Kdx 200sr

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#1
Hi, this is my first post to this forum.
I have recently brought a 1990 KDX200SR. The problem i have seems to be parts. I recently ordered a rear box (spark arrestor) for a KDX 200 E2 which i presumed was the model i have. When the box arrived it was completely the wrong size for the fixing brackets.
Has anybody had previous experiences with this model?
Apparently it is the jap street legal version?
:cool:
 
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#2
I have an E1 model SR (Japanese domestic, street leagal model 89', with conventional forks).
The SR model here in Japan has a longer subframe, extending to the end of the rear fender. The silencer (rear box, hehe) uses part of this subframe for its rearward mount. The "R" model (racer) subframe ends just beyond the seat mounting bolts.

See the Parts Diagram for the "R" model.

In order to mount the "R" model stock or aftermarket silencer to your "SR", you will have to modify the mounting positions or make an adapter plate (cheesy fix).

If you don't have need of a spark arrestor, you can make a fairly good silencer out of your stock "SR" unit like I did.

Simply cut off the end cap and remove the stock barrier... err, silencer core shorten the body to desired length and then make a new straight through core out of punched steel sheet (roll it on a piece of pipe and tac-weld it). Remove the stock joining pipe (the piece the connects to the expansion chamber) from the canister and attach your new core. Reattach the canister, pack it with fiberglass and attach the end cap with rivits. There is a small pipe on the end cap that you should fit into your new punched steel core. I cut off the external portion of this pipe and made it look like a FMF silencer (sticker was a gift from a friend :) )

Here are some snaps of what it will look like. Yeah, I know I should have polished it up for the pic...






Other info...

The main differences between the "SR" and the "R" KDX "-E" series that I am aware of are the SR has...

Longer sub frame, Key/switch mount under seat, handlebar lock.
Steel fuel tank.
Wider ratio transmission (need to confirm)
Softer springs and valving (fork inner tube and damper rods are different on the 89' conventional forks as well)
Smaller carb (28mm)
Smaller airbox and manifold.
Different porting
Different head
Oil injection pump with reservoir tank under fuel tank.
Lower cut seat.

I just bought an E1 "R" model through the Japanese Yahoo auction and am waiting to pick it up :) I will be converting my SR to R specs as soon as I get it
 
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#3
You have been a great help Kipmax, thx.
What do you know about the front pipe?
Mine is looking a little worse for wear at the moment and will need changing soon. Will i need to order one specifically for the SR model?
Also, the bike seems to vibrate a lot, any ideas?
:)
 
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#4
Originally posted by Wevski
What do you know about the front pipe?
Mine is looking a little worse for wear at the moment and will need changing soon. Will i need to order one specifically for the SR model?
:)
Well, the SR expansion chamber and cylinder uses a bolt down flange while the R model uses springs. You may be able to find an after market pipe specifically for the SR (we have many here in Japan) but I went with a R model Pro Circuit pipe that had been hanging on the wall of my friends bike shop for years :) I had to cut off the stock pipe's flange and weld it to the Pro Circuit pipe. I could have had an adapter flange machined and attached with springs but the bolt on type makes for a better seal (no black gunky goo oozes from the exhaust port). With minor jetting adjustments the bike runs very strong (as strong as it can with a 28mm carb...)

Before I located the Pro Circuit pipe, I tried modifying the stock pipe by removing its inner wall and baffling material as described on the Just KDX pages. Note.... This does not work for the SR!!! :scream: The SR pipe has much heavier noise reduction and a larger diameter outside wall. You will end up with a KDX that runs like an RS125 road racer (screams on top, nothing in the middle and down low).

Also, the bike seems to vibrate a lot, any ideas?
Well, the SR does vibrate a bit more than some of the other Japanese "Dual Sport" two strokes simply because it is so closely related to its racing brother (no balancer shaft, rubber mounts). However, if you feel it may be extreme you may have bad crankshaft bearings... :(

Mine did when I got it. It had been ridin mostly on the street and probably spent a lot of its time in the upper RPM range. It also had about 23K kilometers on it.

Pull off the generator cover and check if the cavity is black, wet and oily. If so, the crank seal is letting fuel blow past due to the bearing's wobble. You are looking at a major overhaul in that case.

If you can rebuild it yourself, the parts are not much of an expense. However, good luck in spliting the cases! Mine felt like the had been welded together!

Hopefully your vibration problem lies somewhere else. Make sure you check all the engine mounts for tightness too.
 
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#5
You really do know your stuff!!!
According to the previous owner, the main bearings were replaced within the last 6 months. It may just be a case of "its the norm, get used to it!".
Seeing as you have loads of exhausts over there, i don't suppose you would like to send me one!!!?!! ;)
I've been checking over the bike today as i have an enduro race on Sunday. I found to my horror that both the front and back pads are shot. A local dealer has some pads luckily. I just hope they are the same!
I had a ride out on Thursday and the bike did all that i asked of it, (except stop!!) It does tend to smoke a little tho. Maybe a little tinkering with the carb will sort that out.
My version has upside down forks, is this common for the year and why did they only use them on this model?
Cheers again
Wev
 
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#6
Originally posted by Wevski
According to the previous owner, the main bearings were replaced within the last 6 months.
Great! However, I would make it a point to pull off that generator cover and check on a regular basis. Depending on how bad the bearings were when they were replaced the crankshaft may have been tweaked out of balance. This will cause vibration, and the premature failure of the new bearings. Just look for that wet (usually black) seepage around the crankseal. If you have problems again, the crank will need to be trued the next time you change the bearings.

Seeing as you have loads of exhausts over there, i don't suppose you would like to send me one!!!?!! ;)
Well, I suppose I could but I really don't think you would be happy with the cost, doubled with the shipping. You could surely modify an "R" model Pro Circuit or FMF pipe much cheaper! And you would probably end up with a better pipe. Just locate a good welder or machinist and either modify the pipe or make an adapter flange. If you really want me to send you one, send me an email (mine's in my profile) and I'll look into it.

I've been checking over the bike today as i have an enduro race on Sunday. I found to my horror that both the front and back pads are shot. A local dealer has some pads luckily. I just hope they are the same!
They should be the same. :)

It does tend to smoke a little tho. Maybe a little tinkering with the carb will sort that out.


What kind of oil are you using, and are you using the injector pump or pre-mixing?

My version has upside down forks, is this common for the year and why did they only use them on this model?
The Japanese SR and "R" went to USD forks in 90' as everyone was crazy about their looks. I believe the US Competition model remained with conventional forks (as did the KX's for a while). Funny, the conventional forks came back along with the perimeter frame...