KDX220 vs. XR400

[xxrrider]

So I got my KDX220 - a 2000 in very nice condition - bone stock. Went riding yesterday and let a buddy ride my '97 XR400 - also stock, w/o baffle.

I started off on the KDX and was just amazed at how easy it is to ride and how much faster you can corner and run through sand whoops. It's also way easier/more stable to ride in loose sand.

Then we traded for a while. The XR is much more tiring to ride fast, and you can't carry as much speed (reasons above). However, it does have tons more torque than the KDX (dyno'd at 46ft-lb at the wheel!). After riding the KDX, the instant torque of that bike is really amazing. BUT - you can't use it for long unless you're in a really open area. Either bike will quickly get you going faster than conditions permit. The XR is better for turf/terrain destruction and road use. The KDX is WAY better for everything else, and much more fun.

As a matter of fact, my buddy who was considering buying the XR is now going to look for a KDX! - awsome bike!

 

[rethnal]

Plus you get to smell that awesome 2 stroke oil! :)

 

[Zerotact]

an XR400 is quite a tractor, but many times I have seen people drop them and then it takes a little work to get them started again.

 

[James]

However, it does have tons more torque than the KDX (dyno'd at 46ft-lb at the wheel!).

At what rpm?

 

[xxrrider]

The XR torque curve peaks around 3500 - 4K rpm. It redlines at something like 7500rpm and it's not making much power at that point. I'm guessing somewhere around 6-6500 is where you want to shift an XR. I'm tellin' ya it's total tractor. I believe it only makes around 30hp, maybe less. The amazing thing is that a WR4xx willl dog an XR400 - some of those new(er) water cooled thumpers must just be scarry.

I zipped the kdx around the open dirt roads today and the torque/power difference between it and the xr400 seems much larger than in the park yesterday where it was tighter - I might be getting that pipe sooner than I planned. But how much fun is it to ride 85mph on a flat dirt road on a big, heavy bike? - that's how you end up in the side of a car pulling out. XR might be better if all you did was open / straight fire road riding - but for the fun stuff, it's just no contest - the xr may as well be a road king in the whoops... Anyone know what a stock KDX tops out at?

Yup when you drop an XR, it's best to take a short walk and catch your breath - it needs to sit for 10 minutes. and yeah - that 2 stroke syn. oil actually does smell OK.

 

[James]

I don't think it is possible that it has 46 ftlbs of torque. Stock, it has about 28hp which means the torque would have to peak at 3000 rpm to get 46 ftlbs. I am pretty sure the rev limiter kicks in at 8500 and the peak is somewhere around 6500 rpm...so you might be right about the shifting. I had the White Brothers dyno for a while but I can't find it anymore.

I had an XR400 for a while. Would like to have that engine in a CR250 frame.

 

[KAY DEE EXER]

My 98 200 does 140kph with 13-49 gearing. The quickest Ive seen on my speedo in the bush was 100kph.

 

[xxrrider]

Yup - it makes about 27ft-lb and about 46 ft-lb at 3000 rpm. Total tractor. I'd still take a KDX any day of the week. There's an article on motorcycle.c0m comparing the klx300 and XR400 with dyno charts. Can't send link - darn spamkiller.

Wow - I'm (pleasantly) surprised that a KDX will do 140 kph (88mph) with just a little taller gearing. Is the bike modded? I saw an (indicated) 83mph on my XR

 

[James]

http://motorcycle.com/mo/mcdirt/klx_xr.html

WOW, I would have never expected a bike to peak so low

 

[xxrrider]

Yeah, riding that xr is totally different - it FEELS much faster due to all of that low end torque but after riding around a track yesterday, I realize that the KDX actually comes out of the corners just as hard if your in the right gear. Might also have to do with the fact that you can take corners faster with the kdx too. Either way, I have to put the trusty XR on the auction block.

I also found that while cruising on the road at a steady 35 mph (I got a plate for the kdx yesterday!) the kdx kinda wants to surge and doesn't like running at low, steady rpms. I guess I have to get used to holding the revs higher to smooth it out - just a different feeling.

 

[KAY DEE EXER]

Wow - I'm (pleasantly) surprised that a KDX will do 140 kph (88mph) with just a little taller gearing. Is the bike modded? I saw an (indicated) 83mph on my XR

OK OK... It was more than 130km/h though. It was going down a huge hill slip streaming behind a 450f revving its poor fat head off. Yes its slightly modded... V-force 2 and FMF system. Different jetting and needles changed her personalitty the most. No airbox lid. I was told by the previous owner that "the ports have been de-burred and cleaned up" but Im still not sure whether any of thats true.

 

[ABS13]

I also found that while cruising on the road at a steady 35 mph (I got a plate for the kdx yesterday!) the kdx kinda wants to surge and doesn't like running at low, steady rpms. I guess I have to get used to holding the revs higher to smooth it out - just a different feeling.

Be careful riding a 2 stroke at a steady road pace - best to vary RPM since these engines were made for off road use. Major difference from a 4 stroke.

 

[P455]

Be careful riding a 2 stroke at a steady road pace - best to vary RPM since these engines were made for off road use. Major difference from a 4 stroke.

I agree completely. Steady road speeds on a 2-stroke dirtbike are an easy way to melt a piston.

Check out why:

http://www.dansmc.com/seizure.htm

 

[adam728]

I also found that while cruising on the road at a steady 35 mph (I got a plate for the kdx yesterday!) the kdx kinda wants to surge and doesn't like running at low, steady rpms. I guess I have to get used to holding the revs higher to smooth it out - just a different feeling.

Wow, I got my KDX plated on Wednesday too! First road ride was yesterday, and I agree, it surges all over the place. I expected it and it doesn't bother me much, I don't plan on doing a whole lot of road riding anyway. Being able to ride your dirt bike through town rocks though! :aj:

 

[NM_KDX200]

Check your jetting on the surging- my 200 is really smooth on the road. I typically ride 3 miles down a flat dirt road to my little track and the 200 is very smooth. A clean KIPS will help a lot, too.