' fool)
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#4
adic3001 said:
Would the jetting on this carb be similar to a keihin pwk from the same bike?
It will be pretty close.
I would try the 40 pilot jet.

What needle do you have?
 
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#5
I'm not sure which needle I have as I wanted to play with jetting first, il check on Saturday & post back which needle I have.

Do you have any suggestions of what needle could work best as I have no idea?

Thanks for the reply, much appreciated
 
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