KDX versus KTM EXC? Experiences please.

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#1
I recently bought a 93 KTM 250EXC. I was looking for a KDX when I found this and read the KTM was about the same with a better suspension. I have no clue what's been done or if it is running correctly compared to others but I have a question. The bike isn't as mild as I would like, it will idle without stalling but it likes the pipe. When cruising a fire road it's hard to find a spot between lugging and redline to cruise. I realise most 2-strokes are this way but I was hoping. Before I go back to a 4-stroke trail bike is the power delivery much different on the KDX? Can you relax and ride the trail w/o being on the pipe?

Thanks
 

BRush

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#2
Yes, the power delivery is different on a KDX. It has a broad tractable powerband. It is an easy to ride trail bike and not (unless you modify it to be that way) a pipey rocket bike.
 

moridin

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#3
You pretty much summed it up. There are very few 2S bikes that have the usable power delivery of the KDX. I really like the older Yamaha WR's - they are very nice bikes. If you have the cash - a new KTM EXC300 is quite a bike. It has a ton of power all over the place - and when it is one the pipe - well hold on.

If you are looking for four stokeish feeling - but still want the snap of a 2S - look at the KDX220. Alot of stump pulling power on this bike.
 

canyncarvr

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#4
Jetting can change the attitude of your bike from mild to wild. Riding a 2-smoke and NOT being quite familiar with what it takes jet-wise is a large waste of time.


Well, unless you don't care how it runs.

The ktm250 is reported to be considerably smoother than it's younger brother (the 200). If it was a 200exc you were talking about...now THAT I could understand.

Do some research on your carb. It likely has a double taper needle in it, NOZH or somesuch. Something along the lines of a DEK (single taper) can be used in it's place. A number of ktm'rs have changed to the D needle for the express purpose of smoothing out their bikes.

Do some reading on the ktm board. If fishhead is still around, you may try a PM to him about it. He's not riding a 250 that I know of, but he's an orange kind'a guy.

If you are looking for smooth, no-hit broadband power...try a crf250x if you ever get the chance.
 
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#5
Thanks for the inputs so far. his weekend I'll check the needle and go one lean while I'm in there. The bike will run below the pipe but isn't extremely happy about it. I was riding a dirt road and finging a comfortable zone that wasn't screaming was hard. The bike does have less of a hit than the RM250 I had but I still liked the feel of my DR650 better. Maybe I'll trade down to a KDX or WR before going 4stroke again.

When riding a fireroad are you SUPPOSED to stay on the pipe? or lug it? Seems hard on the bike at redline with no real work being done to maintain speed.

Thanks
 
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#6
Dbeast said:
When riding a fireroad are you SUPPOSED to stay on the pipe? or lug it? Seems hard on the bike at redline with no real work being done to maintain speed.

Thanks
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ I'm not a huge fan of being "on the pipe" at all times---only when that power is needed. As a matter of fact, even with a top speed of 70+mph, I feel the urge to upshift at 50 plus and just have to smile when the realization of already being in 6th comes about! :eek: It may be a trail vs. mx mindset---or that I'm not a very aggressive rider or competing for a living. I'd be interested in hearing others comments concerning throttle position. When cruising I'm always a gear or two higher than I have to be while my mx buddy on his yz250 is thrashing his redline in lower gears. The only time I'm on it is when I need the power to snap the rear end out of a turn or wot to get to comfortable cruising speed---in otherwords, my kips aren't open most of the time.
 
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canyncarvr

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#7
re: 'The bike will run below the pipe but isn't extremely happy about it.'

Another ping on jetting......

I'm a bit familiar with the 200exc only because my riding buddy has one. I've ridden it in the past, but only for a few minutes at a time. I couldn't get off it fast enough! It put my arms to sleep in minutes, chain noise was ridiculous. It was a stink buggy ride I couldn't wait to get rid of.

Ran 'fer crap, too.

Then there was yesterday. I rode his exc for several hours. He was nice enough to 'loan' me a bike 'cuz my kdx is going on week five for being 'fixed'.

What a rocket!! The bottom end of the thing is incredible. It screams!! The lack of poundage (vs: the kdx) was a real treat! At speeds below walking pace on hills you would have trouble just standing on, the little punkin pulled as smooth as silk. Give it some gas and you would just 'go'! Front-end didn't come up unless you asked it to.

Yeah..it still has a 2x4 for a seat and the usd forks make the turning radius a bit wide. Still, it was great fun!!

What changed?

Well, a ron black massaged carb, for one. I know what the bottom end of this 200 used to be. Ron's modification helped it in a huge way!

A DEK needle for another thing. I preferred it much over the nozh (I think) it had. Seemed to run considerably smoother to boot!!

I was without my commonly used tweaker, so couldn't adjust the air screw (another circuit affected by the rb-designs modification) as finely as I normally would. Still, it was close enough to be a great ride.

Don't assume the needle that's in there is the best choice cuz, 'They (ktm) ought'a know what they're doing.' I got that type of response when I was trying to find out why kawi put a 4" steel tube in their forks.

That (response) didn't make any sense in that situation either.

Have fun!
 
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#8
Trade DOWN to a KDX!??!
You come here asking KDXers advise on a KTM then insult us by that comment?
Good thing we are nice guys. When you get the jetting squared away and you think the hit is still too lightswitch like, try a flywheel weight to smooth it out. It will aid in the low speed performance as well as mellow transition to the pipe.
 
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#9
Trade down meaning cheaper and less racey, not lesser.

The EXC is supposed to have a flywheel weight, it's supposedly the SX motor with a weight and lights. I should check to make sure it's there though but I'm pretty sure it is.

I'll check the rod and maybe the jetting this weekend. Is the powervalve adjustable in some way that can change the power characteristics? What jetting effects the mid power?

Anyone want to trade bikes for a few? Thanks for all the help so far.
 
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#10
Buy the way, it has an FMF Fatty pipe. It came with 2 others I need to did out. I think I have the stock one but one of the 2 had a big dent and I can't remember which one. Will the pipe make a major difference?
 
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#11
Dbeast said:
Trade down meaning cheaper and less racey, not lesser.

Anyone want to trade bikes for a few? Thanks for all the help so far.

Dbeast, you may have just discribed my wife. Now that wouldn't be a problem, but hey man, that's my bike your talking about. She ain't cheap, the KTM's are just overpriced, and she's plenty racey enough for the likes of an old fart like Fredette to win on. (You do realize I'm just having fun here right?)
Any time you are out to Northern California, let me know and I will let you spend a day on my bike, no problem.
 

fuzzy

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#12
As CC said, jetting will be your key here. The 250exc can be a very docile ride when jetted right. Awesome torque, and top end. Will only be electric smooth with carb work.

When comparing to a KDX it would be different if you were still shopping, but you own it already. That being said, I'd keep it at least until you have a chance to get the carb sorted out(this is something that will also be needed on a KDX or any bike for that matter). The EXC is arguably a better bike...Not that the KDX isn't a sweet bike either. :cool:
 

canyncarvr

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#13
The stock pipe on the 200 is far more tractable than the aftermarket FmF for that bike. Don't know how that compares to the 250. You can get the stock pipe undented. $50 at pacific crest pipe repair.

Yes, a pipe can make a major difference.

Sure. It comes 'with' a weight. Check with steahly for other weight options. Like skipro sez, it will help a good deal.

Again (another 200 comment) the exc I rode has a steahly. Without the RB modified carb and with no additional weight I don't see how the thing could be anything but useless in the woods.

Shouldn't this be over on the ktm board anyway? The guys that actually ride the thing should have some valid input.

While the '95% rider, 5% bike' idea may be a bit hyperbolic (not much) when it comes to 'better bike', exactly what you will get is an argument. I can't catch my riding buddy when I'm on my kdx and he's on anything....his exc or his crf250x. And if we traded bikes, I still[/c] couldn't catch him. Still, I'd choose the kdx over a pumpkin bike.

The 250 will work per your description. Tune it.

BTW, 'down' means down. Was a comment you could well have left out...it's a hand-biter.
 

Smokin Joe

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#14
For < $50 in Brass You'll be Grinnin'

DBeast- Don't give up on that white ghost yet! As others have suggested, your salvation lies in jetting. Go to:
Carb Parts Warehouse
which has a couple great charts for needles and has real good prices on jets.

Most likely, you have a dual or even triple taper needle which never worked like it was supposed to. Go to a single taper like the DEK or a CEK, the "D" has a 1.75 degree taper compared to the 1.50 degrees of the "C". I am sure that someone will correct me if I'm wrong but the "C" needle should result in a more linear power band. Go with the "D" to get clean jetting while still retaining a "hit". You will also need to go up a few on the main since the dual/triple tapers have a very thin tip so the fatter tipped single taper needs a bigger main to give the same amount of juice at the needle-to-main transition from 3/4 throttle.

Suggested Jets to start with

  • Pilot: 42 or 45 (get a 40 & 48 while your at it)
  • Needle CEJ, CEK or DEJ, DEK or even all 4 (the "J's" are richer being the next diameter smaller)
  • Main: 175, 178 (170 to 185 to cover all possiblilities)
  • Air Screw: 1 to 3 but try to find the needle / pilot combo that gets you the best idle / roll on with the screw at 1.5 turns out.
  • That should get you in the ballpark

Start with the needle (put in a 178 main to start). Get the 1/4 to 3/4 response you want by adjusting the needle clip. Then fine tune the pilot / air screw and go to the main last.

Good Luck!

Joe
 
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#15
skipro3 said:
Dbeast, you may have just discribed my wife. Now that wouldn't be a problem, but hey man, that's my bike your talking about. She ain't cheap, the KTM's are just overpriced, and she's plenty racey enough for the likes of an old fart like Fredette to win on. (You do realize I'm just having fun here right?)
Any time you are out to Northern California, let me know and I will let you spend a day on my bike, no problem.
KTM's aren't overpriced at all, you get much more value throughout the entire bike that is well worth the extra money. This includes DFii reeds, good handlebars, better rims, pipe, suspension, on and on and on, that is way better than parts on a stock KDX. I've already put into my KDX (bike and upgrades) what I would have paid for a '04 300 EXC and still haven't upgraded my front suspension and my KDX still can't hold a candle to a KTM, performance wise. KTM's are definitely not overpriced, KDX's are just cheaper (price and quality) and there is a price to pay for that. I love my KDX, but have learned that since money wasn't the issue, I should have gotten the KTM.