KDXRIDER.NET

I was wondering what jets I should use for my 91 kdx250. It is stock (to my knowledge) and it seems like it is jetted pretty rich. If I jet a little leaner it should run a little snappier and foul plugs less often right? I won't be racing the bike at all, just trail riding. Also, what plug should I run and what is the proper gap? Any help is appreciated. Thanks

A KDX should never foul a plug! Seriously... I forget to change mine from year to year.... Usually a BR8ES is what most bikes run. gapped at about .035" or .8-.9mm if I remember correctly....


It would be best if you told us what is in your bike now so we can tell you how bad it is.... you know... for conversation purposes...

Thanks for the info. I am running an NGK plug right now. I am going to get a new plug because I'm not sure how old this one is. I wasn't sure about fouling, I've just heard other people say that a rich mixture will foul plugs if you don't keep the engine revved. Like I said before, I am new to the 2-Stroke world. I've been riding for a while, but this is the first 2-Stroke I've owned so I have to get used to a few new things. I've also heard that the KDX250 was jetted rich in stock form. Mine does seem a little rich. Should I re-jet or just not worry about it?

Don't know.... Depends.... if it is fouling plugs then I would say yes. If it is running like a dog, I would say yes. It would be helpful to know what jetting you have in there now though.... need a baseline to go from. There are guys around the same elevation as you with KDX250's that can give you some recommendations. radonc73 would be the guy to ask...

You needs a NGK BR8ES spark plug... you can get them at Farm and Fleet or Rual King if you have one close by. They are cheaper there....

Learn how to jet a bike, and you will be a whole lot better off than just doing what someone tells you to do. For starters, long-distance jetting doesn't work. How you ride your bike, the type of riding you do (those two aren't the same...right?), the fuel you use..it all matters.

Do some research, for a start.

This:

http://en.allexperts.com/q/Motorcycle-R ... etting.htm

...which has some info from Eric Gore about basic carb types and jetting.


Pay attention to someone that knows what they're talking about (if you can tell)...not what 'someone saidl'.

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In keeping with the above...please do take note that I know how to spell the guy's name. Try it in google, and you will find that many people are so interested in what the guy has to say...they don't even know what the hell his name is.



Most bikes are jetted rich from the factory. They don't know what you're going to do with it. Ride in the sand at sea level? Ride in Colorada over 10,000'?

Should you rejet? Absolutely. If for no other reason than getting acquainted with your bike and how it runs on either side of 'correct'. Besides, in most environs, you will need to change your jetting with the seasons.

A manual would be a good place for you to start. Not only will it tell you what the gap on your plug should be (the 200 spec says .7-.8mm). What is that in thousandth's of an inch?

Having absolutely no idea what's in the bike now (please do find that out, as Inda has suggested...twice), you need to find out. It's a good way to introduce yourself to your carburetor!



And it's GORR 'fer crine out loud.

nearma - Another member - "Rick" - has a KDX250 and resolved jetting issues by getting a leaner slide. Before the leaner slide, we had his pilot jet down to a 35 (smallest 21-series pilot) and the pilot circuit essentially just didn't do anything for him. Had the idle adjust all the way in (up).

Going with a leaner slide made a WORLD of difference in having a pilot circuit that was actually tuneable and throttle response that was much improved. Rick will have better details.

You can get a new slide or send it off the Ron Black and he can cut it for you . . .

and while you're at it consider having him install one of his dandy divider plates. I think you'd be the first one on the site that did so on the KDX250.

Yeah... I think Ron can cut yours cheaper than buying a new slide....

http://www.rb-designs.com/slide-mod.htm

Yes, $15 vs $70ish