KDXRIDER.NET

Would like to know about how the KDX 200 power output is compared to the new 250 four strokes and say 125 2 stokes. Only mods would be pipe and jetting done to the KDX

That's comparing apples and oranges. The bikes you mention are mx bikes, the KDX is a trail bike. In the woods, with a competent rider, the kdx can walk a 250f pretty easily, and it has way more torque than a 125 2t. On an mx track, the mx bikes win.

Probably doesn't answer your question, but it's really not a fair question in the first place. Different bikes for different purposes.

I appreciate the response. I am aware we are talking about diff bikes and power bands. I am trying to get a idea of how the Kdx should run when running good. I'm a just getting back into the dirt bike thing. I raced for years. All though I did not expect a mx typ bike and I wanted something easier to ride hare scrambles with I was maybe expecting to much. I am just trying to gauge how the bike should feel. I have completely gone through the engine . Complete rebuild even though it didn't need it and I think I have the carb jetted close 150/42. Repacked silencer ect. I did notice my Kips may stick a little. It opens but hangs there a little long I think. I do not know if that would make alot of difference. Do the RB mods really make that much of an improvement?

pretty much an oxymoron

The RB mods make a nice improvement in rideability. They don't increase the total hp a whole lot.
For HS you will be at a bit of a disadvantage if the terrain is fast and open but have the advantage if it is tight and slow.

The sticky kips thing is aggravating. I bet it is a result of replating the cylinder. It won't fix itself. Do a little search on "KIPS sticking"

Thanks for the replies. Karlp I understand what you are saying and bought the bike with the assumption that tat would be the case. I thought it might be a little more though. It is definatly a great bike and for the most part am very happy with it. I will have to see if I find myself at a disavantage on our corses. Just for the record I am not a beginner.I have ben ridding in one form or another since 1970 and rode expert mx until the 90's. Hare srambles just seem to appeal to me right now. I do beleive that the bike has enough upside that most short comings can be made up by rider. I was just wondering if the bike should have more becuase I have never owned one. The plating is intresting since I did just have it replated. Got to look into that. Wibbens, I love good sarcasim, been guilty of it on many occasions, but I don't quit get your response. I must be a little dense today. Don't get me wrong not offened in anyway I am just trying to understand it so I can appreciate it. Thanks all

Wibbins nevermind I think I get it now.

IMO, a 125 MX, or 250F MX bike will pull much harder at the upper end of the rev range than the KDX was ever designed to. The KDX has a killer woods motor, which means it has a smooth, strong low end and a strong mid-range hit that tapers off smoothly, albeit a bit early. The MX bikes will have almost no low end, come on hard in the upper-mid range, and pull to the moon. MX bikes can be ridden fast in the woods with a very experienced rider on them. A novice/tired rider will suffer in tight terrain, though.

Also, the KDX motor being a "Low Rev" motor in comparison to an MX motor is the main reason they last so long before needing rebuilds. In my experience, a 125 MX bike will need service (piston, crank, rod) more than twice as often as a KDX will. I have no experience with the current crop of 250F MXers, and I am not very anxious to find out what kind of intervals and cost are involved in long term ownership of one of them.

I think the KDX is a little deceptive. It is a pretty competent bike.

10 years ago I was on an XR400 and racing three or four Enduros a year. I bought a KDX because the XR was getting old and wearing me out.
At first I thought I had made a huge mistake. The KDX felt very weak and slow. I got used to it and started doing some upgrades. I also started finishing Enduros in much better position. The KDX ended up with the RB stuff and KX forks and did great in our races. It turns out that it was quite competitive against any bike out there 2 hours into a race when all the riders are pretty whupped up.
I also rode locally with a number of card-carrying "A" riders. We have a 20 mile loop that takes the top guys 1 hr 20 min, me on the KDX takes 1 hr 30 min. That is a reflection on me, not the KDX.
Later I moved the motor to a CR frame. I was maybe just a couple of minutes faster on the hybrid but a lot less beat up.
Recently I bought an '08 KTM 200. Again, I gained just a couple of minutes and it is a little bit less work. Those "A" guys still dissapear into the distance.....

I'd rate the KDX motor performance at about 75% of a 250 MX'er

fwiw, many of the guys I ride with are on shiny new 450f's. I usually have not trouble showing them my rear fender when we're on the trails. With a wide and straight enough section, sure they can blow by, but I will catch them as soon as it gets tight again.

juliend wrote:fwiw, many of the guys I ride with are on shiny new 450f's. I usually have not trouble showing them my rear fender when we're on the trails. With a wide and straight enough section, sure they can blow by, but I will catch them as soon as it gets tight again.

Same here. I ride with guys on 250 2T's, 450 4T's, and a lot of KTM 200's and 300's. With my KDX200 I could hang with all but one kid in the tight stuff. They could walk away from me in the open stretches and through the whoop sections but I would catch back up as soon as it got twisty and tight again. The KDX, IMO, is a very capable bike.

The racing 4T 250's don't have much down low....They are too cammed out....It's all give or take. I think the 2-cycle does a better job at making at least 'pullable' power down low, and still rip up top over the 4-cycle....Esp if they threw some new tech at it. A variable valve train would enable the 4-cycle to do it better, but god help the owner of that wallet-buster.

My buddy has a 2007 crf 250r and it smokes my kdx all day. I have a rev pipe on it but never jetted it plus i weight about 100 more pounds but from a dead stop the only time i can get him is if i dump it in 2nd and he still passes me a few second later. But his bike is far from stock and has had many more trips to the shop than the kdx. haha the maintenance on them is ridiculous.

I've ridden a stock RM125, YZ125, and i currently own a KTM 125 EXC. All very fun and quick bikes, but the KDX has much more torque and midrange than the 125's. The power comes on quicker, but in a more broad and user-friendly way and is more predictable and controllable. Compared to the 125's, the KDX falls a little flat on top end. But that is fine, since if you are riding trails you won't be able to go WOP often. My KDX is an '89 model and has full FMF exhaust, power reeds, UNI filter, and is jetted a tad rich

Im curious to find out how well the RB mods work whenever i get the money for it