94' KDX250 Mods & Performance Tips

[antonyp]

I recently bought a 94' KDX250 and I plain love it. But I would like to improve the bike's performance especially on the low-to mid power curve. :aj: I don't need the top end part much cause I am using the bike mainly for country crossing which is mostly tight dirt roads between fields, hills and woods. Any help anyone? Can anyone tell me a little more on those Eric Gorr's cylinder kits I hear about in these forums? :think:

Antony

 

[KiDX]

If you haven't done it already, lose the stock exhaust. ;)

 

[Matt90GT]

1. Get a pipe and silencer
2. remove the air snorkle on top of the airbox
3. get some good reeds, like the FMF torque reeds for low end
4. Rejet the carb if you need to: 42 Pilot, 165 main, 2 clip from top on the needle
5. New air filter (same reason you need new reeds, they are probably old)
6. Install a KX .26" thick head gasket. Your stock one is .46" thick.
7. Porting, boring, etc

But you may want to check my page on my 91 KDX250 as I found a lot of where the parts come off of other kawasaki models. It helps finding parts:


http://mlbobbitt.home.attbi.com/kdx250/1991kdx250.html

 

[antonyp]

Originally posted by Matt90GT

3. get some good reeds, like the FMF torque reeds for low end
4. Rejet the carb if you need to: 42 Pilot, 165 main, 2 clip from top on the needle

Hey Matt! You better take it easy on me! I don't know much about these things just yet!
What exactly does rejet the carb mean? and how do you do it? I know about the needle, ok that's easy to do, but I don't have a clue what you mean when you say: 42 Pilot, 165 main. Are you referring to the compression ratio? Pls explain...
By the way I've seen your bike at the url you posted. Awsome-looking bike man! It really rocks especially with those twin headlights!
Also, about the reeds! I know what the reed valves are, is it the same thing? No? :silly:

Also does anyone know any of those performance sites that will ship outside the us?

 

[Bruce]

Sweet bike Matt. Looked at your site. appears to be a Moose fender bag or similar; just put one on, holds plenty. I also see you've gone to a BR7ES, which I finally had to switch to on the weekend, as this year the bike has been loading miserably on a BR8 (yes, I changed the filter, also running a UNI).

Pipe and silencer are a good first step. I didn't remove the snorkel but drilled a few half inch holes in the top.

Matt, have you ever ground down the steering stops... I think I'll have to, tired of getting stuck in deep woods turnaround situations where I have to work it back and forth (sometimes do the wheelie and spin turn, but by end of day getting too tired to do that).

 

[dirt bike dave]

Bruce - on mine, I did grind down the steering stop on the frame. and repainted. It will certainly steer tighter after this is done.

The forks are not very good stock. After some fine tuning to the engine and chassis, the bike can be vastly improved over stock and lots of fun.

 

[Matt90GT]

Thanks for the compliments!

I have thought about doing the same thing with reguards to grinding down the frame steering stops. Seems like there is about 3-5* per side turning you can gain without hitting anything. That maybe my project this week before riding, along with setting up the preload in the rear and fork height up front.

I did forget to mention to run a hotter plug. #8, switch to a BR7es plug.

antonyp -- if you have been in the carb for the slide, then you can reject. Basically remove the carb from the bike. It is easiest to do this the first time you mess with the jets so you can see what is in there. Take the bowl off. There are 2 round jets there. The smaller one is inside a tube, that is the pilot. Remove the jet, they are marked with a number. Then the main is the one you can remove with a 6mm socket or wrench that sits down inside the bowl there. Again, there should be a number stamped on it also. Check where you are compared to the recommendatioins. I got the number off the FMF site and they seem to be the same as stock with the needle one notch higher. So good chances you are okay in the jetting. If you have a stock pipe, maybe drop one size on the main to lean things out.

For the suspension, I have not been out riding yet. So I cannot tell you any tips there. Maybe after the weekend. But I did install new fork seals and filled up the fork with some amsoil 10w fork oil. I have 5w in the garage, but figured I should start at what I have always used for a baseline and adjust from there. I do have the compression clickers all the way then 4 turns in if I remember correctly.

Last thing, reeds. Where the carb connects to the cylinder head, you can remove that piece from the cylinder head with like 6 or 8 bolts there. That is the reed block. Real easy to get at while the carb is off. Most likely it is time to replace them.

http://www.fmfracing.com

Got there, click on 2 stroke at the top, then reeds on the left side. Scroll down to the torque reeds. They are white and blue. I installed a set of those with the other mods on the bike and the power is so mellow. You can hear the hit but not really feel it on the street. Feels very tractable for the woods.

 

[antonyp]

Ok Matt! Now I get what you mean by "rejetting" the carb. You see I already opened up the carb put it apart into pieces and cleaned it a couple of weeks ago so know I know what the jets you were referring to are :D
I am gonna check those numbers and act accordingly. But my biggest problem of all in which I would really appreciate greatly any help I can get is to find out if there is anyone or any site that would ship parts outside the U.S so I can get them. :ugg:
I 've been into the FMF page and saw the reeds you told me about, thanks again, but I couldn't see any for my model of KDX. Which ones whould I get for my bike (KDX250-1994)? :eek:

 

[Matt90GT]

http://www.denniskirk.com/powervendor/details/detail.asp?serverid=OffRoad&PartNo=18424

 

[antonyp]

Thanks Matt! Now I know which reeds can go on my bike! Do you also know which FMF fatty pipe I can use? I think that suits my needs perfectly...
And where will I find jets for my carb just in case I need 'em?
'Tis quite a hussle to set-up a bike the way you want it when you live in a small Island like mine! You can't even get stock parts for most models. I wonder why they bother selling 'em? :|

 

[Matt90GT]

Look on the FMF site for the pipes available.

92-93 KX250/91-94 KDX250 is what is it listed as.

For pipes and jets you can get them from Dennis kirk.

 

[Oregon Trail]

Matt90GT & antonyp,
I found that the 5w fork oil works the best in the KDX250. I had 10w and hated it, too harsh. There's been some good advice on setting up the suspension of the 250 in other threads. I felt the best inprovements on the KDX250 are new exhaust, re-jet, snorkel/drill airbox and rework the suspension. Once you get the suspension dialed in, then do the engine mods; reeds, head gasket, porting, etc, unless something is bad already. :D

 

[Matt90GT]

Thanks for the info! I am really debating swapping out to 5w oil. I just put in new fork seals and 10w but have not been riding. Everything that I read says 5w oil also. Guess I may do that before riding. Thanks for chiming in!

 

[antonyp]

Yeah, thanks Oregon Trail. I have to agree that properly set-up suspension could be the most important factor in riding well in those narrow mountain trails and woods...
Matt, I 've sent an e-mal to Jeff at MXSouth and he said he can ship things to me in Cyprus so I am ordering some of the stuff you told me to get soon! The head gasket you told me to get (KX .26"), is it the one for the 92-93 KX250 like the reeds? Or a different model?
Also, the BR7es plug you mentioned, is it NGK?

 

[antonyp]

Oh.. one more thing! Which silencer/spark arrester should I get to complement the FMF Fatty exhaust system?

 

[Bruce]

It would be NGK.
When I bought mine it had (and still has) the FMF pipe and ProCircuit silencer. It works well.

 

[dirt bike dave]

antony -order the head gasket from an '88 KX250. Some years of KX offer both thick and thin gaskets, but the '88 part number is for the thin one.

 

[antonyp]

Thanks for all your help guys...
I am soon going to start the mods on my bike! I just can't wait to make it really meaner! :debil: