1989 KDX 200 Basket Case Project

[david]

The chain is stretched out, that is why it is climbing up the teeth of the sprocket.

[Thrahl]

Haven't updated in a little while because I have just been doing small stuff not worthy of an update by themselves.
I made the top engine bracket out of aluminum since it was missing. I will be getting proper hardware for it soon.


Since the top of the air filter box was missing I threw some metal screen over it just to keep a little more stuff out.


I did a lot of just general cleaning. Wire wheeled the exhaust to bust most of the rust off.

Looks pretty decent now aside from the dents which I may or may not attempt to torch out.

My grips and throttle cable came in the other day so I got them all installed.

I have an issue with the throttle cable though. There is supposed to be a little elbow/collar things on top of the carb but since mine is missing I will have to rig something up for that. Shouldn't be too hard.


Also got the plastics cleaned up. The PO had painted them a darker green at some point and then spray painted half of them black over that. The dark green stuff was really stuck on there but some elbow grease with a razor blade got everything off eventually.


I kind of like the big hole in the front fender. Looks like a gun shot.

I also was able to pick up a used set of kx500 rear/side panels in white off of eBay for I think a really good price. ($25 shipped) Those should be here sometime this week or next.
I am also working on recovering the seat. I am attempting to do it without a premade seat cover but the horn on this seat is so tall it requires stitching so we will see how that goes. I may just pick up a cheap gripper cover for $25 on eBay.

My stator coil finally came in today too.

Got it installed and did get the bike to start and run a little bit but it didn't idle very well and then it would randomly just blast to 100% throttle, making me jump for the kill switch super quick. The carb is definitely going to need some attention and I may end up just selling this one (Mikuni VM32 I believe) and getting a PWK35 if I can't make due.

Question 1: When I was trying to start it, it took a lot of kicks and would often "kick back" really hard. Is this "kick back" normal?
Question 2: When I pull the plug and kick it over, the spark is very faint and I can't really tell the color. I am used to seeing a fat blue spark. Is something wrong?
Question 3: This one may be related to question 2. Does the source coil go in the top mount on the stator or the bottom or does it not matter? The two mounts have different heights so maybe since I put it on the lower top mount it isn't making as good a spark as it should?

Once I can get it running somewhat consistently I will order up the air filter, rear fender, chain, wheel bearings, front master cylinder, and silencer making this a complete bike ready to ride.

[SS109]

Questions 1, 2, and 3 are all related IMO. The timing is off. The shorter stator mounts are for the lighting coil and the taller ones for the source coil. So, yes, your source coil is mounted in the wrong location.

[Thrahl]

Questions 1, 2, and 3 are all related IMO. The timing is off. The shorter stator mounts are for the lighting coil and the taller ones for the source coil.

Oh ok well that is good (I think). The service manual doesn't specify so I figured it might not matter and just went with the more convenient one.
I don't know about 2 strokes but 4 strokes can get seriously screwed up if the timing is way off. Will the bike be fine?

Anyway, when I get off work tonight I will use my brand new flywheel puller I got in today and change that coil position. Hopefully I can get her to run at least consistent even if not correctly.

[SS109]

Yeah, a 2T will be fine. Hell, they have even known to run backwards! Put the source coil in the right spot, check that your timing marks are in the range they should be, and that the woodruff key is in good shape, and you should be good to go.

[Thrahl]

So I got home and worked on it a little more. Switched the coil position to the bottom one. Cranking it over seems to give better spark, it's hard to say though because it was night so it obviously is going to be a lot easier to see.
Kick it over and over and got nothing. Hit it with a tiny bit of ether to coax it started and it just slams into the limiter again.
Wait a few seconds for my nerves to settle (full throttle with no muffler is extremely loud) and give it another go.
Only took 1-2 kicks and it just goes full throttle again. I don't know if it was the starting ether making it rev like that or what but I can't be trying to mess with this thing at 9:30 at night. My neighbors would kill me.

I'll give it another go tomorrow but if it goes apeshit again i'm gonna take the carb off, measure it to find exactly what size it is (I know it is a Mikuni VM, I think a 32), and see what size jets are in it.
I guess these VM carbs were run on both 2 strokes and 4 strokes but the jetting, slides, and needle were different so I guess I better make sure I have a 2 stroke one.

This is really bumming me out because if this carb is no good, a PWK35 on eBay is going to cost ~$200 at least and I am just not willing to spend that much, especially if I don't even know if it is going to run properly even with that carb.
Add to that this VM carb is only worth ~$50-100 max.

[Thack]

You may have an intake leak. Somewhere extra air is getting the carb joint or intake joint. Maybe the slide is stuck open?

[SS109]

I agree. Sounds like an air leak somewhere. Check to make sure the slide in the carb is closing all the way to the idle stop screw. It does have a spring on it to help it close, yes? What shape is the intake manifold (rubber piece that connects engine to carb) in? Is it all cracked up?

You know, I have an old PWK carb sitting around. It isn't in the best shape (slide is rough) but it ran fine on my bike when I pulled it. We might be able to work out an affordable deal on it if you decide to go that way.

[Thrahl]

You may have an intake leak. Somewhere extra air is getting the carb joint or intake joint. Maybe the slide is stuck open?

As I was researching last night about it people were saying the same thing. Is it different with 2 strokes because my old 4 stroke had some leaks but that just made it run lean and I was able to fix them easily. It wasn't blasting off like this bike.
I don't think the slide is stuck open. The carb didn't have a spring in it when I got it but I put one in and it is pretty strong.

What shape is the intake manifold (rubber piece that connects engine to carb) in? Is it all cracked up?

IMO it isn't bad. Hairline cracks here and there but nothing bad. I had a cracked boot on my old bike and just put some sealant on it and it was good as new. I may try that here too.

You know, I have an old PWK carb sitting around. It isn't in the best shape (slide is rough) but it ran fine on my bike when I pulled it. We might be able to work out an affordable deal on it if you decide to go that way.

We'll see. I really should be able to make this carb work, I just need to figure out exactly how much work/money it is going to take to do that.

[fuzzy]

Wouldn't worry about the dents in the pipe. Ditch that VM32 pronto. Lord know how it's jetted, and it's not worth trying to sort out....Don't hurt the motor in the process.

[KarlP]

I'd take SS109 up on his offer of a carb, hopefully it comes with the cap intact and that little throttle tube.

I broke one of those tubes and found out it is not replaceable; you have to buy the whole top cap

Just to be sure on interchangeability measure your intake and outlet outside diameters on your existing carb.

[Thrahl]

I took the carb off and measured it. It is a 32mm. It has the stock pilot jet and a much larger main jet.
Also while I was in there, I realized that I had installed the floats the wrong way when I first inspected it.
Got everything back installed correctly and hooked it all back up.

I was able to get the bike started but would not idle without me holding the throttle open a decent amount, even with the idle screw all the way in.
It would still go full throttle sometimes but I was expecting it and could catch it really quick.

It seemed like every time it would floor it, it would not want to start after that. After adding more gas to the carb (the tank is off I have a little squeeze bottle to give it more gas) it would start right up and be fine (aside from just running like ****).
Maybe it would run out of gas, lean out, and go crazy? Idk but that doesn't seem likely to me.
It also was burning through gas like crazy. I only had it idling for a total of like 2 minutes and went through probably 16 oz of gas.

Honestly, like you guys have been saying this whole time , this carb just doesn't look like it is going to be worth it.
Does this forum have a PM feature? (maybe I have too low of a post count) I'd like to talk about that carb more SS109

EDIT: I also just read this while doing a little research.

A bike will only scream when going lean if the jetting is wrong.
If you are jetted rich on the lowend you need to crank the idle speed screw up to get to a resonable idle rpm. As the air/fuel leans out it gets closer to the ideal ratio and the rpm begins to climb, because you have the idle screw set too high!
When setting the air screw you usually set the idle speed screw to one point, then adjust the air screw to the point where the bike idles the highest (or just slightly rich of there depending on throttle response). This means if the bike runs richer/leaner than that the rpm will drop, not race sky high.

Sounds like exactly what is happening to me and makes sense too.

[david]

Yes, when a 2 stroke runs out of fuel the engine will start to rev up right before it dies.

[SS109]

I'd take SS109 up on his offer of a carb, hopefully it comes with the cap intact and that little throttle tube.

I broke one of those tubes and found out it is not replaceable; you have to buy the whole top cap

Just to be sure on interchangeability measure your intake and outlet outside diameters on your existing carb.

Unfortunately it wouldn't come with the little tube on top (it will have the cap) as I need it for my new RB carb. I thought I remember reading about someone actually making one a while back that worked just as good as the factory one. It was either here, TT, or DirtRider.

Thrahl, you have to be a supporting member to use PM's here. If you are still interested you can contact me at kellylee 1970 @ gmail.com (just remove the spaces!)

[Thrahl]

did you get my email SS109?

[SS109]

Email received and replied to!

[fuzzy]

It has the stock pilot jet and a much larger main jet

Stock for what? The bike didn't come with that carb.

Definitely have a (bad) lean condition. You could have a boot leak....carb could be leaking internally...etc. Def take up SS on his offer....If not eye up ebay for a 35mm OEM KDX PWK carb. They are common.

[Thrahl]

Stock for what? The bike didn't come with that carb.

Stock for that carb off the shelf. The thing is, the carb was designed for either 2 stroke or 4 stroke. Mine is the 2 stroke version but it is very confusing to find information on.
Regardless, it won't be a problem anymore.

Definitely have a (bad) lean condition. You could have a boot leak....carb could be leaking internally...etc. Def take up SS on his offer....If not eye up ebay for a 35mm OEM KDX PWK carb. They are common.

SS cut me a good deal on the carb so I took it. I figure with the vast amounts of unknowns on this bike, I might as well clear up one big issue and just get going on the right foot.
Hopefully when that comes in it will atleast get started and running halfway decently.
Since SS is in Arizona and I am in Florida I'm sure a rejet will be in order but at least I will be closer than with the random Mikuni.

I'll try and unload the Mikuni on eBay for whatever I can get for it.

[Thrahl]

Well I took the reed box off today to check the reeds and take a look at the piston/cylinder.

It looks like someone used sealant or something on the carb side. I'm not sure what is going on here.


Also, one of the reeds has a small chip in the corner so even if the box is usable, new reeds are in order.


I don't really know anything about piston/cylinder condition so I will just post and you all tell me what you think



In the second picture there is a lot of discoloration on the sides. The piston itself if butter smooth to the touch, even on the discolored areas.

If you all think it is something to be worried about then I will go ahead and pull everything off and get a real look and see exactly what is going on.

[david]

Definitely needs a new reed cage and valve. I can see the corner of one broken off. Don't know what or why all that goop is in there. Looks kinda like melted plastic but could also just be discolored clear silicone. Stupid previous owner whatever it is.