KX vs KDX - what's the difference?

Got questions? We got answers....
Post Reply
heckler
Member
Posts: 243
Joined: 11:15 pm Apr 06 2010
Country:

KX vs KDX - what's the difference?

Post by heckler »

I'm unfortunately looking to replace my KDX220 which I ride in the woods.

Not too many KDX's for sale in my area, but a few KX's - what's the difference?
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Post by Julien D »

the kdx is a purpose built woods machine, the kx is a purpose built mx machine. Worlds of difference in power, power delivery, suspension, the whole 9.
Image
heckler
Member
Posts: 243
Joined: 11:15 pm Apr 06 2010
Country:

Post by heckler »

so, don't even bother if I have no interest in riding on a track?
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Post by Julien D »

a 250mx bike makes a good woods machine, but it takes more work to get it there. The power is very peaky in stock form, and the suspension can be very harsh over the slower rough terrain. Needs resprung, revalved, flywheel weight, etc. If you're up to the task, the kx250 would make a great woods bike after modding. If you're looking for something like the KDX, but more, maybe check out some other enduro bikes. KTM's EXC models are excellent, and Gas Gas EC's are pretty sweet too.
User avatar
kawagumby
Gold Member
Gold Member
Posts: 927
Joined: 10:09 am Nov 30 2006
Country:
Location: California

Post by kawagumby »

I've converted several KX's for off-road. The biggest drawback is the close-ratio tranny IMO, which requires you to gear down for tight woods work - then your top speed is fairly slow, relatively speaking. If you don't need a lot of top speed - adding just two teeth to a stock rear sprocket will usually get the job done for trail work. For me, the stock fork spring rates are right on, but you will need to at least remove some shims from the fork compression stacks. My experience is that the rear shocks usually don't need internal tweaking to work in the woods. You will need to add some flywheel weight, and mostly you will need to learn throttle control, LOL. Most mx'rs use a 19 rear tire also.
A side stand is needed too, unless you have a lot of trees to lean against.

For just mild, fun, trail riding an MX'r sucks, but if you are an aggressive rider they are the ticket. An mx'r tends to tire you out more quickly in tight single-track situations, IMO.

As far as power delivery, most modern 2-smokes are pretty linear - and don't have a big hit as in days of old. The last kx I converted was a 2001 and the engine was predictable but hits harder everywhere than a kdx.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Post by Julien D »

I get a lot of seat time on an older yz250 the last couple years. No flywheel weight, stock fork/shock both rebuilt, and a fresh engine with a PC pipe. That thing rips. Kawa is right though, it wears me out really quick. A bit of whiskey throttle in a tight spot and i'm on my back wondering what happened. I love that bike though.... Trying to talk my buddy into a flywheel weight for it. Maybe I'll just have to buy him one.....
Bouillion
Member
Posts: 119
Joined: 08:56 pm Apr 10 2010
Country:

Re: KX vs KDX - what's the difference?

Post by Bouillion »

>|<>QBB<
heckler wrote:I'm unfortunately looking to replace my KDX220 which I ride in the woods.

Not too many KDX's for sale in my area, but a few KX's - what's the difference?
What's wrong with the 220 motor on your KDX?
heckler
Member
Posts: 243
Joined: 11:15 pm Apr 06 2010
Country:

Post by heckler »

it's a painful story that starts with me not noticing the VIN had been ground off when I bought it.
User avatar
frankenschwinn
Supporting Member II
Supporting Member II
Posts: 482
Joined: 01:20 pm Nov 28 2009
Country:

Post by frankenschwinn »

That sounds like a story we need to hear...
User avatar
David_L6
Gold Member
Gold Member
Posts: 235
Joined: 01:07 am Jun 04 2010
Country:
Location: Northwest Louisiana

Post by David_L6 »

>|<>QBB<
kawagumby wrote:I've converted several KX's for off-road. The biggest drawback is the close-ratio tranny IMO, which requires you to gear down for tight woods work - then your top speed is fairly slow, relatively speaking. If you don't need a lot of top speed - adding just two teeth to a stock rear sprocket will usually get the job done for trail work. For me, the stock fork spring rates are right on, but you will need to at least remove some shims from the fork compression stacks. My experience is that the rear shocks usually don't need internal tweaking to work in the woods. You will need to add some flywheel weight, and mostly you will need to learn throttle control, LOL. Most mx'rs use a 19 rear tire also.
A side stand is needed too, unless you have a lot of trees to lean against.

For just mild, fun, trail riding an MX'r sucks, but if you are an aggressive rider they are the ticket. An mx'r tends to tire you out more quickly in tight single-track situations, IMO.

As far as power delivery, most modern 2-smokes are pretty linear - and don't have a big hit as in days of old. The last kx I converted was a 2001 and the engine was predictable but hits harder everywhere than a kdx.

That post sums it up well.

I have a CR250 for woods / trail riding. To get it set up for woods / trail riding I had the suspension re-valved, went up two teeth on the rear sprocket, installed an FMF Gnarly pipe and added a flywheel weight. I had it re-sprung too but that was for my weight (~210 lbs) and the weight that I added to the bike with an oversize gas tank, skid plate, bark busters, etc., not so much because of where I ride. All that suspension work, pipe, gas tank, and flywheel weight = $$$.

I now have a KDX200 also (currently being completely rebuilt). I've ridden the KDX only a little but I liked it a lot. I've been on MX bikes for a long time. It's not all that cheap to tame down an MX bike for leisurely trail riding. Better off buying a KDX to start with than trying to turn an MX bike into something similar to a KDX.
2000 KDX200 / 2002 CR250 / 2003 CR250 / 2008 TT-R230 / 2011 Brute Force 750 / 2012 Brute Force 750 EPS
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Post by Julien D »

I agree, kdx is an awesome base to work from. I would also consider an older RMX250, if I could find one.
Image
User avatar
jlove1974
Supporting Member
Posts: 76
Joined: 08:07 am Jun 15 2010
Country:

Post by jlove1974 »

not to mention that every ten year old MX bike you find for the same price as a KDX is going to be a CLAPPED OUT POS!

many times I'll see KDXes cheaper than MX 250s and they look almost brand new compared to the other POS for the same price.

Only KTM I would consider is an 200SX or a 250EXC to replace my KDX220
Post Reply