KDXRIDER.NET

Hi all! New to the forum, glad to be here.
A mate of mine has a 2004 kdx he is wiling to part with for a damn good price, and after looking at these hybrid build threads I am quite seriously looking at jumping into a project! Rough plan is to get hold of a rolling body Kx125 and putting the kdx engine in it after a cheeky rebuild.

This could cost up to $4000 nzd perhaps more, which got me thinking... how much different is the kdx hybrid to say the Ktm exc200?
There are a couple of exc's floating about for roughly 4k and look tempting.

I love motorcycle builds and think this type of project will be a blast, but at the end of the day is there much gained from all the work?

Welcome to the forums.

What is your intended use of the motorcycle, riding around or racing?

A KDX engine in a KX125 frame can be an outstanding bike. You'll still need to address the suspension but that's going to be true no matter what bike you buy. One thing you may get on the pumpkin that I at least would love...estart!

If you enjoy a project, working with your hands and want a unique bike - then definitely do the hybrid.

But . . . The KDX and the KX125 havent been produced in years. If you are looking to keep this long term, parts may become an issue.

I have had both. The KTM "out of the box" is considered to be a more capable bike. After owning the KDX for years I found the KTM to be more difficult and just different to work on. There was more power in the KTM, but the KDX has plenty and seems more manageable. At the end of the day, the quirky KTM had to go. Now my garage has an '04 KX/KDX hybrid and an '04 KDX 200 plated. Couldn't be happier and I do not miss the orange bike at all.

Sorry should have mentioned, my riding disciplines are enduro and cross country. Generally woods and trail riding in the weekends so not a whole lot of super fast open riding. Which is why the kdx motor is so attractive to me.
Also- I am 22, fit and only 67kgs, with about 10 years riding behind me, just in-case that is relevant to anything.

Suspension is not an issue, I have rebuilt forks and shocks in the past and have a pretty good idea on setting them up to my requirements. All else fails there is a suspension specialist just around the corner.

Pumpkins are indeed cool bikes! Purpose built, but the exc200 models within my price range don't have e start.
The power valve is adjustable on them too..

For my Kxdx build I am thinking of doing the reeds, thinner gaskets and pipe mods to wake her up a bit.
Perhaps set it to standard or slightly retarded timing to aid bottom end, hopefully not sacrificing top end too much.

As far as parts are concerned there are a metric **** ton of kdx's and kx parts floating around nz at the moment. Plus the kdx I am looking at purchasing comes with a whole second parts bike.

Another question that I haven't been able to find so easily, I imagine that most hybrids choose to use the 18" rear wheel?
Does the kdx rear bolt straight up to the kx swing arm or do you have to lace the kdx wheel around the kx hub?
I think i read somewhere there is one or two models that fit straight in, but there was no evidence or elaboration on it.
Also, are all kx125's steel frame? Is it ideal to go for a kx the same year as the kdx?
If not, what year is preference?

I'm using the search function, theres just so much to filter through.
I'm getting bloody excited about this haha looks like its a go!
The old man is stoked too because he used to race the old kdx back in the day.

Cheers for the help guys!

B737driver wrote:I have had both. The KTM "out of the box" is considered to be a more capable bike. After owning the KDX for years I found the KTM to be more difficult and just different to work on. There was more power in the KTM, but the KDX has plenty and seems more manageable. At the end of the day, the quirky KTM had to go. Now my garage has an '04 KX/KDX hybrid and an '04 KDX 200 plated. Couldn't be happier and I do not miss the orange bike at all.

Interesting! I have had a few Kdx's in the past and loved the power, but too me after going between mx bike and trail bike the kdx felt ergonomically wrong. I understand the kdx as is, is a totally capable machine

One thing about the ktm 200s is the terrible steering lock.
How is the handling on the kx? I see some people opt to use the cr body?

Yeahthebikes94 wrote:...Another question that I haven't been able to find so easily, I imagine that most hybrids choose to use the 18" rear wheel?
Does the kdx rear bolt straight up to the kx swing arm or do you have to lace the kdx wheel around the kx hub?

The KDX rear wheel bolts right on using the KX wheel spacers. Same size axle on both up through 2007.

Yeahthebikes94 wrote:Also, are all kx125's steel frame? Is it ideal to go for a kx the same year as the kdx?
If not, what year is preference?

Yes. Since you're transplanting just the motor it doesn't need to be the same year. Here in the states the 99-02 is popular because there are a crap load of 125s from that era floating around in pieces. Here in the states the 99-02 125s share lots of parts, the 03 was unique, and the 04-05 shared parts. Really it comes down to what is available.

One thing I hated on the KX was the steering locks, the MXr just didn't turn on a dime like the KDX and the lock to lock distance is smaller than the KDX. I just ground off some of the stops so I could turn the bars a bit further which helps in the woods. Just make sure you keep an eye on the frame/tank/fork interference.

2003+ KX is 25 mm rear axle, not 20 mn.

Thats handy, would be ideal to re use the kdx wheel.
So the kdx and kx share the same size axle up to 2002? Might be worth keeping an eye out for an 02 kx to save lacing a wheel.
In saying that if a more modern one shows up for the right price it may be worth jumping on.

Thats a shame about the Kx steering lock, did grinding the bolts make a massive difference?
From what I have heard the Rms have brilliant handling and turning circle, Ill do some research into what is involved with putting the kdx motor into one of those, just for science ya know

http://motocross.transworld.net/feature ... bZOy5eW.97

I retract my statement, it seems the cr's have the best handling and suspension for the 125's.
Interesting

The RM swap has been done and documented in the hybrids section. As has an aluminum frame if I recall. Correct about 2002, I was reading through my build notes and my chicken scratch 2 looked like a 7 lol
Grinding the locks helped a bit, but at the end of the day its a motocross frame with motocross geometry. It works well for me where I ride

Not sure about the 99-02 KX, but the '04 hybrid seems to be much closer steering lock wise to the KDX with conventional forks. My '04 KDX with KX fork swap needs a 4 lane highway to turn around. The hybrid, not so much. This was after adding to the steering stem stop to keep from hitting the fuel tank.

Ive been doing some thinking around the KX/Kdx axle diameter change from 2003 up, is there any reason why the kdx wheel can't be used by just putting in the right sized bearings in for the kx axle? This way you would use everything kx (wheel spacers, axle, adjustment blocks) with the stock kdx wheel.
There must be something I am missing?

Also, how does the Kdx wheel fit up to the Cr swing arm and axle?

After further thought, at this stage I am leaning more towards the KX chassis. Mainly because of the steel frame flex, welding ease, and everything matching kawasaki. Issues with the Cr apparently include issues getting to the carb, modification of the frame (in atleast one case), stiffer handling, and is a pain to weld if you don't know someone who can lend a hand on the cheap.

No reason if you can find the right bearings, not hard to figure out. The 2002 and earlier is a 20x42x12 bearing (6004X8JRLLX2/3A) and the 2003 and up is a 25x42x9 (69052RS), Same outer diameter, different inner for the appropriate axle. The newer bike bearings are a hair narrower (which is better than being wider) so you may have to fiddle with the spacers to get it right, but that is super easy.

Makes me wonder why in so many builds people spend the time and effort lacing a new wheel when simply ordering new bearings and minor messing around will work...
Cheers for the help there :)

A lot of times is because the info isn't easy to find, or sometimes bad info gets out there. Sometimes it's just because they have some sexy new Warp9 rims they want on there (who doesn't?). On the KDX-KX its a bit easier because the OD is the same, not always true when doing hybrids.

Just if anyone is interested here is the kdx I am looking at purchasing



and here is the kx I am viewing this afternoon https://www.trademe.co.nz/Browse/Listin ... 1424171328

Rode the kdx in a XC race over the weekend and it seemed pretty tight.
Will see what happens this arv with the kx!

So after sitting on it and waiting I managed to drive the seller down a bit.
Picked up this kx yesterday and went for my first ride on it today! Handles well and feels much more ergonomic than the kdx.
Took it through a tight wet forestry section and lugged it around, kept thinking god I wish this had a 200 engine in it.

Overall pretty happy with it, has a few niggly things being an older bike. Should be a bit of fun until I get the kdx engine sorted!

Little update, I blew up the clutch in the KX and seized the engine.
Tearing it down I found the cylinder is very thin on the plating, so Ill just throw in new bearings and seals and ride it till the top end gives out.
I have used a dremle to shape and cut back the turning stops, I have a turning range all the way till the forks nearly touch the frame!
I have also changed the radiator position by drilling and moving the braces, enabling me to move the top of the radiators back towards the tank. This gave me room to turn the forks further.

In the future this KX (turns out its actually a 2002 model) will need a fork rebuild with 2.5w oil, decent woods protection, new tires and tubliss system, and of course the kdx engine!

Meanwhile, I have the 2004 kdx waiting in a garage back in Wellington. Getting very excited to put this build together.