2001 Cr-kdx200

[ebeck]

Here is my 03 KX125 with KDX200 motor so far. My 02 KX/KDX has been done for about a year.

 

[SVandal]

No a belt sander would be fine, i'm just a machinist and just use to going by a drawing and doing with a mill.

No worries, I've done both (except for the tig welding) and find with welding that thousandths of an inch no longer matter as long as the holes line up. :) Thats one of the hardest things for a new Mech Eng to learn when designing for welders ( and machinists for that matter).

I just wanted to be sure as I had been using the sander to prep some metals at home for welding on my street bike.

The bike is looking good! Is there a noticable difference between the kx/kdx and the cr/kdx? Is one preferable over the other? Thanks.

 

[legendboy]

Curious, why use a mill to bevel when a belt sander would do the job a whole lot faster? Is there that big of a concern about weld contamination from the sand on the belt?

No a belt sander would be fine, i'm just a machinist and just use to going by a drawing and doing with a mill.

It kinda depends on what your welding. For something like my frame mounts, where i can hit it at max heat the prep work can be minimal.

If i were welding up intercooler end tanks or 16/18 gauge aluminum tubing I would follow a whole different prep. Smaller tungsten, with a fresh ball on the end, very careful not to use any sort of abrasive because it will contaminate (stainless wire brush only), and i always treat the weld area with acid no more then 15 mins before i weld.

I am no welder, or machinest, just a hobbiest. For years I use to build custom turbo kits locally, but then the childrens came..... LOL

Here are a few more examples of my tig welding.

http://www.telusplanet.net/public/kaake/welding thread/

 

[legendboy]

Anyhoo back on topic, i didn't get too much done this weekend. I have the motor mounted, carb on and it looks like the stock CR airbox is going to fit!!! haha woot!

 

[SVandal]

You call those good welds??? Theres nothing there to grind down :).

 

[karlp]

I had to use one of those fancy Fredette kickers. The stock one was just not going to clear the frame.
It might on your frame.

 

[legendboy]

You call those good welds??? Theres nothing there to grind down :).

:laugh:

I had to use one of those fancy Fredette kickers. The stock one was just not going to clear the frame.
It might on your frame.

ya i better get my butt in gear and figure out something for a kickstart, i heard the kx125 kicker works on the kx/kdx bikes, wonder if it will work on the cr..... the stock kdx kicker is way too long to fit


I got my pipe done last night, didn't take a pic tho. Was a peice of cake :cool:

 

[karlp]

I've also heard the KX kicker fits, but can't verify it. I had a '95 KX125 for a while and it DID NOT fit the KDX, not the splines nor the lever swapped on to the KX knuckle.

 

[legendboy]

dang

what years fit the kdx?

 

[SVandal]

I believe it is the 89 style that just the lever will swap, not the mount, and then it is 2003 and up where the whole thing swaps (also I believe that 83-84 also fit). Don't quote me though as I haven't looked at it in a while. Maybe we could start a couple of threads that have this kind of swapping info on them for kickers, frames, and forks.

 

[ZOMBIE666]

Great job legend! that thing will be bad ass when its all finished

 

[legendboy]

Pics of the pipe

 

[karlp]

Very nice
Intake-motor-exhaust: It'll work

Nothing else but a couple of details....

 

[egmike]

lookin good :cool:

 

[SpeedyManiac]

Is that the KDX exhaust or CR125 exhaust? If it's off the 125, you may want to consider using a pipe designed for the 200...

 

[legendboy]

yea, i will give this a try first, see how it is. if it sucks then i will buy a kdx pipe and try and make it fit

 

[karlp]

I suspect it'll be O.K.
The carb on the CR125 was close to the same size as the KDX, the CR was a revver- I bet the volume of gasses flowing is pretty similar. You've added a straight to the inlet of the CR pipe to help at the bottom end.
I know on mine I'm using a '96 CR250 pipe that I added a KDX snout to. The motor runs great, I couldn't ask for a better running motor.
It WAS a crap shoot, though. Have to compromise between what you've got, what your willing to spend time and money on, and what fits.

What fun!

 

[legendboy]

I would be willing to sacrifice top end for low end grunt, but i really don't know enough about 2 stroke pipe tuning to have an opinion on what i have created.

the kdx pipe is definitely longer and wider.

 

[SVandal]

Correct me if I am wrong, but length gives you the timing for the return pressure wave, and width may be for the larger wave lengths (low RPM range) to allow more expansion and possibly a faster expansion. I didn't pay enough attention when we covered waves in physics so I am most likely off on this.

 

[legendboy]

Didn't get too much done tonight :(

Cleaned my carb up and mounted, mounted the cap and slide on the CR cable, only minor mod needed for that to work.

Then i started fitting the clutch cable. It is about 0.9" short adjusted all the way and is gonna be a bit more work.

 

[ebeck]

That pipe is way off, it is a 125 pipe, you can see the length difference. I'd look for a KDX or KX250 pipe. It may work for you though.

Just realize it WILL COMPLETLY change the character of the KDX motor. Enough that one would wonder why go to all the trouble to then loose what the motor has to offer.

 

[legendboy]

That pipe is way off, it is a 125 pipe, you can see the length difference. I'd look for a KDX or KX250 pipe. It may work for you though.

Just realize it WILL COMPLETLY change the character of the KDX motor. Enough that one would wonder why go to all the trouble to then loose what the motor has to offer.

hmm not necessarily. its really something that needs to be tried to feel the outcome. in reality, it may not be all that much different.

if it is no good, i only have about 40 minuites of work into it so no big deal.

 

[blackduc98]

Here is an article by Gordon Jennings that should give you an idea how pipe geometry affects motor characteristics:

http://www.bridgestonemotorcycle.com/documents/do_you_really6.pdf

 

[ebeck]

hmm not necessarily. its really something that needs to be tried to feel the outcome. in reality, it may not be all that much different.

Ohh, to the contrary, necessarily. It will be different. Pretty awful actually. On a 2 stroke the pipe is everything and that is not Hyperbole. Of course you may not know unless you have ridden a KDX with the correct pipe. It will work but it will not work well. the question is how do you know it is not working well if you have nothing to compare it to.

if it is no good, i only have about 40 minuites of work into it so no big deal.

Very true. Would be neat to do jsut to see first hand. :cool:

 

[legendboy]

Ohh, to the contrary, necessarily. It will be different. Pretty awful actually. On a 2 stroke the pipe is everything and that is not Hyperbole. Of course you may not know unless you have ridden a KDX with the correct pipe. It will work but it will not work well. the question is how do you know it is not working well if you have nothing to compare it to.

well riding a kdx200 for the last 3 years ought to give me a pretty good benchmark :cool: