Power on the 03 kx 250

[bigred455]

I put some good time on my 03 the last 2 weeks I have really no complaints about the suspension.I have been riding my 00 kx250 to just check the motor work I performed. So now I have some good time on the 03 In all kinds of situations.It does have good bottom,but not a hard pull grunt bottom,The mags are totally wrong when they say you can short shift the kx, that is the farthest from the truth.If you grab 3rd early, I mean 3/4 into the rpms in 2nd and grab 3rd the motor does not wan't to pull it I am not talking about a tight corner either,it does not wan't to get on the pipe, even with aggressive clutch work.The mid is speedy and fun,but the kx does not pull hard and through, infact it is too smooth, especially in sand sections.I would think if you can't pull 3rd or 4th early, the motor should pull pretty deep ,but that is not the case.It is great in tight sections following short straights,but when it comes down to getting some hard pull out of the motor coming out of a sweeper then a decent sand straight, you have to be very careful on your gear selection I mean perfect.The motor is coming out tomorrow.

 

[fastbygaff]

I have the 02 KX250, wich the motor is of a different design but think there is just minor adjustments you could make to get what you want.

From what your saying the transition from low/mid to top isn't what you want. Just a mier adjustment of advancing or retarding the timing will inhance either the lower grunt or the top over rev. Also a little dialing in of the jetting may give that one extra HP in the span your talking about. Or just V-force reeds will put you in there.

But smoother the power transfer means less wheel spin and less fituge.

But truly it's your riding style that doesn't match the machine. I seen the porting stats for the 02 and 03 team green has went with. It's not all that impressive, but you may like a top end machine, I just realy don't.

 

[SPR]

I have a 99KX and installing a RAD Valve and PC pipe helped the engine heaps. Port work is better I guess but I'm no Pro rider and have trouble riding it now. The RAD and PC pipe gave the bike much improved mid and actually had some good over rev (stock it just hit a wall up top). The 03 is not much different from the 99 engine design I think, the best change is the new cylinder coating, much better than the crappy electrofusion on my engine.

 

[Lissa]

I've spent a massive amount of saddle time on my '03 KX250. Heck, on Sunday I rode a 80 mile dual sport on it (all sand too). I have no complaints with the motor. Motor wise the only thing I changed was the gearing, flywheel weight and the silencer (Q-series). The expansion chamber is stock as well as everything else. The gearing change helped alot, it put the power right where I needed it, way low down. Granted I'm dodging trees, though.

 

[bigred455]

I have noticed that the arm that hooks onto the wheel to operate the powervale is a lot easier to pull back and disconnect YOU CAN DO IT BY HAND. It only has 1 spring compared to 2 in the past,it is softer. The front and rear tranfers along with the boost port are not being uncovered fully when the piston is BDC. About 2 mm of the bottom of the port windows the piston is 2 mm above when BDC. I did notice though that the transfer windows are vertically longer though than the past,so I am guessing this was done on purpose. The piston is perfectely flush with the exhaust when BDC. So instead of going crazy with raisng the cylinder to bring up the transfers and losing big time bottom end I am leaving them alone. The tunnels needed a lot of cleaning up, the boyesen ports were uneven and wavy. The power valve sub port windows needed cleaning up also. My squish was 1.4 mm that is going to be closed up, the head volume was 22.6 I am going to return that after the squish is brought down.I will hopefully pick up 3 hp with the squish and light porting I did. I must say the new plating is awesome looks very solid then the electrofusion, excellent chamfer to all the ports, overkill if you ask me.I will see how it pulls, I still beleive I may have to go up 1 or 2 teeth in the rear so 3rd is not so lazy when shifting a little early,you really have to be perfect between 2nd and 3rd.

 

[KaTooMer]

Shhhh...don't tell anyone, but I am considering switching from orange to green/yellow/red/blue. Got thoughts of turning a motocrosser into a hare scrambler. For those who ride the '03 KX250 in the woods, how do you like it in comparison to other MX'ers? What suspension shops do the best job on making the KX worthy in the woods? Anyone tried the Eric Gorr big bore kit?

Thanks.

 

[Lissa]

My boyfriend and I both compete strictly in enduros and have had several converted MXers. My current ride, '03 KX250 has been by far my favorite off-road weapon. KX's and YZ's are easy to convert to off-road weapons. I have never converted a RM, but they too seem to make very competent off-road weapons too. CR's can be converted to off-road but will require more cash to equal the other machines in off-road prowless. My '00 CRE250 was a great bike, but my KX was a lot easier to make work off-road.

Anyway, for off-road competition I'll only use Works Enduro Rider (WER) for my suspension work. They do cost a little more then some companies, but I have never had a problem, ever, with their set-up of my bike. Their valving and spring rate selection is right on. The suspension action is like magic and only requires a few clicker adjustments to go from sand whoops to nasty rocky trail. Great stuff!

The KX makes a awesome woods weapon! It needs very little dialing in to be right on off-road. Expect to purchase bars, barkbusters, 51 th R. sprocket, O-ring chain, silencer, 11oz. flywheel weight, and Suspension work. Everything else is optional (skid plate, 18in R. rim, etc...).

 

[roosteater]

off topic....but am I the only one here that thinks that Lissa might very well be the perfect woman? :laugh:

 

[Nevada Sixx]

the mags also suggested extra tooth on rear sprocket to close the gap between second and third gear. They also recommended a pc pipe..
fmf gives you a washer or something that goes on the rod that pulls the powervalve, when you buy their pipe.. i guess it holds it open longer or something. I am waiting for the 04 kx250, unless i break down and get the 01cr250 carryover at the shop.

 

[smarttoys]

I think you would be happier waiting for the '04 KX250 rather than getting the holdover '01 CR250

 

[motometal]

Lissa is cool, but she would be cooler if she liked the CRs better! :laugh:

I love my '03 CR in the woods, plenty of bottom end and the handling is tops.  Very light feeling bike in the corners.

 

[bigred455]

The 03 kx 250 is here to stay.... :yeehaw: :yeehaw:

 

[Rcannon]

Can you imagine walking into your house at nite and finding your wife cleaning air filters?  "Oh, hon, I hope you dont mind....I cleaned yours while I was at it>'

 

Or, Hey hon, so-and-so cycle is having a tire sale.....

 

Perfect?  She must be darn close!

 

[Smitty]

Originally posted by bigred455
The 03 kx 250 is here to stay.... :yeehaw: :yeehaw:

So I guess you've figured out where the power is, what's the trick?

 

[motometal]

actually having a spouse that was a dirt biker might contribute to me getting major burnt out on the sport.  I'm part way there already, but mixing it up with a bit of street riding and other hobbies helps. 

 

[TheJunkMan]

I have a 02 KX 250 and My powerband goes sumethin' like this A big hit in the transition from low to mid pulls really fast and seems to fall off short at the top So I short stift it It is real peaky. the motor is stock (with a fmf Q silencer) stock Pipe and Race Tech progressive springs (softer) and a lowered subframe My friend has a 98 Cr250 and the motor is really slow reving but will rev farther than my KX

 

[Lissa]

Stop flattering me! About CR's, green is more becoming on me. :) Especially that explosive low-end hit my pipey green machine has, much better suited to my riding style.

I've dated guys that didn't ride and it never worked out! they'd sooner or later belly ache about me riding and not spending time with them. My boyfriend now has been riding and racing for quite a long time and we complete each other. I'm a pain in the a** and he deals with it!  :) Ride together, stay together. 

 

[micg]

big red, I take it your porting worked. I couldn't agree with you more on the stock powerband, it was unraceable. The FMF Factory Fatty made it raceable the powervalve shim helped more the V-Force Reed made the power very, very good with no reason to change gearing.

 

[micg]

big red how did you close up the squish, and keep the head volume the same, and what measurement did you close the squish to. I saw the ports were sloppy but am waiting till I wear out my first piston.

 

[Lissa]

Why not just play with the final gearing? It's the cheapest way to alter were the power is delivered in each gear.