KX-250 Woods Conversion

I converted a '98, '99 and '00 KX250 for woods use with good success. The most important thing you can do to make a successful conversion is to spend money on the suspension. ACME Suspension in Ca. did my suspension work and it was excellent- they used to do Ty Davis' and Brian Brown's suspension when they were on KX's. Do a search for KX250 jetting as these bikes were a little finicky with respect to carburetion. 13 oz. is a little heavy on the flywheel, you might try a 9 or 11oz. first. Of course this depends on your riding style and the conditions. If you are a gear high and want to get moving quickly, a fan of the clutch does not yield as quick a result w/ a heavy flywheel weight. I never made any timing mods so I can't comment on that. In '98 the motor was a little abrupt so E Line sold me a thicker base and head gasket, lowereing the compression and changing the port timing but the '00 motor is tame enough stock IMO. The '98 always seemed a little more steady and tracked better than the'99 and '00. If your handling is too quick you might try sliding your forks down in the clamps 5mm. I ran 2 teeth more on the rear sprocket; again that depends on your conditions. Other than that you are on track with guards, etc. BTW the Super Q will soften your power delivery on the bottom by virtue of it's length. Which may or may not be good depending on your conditions.
Mike

e-line has lots of goodies for your bike. www.elineaccessories.com

Factory Connection also does an excellent job with woods suspension on MX bikes.

IMO, a well setup Japanese MXer doesn't give away anyting to the pumpkin or Gas Gas enduro bikes.

dtsviper,
Sorry I missed this thread. What mods have you completed?

Ive got the same bike as you and have done hand gaurds and cut down the bars in length 1 inch off each end. Also I tried a 51 tooth rear sprocket but found it to be a little to much for my riding style,( a mix of mx and woods) so I now have a 50 and like it much better. Ive found
the the biggest problem to be my lack of skill, not the bike.

I had a 2000 KX250.. The reeds will not last long in the OEM reed cage, I went to a V-Force setup. It's an easy bolt-in and works excellent, it was still going strong a year later when I sold the bike.

The lower shock bearing needs constant attention, every time I'd pull it apart it would be rusted out/seized.

You may or may not want to go to a larger tank. I tried a 3.1 gallon IMS tank, I found it too bulgy, my knees would hit it and I found it difficult to get forward on the bike.

I had my forks pulled up as high as they would go through the clamps, I still didn't get any headshake, but cornering sure got better.

Next time you have the top end off, check the cylinder walls for any of the plating chipping off, and check the rod for excess side to side play. Mine had both at low hours.

MSR makes some cheap radiator guards that work well in conjunction with the OEM braces. You may want to add a vented front number plate to compensate for any loss of airflow due to the radiator guards. I did, and I never overheated it.

First gear is rather tall in stock form, watch the other thread for any wider ratio transmission options..

A good skid plate will save your frame from the beating that mine took.. The Works Connection glide plate did not cut the mustard.

The KX should prove to be a great woods weapon with a few mods. Good luck with it!

Originally posted by WaltCMoto
Ive found the the biggest problem to be my lack of skill, not the bike.

Click to expand...

Me too. :thumb:

Good stuff here. Cam is dead on with the lower shock bearing problem. I'll go one step further and say to keep all the linkage bearings well lubed as they tend to go dry in a hurry. I just tore my bike completely down for frame powder coating and the bearings were shot. I just lubed them good in the spring. While I have it torn down I'm going to install zerk fittings in the linkage to aid in keeping them lubed.

I have the Gnarly/Turbine Core II combo on my bike when I need a spark arrestor. Otherwise I run the stock silencer.... power delivery is better to me.

Like Walt I found the 13/50 gearing to suit me best, but I'd love a lower first gear and so not to give up any on top. 14/50 would be too high, but our trails may be tighter than what you have in Tejas.

I went with the 9 oz. FWW, it help my stalling problem in the tight stuff. I didn't want to go too heavy and loose the throttle response to get over logs, etc. Once my bike is back together I plan on removing it to see if my clutch work has improved.

I'm in the process of adding a new front brake line, routed Honda style. The '01 has much improved fronts brakes, but you need to bleed nearly every time you ride. :|

I've installed Works Connection Radiator braces and skid plate. The rad braces have saved my radiators many times, but one time in particular I went into the trees deep into 4th gear and had a nasty get off. I took one of the trees just outside the left fork, it pushed my bark buster (a must have) straight up, torqued up the left shroud and the plastic radiator grill, but the radiator was still straight. My Pro Tapers didn't bend at all either.

I haven't had a problem with my skid plate but it's mostly sand and clay here. Cam, you prolly have lots of rocks up there?

I revalved my forks with '00 KX 125 valving specs and it's much improved. I need a slightly lighter spring for the rear and that will be complete.

The two best mods so far aside from the suspension:
I had Eric Gorr hook me up with a 265 kit with Mo Better porting. :yeehaw:

Recently installed a GPR stabilizer, I'm sure your Scott's is just as good. OMG what a difference! To all the folks that said "once you ride with one, you'll never go back."
:thumb: :thumb:

Couple of other things to watch out for:

I had a DID O-Ring chain on mine for a while. It rubbed the case behind the countershaft sprocket to the point it removed a fair amount of metal. Be careful of the one you select as some are wider than others.

My airbox separated from the airboot and mucho dirt entered the carb. This lead to my 265 kit. Mixed blessing there, but I don't want to repeat it. I found the metal flange to be bent. I straightened the flange, resealed the boot/box junction and added a Proseal (highly recommend).

I'm with Cam on the tank deal, I’ve yet to see one that didn't add allot of bulk up there.

Keep us posted.

Clark makes a nice narrow fitting tank. My CRE250 was equipped with one and I didn't loose much, the best part was my seat stayed flat. I just purchased my '03 KX250 and will be taking it out tommrow for the first time, but not before I disassemble the bike a re-grease everything, add my headlight, tail light license plate holder, and 28in bars 'n hand guards from my CRE. I'll find out tommorow if I'll need lighter springs in the suspension (it will need a revalve, for sure). I prefer the WER steering dampner, and I will order a pair of Devol Radiator guards. I have both the Works Connection Rad guards and the Devols for my CRE. The Works Connection made it possible to use the stock plastic guards and offered better air flow. I prefered the Devol's, though the hindered air flow alittle. They really totally protected my radiators from looking more trashed then they are. They're very strong, and they wrap around the radiator for total protection. The only downside is you can't use the stock plastic louver guards which help deflect airflow on to the radiators. Thats ok, though, I always lose the plastic ones anyway. The CRE rarely overheated even in the longest of tight sections or muddiest of National enduros (Delaware '02). The Devol guards have my approval of best Rad guard, because they really do protect your radiatiors, without a doubt, when the '03 Kx's guards come out, my bike will be equipped with'em. I decided to change suspension tuners and have WER revalve my '03 KX for Eastern nasty. The clutch feel on the KX is already very good, but I'll be putting my PEP atv clutch perch and shorty lever from the CRE to the KX. Do not mess with the Magura unit!!! I had one on my CRE250 at the beginning of last race season and only got two and a half races on it before the seals blew. granted, I loved the smoothness of the juice unit, but riding half of a enduro with no clutch really sucks! Just do Motion Pro cables and replace three times or so a year. It worked for me and my clutch engagement was always smooth and reliable! I did purchase a Excel 18in rim for the sake of getting less flats. Works Connection already has good lookin' frame guards available for the '03. Clarks big fuel cell will be available early this spring, expect a nice compromise of fuel capacity and slim fit. Thats all I can think for now. Find out tommorow a little more about possible Eastern Set-up.

dtsviper, I have a 2000 that I bought with a 9 oz Flywheel weight that I'm going to remove if you want to make a deal. I ride 50/50 trails/mx, and coming off of a '97 KX 250, I really miss that fan-the-clutch burst. The bike still responds to the clutch, but slower. I would probably not tire as soon with the weight, but I just ride for fun, and don't have much corner speed, so I need that burst to help with jumps.

I have a 01' kx 250. I had my suspinsion done my Bruce Triplet. He put his Tarain Tamer system in it. His work is awsome. He gets is set really close, but you can adjust it with the clickers to the perfect settings.
I just added a 11oz flywheel weight. I love it. It still had the snap in the motor that I love in a two stroke. But it puts the power to the ground more. Depending on you riding still I wouldnt go in smaller than a 11oz.
Yes the Gnarly pipe. My dad had one on his ktm 300 exc. It add alot more bottom end power. I would go with the turbine core 2 silencer. The Q is very quite. Under 93 decibles but it might cut down on power. All you really need for a enduro is a spark arrester.
I am going to ad a 3.4 gallong IMS tank. Eventually some battery opperated lights.
My gearing now is a 14 and 50. It works ok but I have to use first alot and having to shift through N alot. Dead engine starts are really tricky this way. First is too much. But second gear I have to work the clutch alot.
I am going to drop a a counter shaft size down to 13 and see what happens.
18'' wheel I heard is a good thing. I dont plan on it until I break a wheel. With an 18'' you get a taller side wall, which makes it less prone to flats. The bike was desinded for a 19'' so it might make handle different.
-bryan

Bryan, I'd reconsider the 3.4 gallon IMS tank, unless nobody else makes one that is less bulgy.
My 3.1 (or 3.2?) IMS tank for my 2000 KX250 literally had wings sticking out over top of the radiator shrouds, it really got in the way, not to mention looked rediculous. It didn't make the seat curve up any more than stock, but it went straight up about 2 or 3 inches right at the front of the seat, so if you were bow-legged enough to not bash your legs on the 'wings' you would surely bash your other more delicate parts on the gas tank if you tried to get forward on the bike.

DTSViper,
I have had Clarke tanks on my KX's and the fit and finish are great. I have also owned Acerbis and IMS tanks on other bikes in the past and I can tell you from experience that IMS would be a poor choice. The fit and quality don't compare to Clarke. Ergonomically the Clarke is better as well.

On the Clarke, I was able to use one for a while, but it is was wider and it pushed the seat up alot! Made it harder to get on the front. Not that you needed to, because it held so much fuel.
On the Gas-Gas and KTM the gas tanks are the oddest shape, if you even wanna call it a shape. The go every where that there is the slights crack or bulge. They go down the side of the cylinder, down under the shrowd's (spelling) And down under the seat.

As for the IMS. I think there smallest tank is 3.4 ( I think) maybe 3.2 cant rember exact numbers. I sat on a KX with one with the IMS on it and it went mainly down around the cylinder and hung over the shrowds, but really didnt come on the seat. Ill have to look into that. Cargo down low is more important than extra weight!
-bryan

dtsviper, you have been given some great info. i also ride the TEXAS and SERA enduro events and never need lights. consider the extreme expense of the eline kit before you purchase something you do not need to be enduro legal. also the ignition cover bulges out a LOT and usually requires a aftermarket shifter that is not ergonomically correct. a friend had this kit and hated it because of this. he could not sell the kit so he sold the bike. think about it and try to ride a bike with this kit before buying. good luck.

You might want to look into what mountain bikers use for lighting.. High powered lights that you can mount on your bars, with batteries that last anywhere from 45 minutes to 2 hours. Much cheaper than putting a lighting coil on your bike, too.

Originally posted by dirt bike dave
... a well setup Japanese MXer doesn't give away anyting to the pumpkin or Gas Gas enduro bikes.

Click to expand...

I agree! Just to add some additional information, a firend of mine prefers the E-Line lighting coil over the add-on lighting coils. He contends after adding the E-Line coil he was able to remove the FWW. I rode his bike and it definitely didn't have the "hit" of a standard MX bike, but I'd still want a little smoother power for those real nasty conditions.

His KX was a '98 model. When he bought it the previous owner installed a FWW, not sure of the size, and powered lights by tapping into the power jet circuit. My buddy swapped over to the E-Line coil, but didn't mention anything about changing the shifter or the bulky ignition cover.

Personally I like the engine to be super smooth. A KX125 with a KDX220 engine would be my personal choice, but that's a lot more expensive than converting a MX bike.

DTS,

I just now got to read this thread, but I had a 2000 KX before I got my CRF. Actually it's the one OK KX'er is on! Anyway I have a 3.0 Gallon IMS tank left over if you're interested. It was much better than the 3.4 Cam mentioned (I had it also). The 3.0 has no wings and is nice and flat. Email me an offer if you're interested. mhill@mccmail.com

dtsviper; you hit my soft spot when you mentioned your son. detailing your kx is great but nothing compared to the happiness you will feel everytime you see your son smile while riding! i am sure you already know that. NOTHING is better. also, are the times the other posters show accurate. some of you guys have to be sick. when i was in the military i made a decision to be self employed. anything before 9 or 10 is brutal.