1989 KDX 200 Basket Case Project

[bazzman]

Your absolute best bet on these is to get a machinist to make the guides out of bronze. I am in the UK, but for a few bob I could make some and send them to the states (your bike is starting to lose its cheapness appeal, just like mine did :P), if you keep the bike a while it will pay off.

If you are interested in getting these machined, let me know. I would be interested in a large batch which would then be sold by the set through the site.

No doubt. Even though mine are good I wouldn't mind have at least one spare set around if the cost was reasonable.

i would be interested in a set as well...assuming the cost was reasonable....

[kyledsmith87]

You will have to be patient with me on this one, but I can make a few sets.

What would be handy is if anybody has a new left or right power valve or bush set and can confirm my measurements...




It will still probably be cheaper / easier if you got a batch made in the US. I would be happy to make a few sets but as its going to be "government jobs" at work I can't go into mass production. Plus I'm in the UK so postage may make things interesting... beg.

[scheckaet]

fixed the pic for you

[kyledsmith87]

ta!

[Thrahl]

I just read yesterday (but can't seem to find it now) an article about the exhaust valves tending to break because the guides were too loose and allowed a tiny bit of play which when combined with the weak aluminum snapped teeth. He talked about building up the guide so that it was much tighter and allowed no play in the valve. (he ended up doing that but it failed and the valve broke teeth anyways so his theory was never proven)

Is this what you are proposing these would do?

Also, what is the significance of using bronze? I mean I could do the same thing with aluminum right?

[kyledsmith87]

Aluminium wears very quick, it is the worst bearing material in the world.

Bronze, or alloys including bronze are the best, and most common bearing materials in the world.

The valves will still wear (I made bronze ones for myself, but it is a big job, so until I set up my own workshop I cannot mass produce... hold on to your bike for another 3 years and I will be capable!) but farrrrrrr slower than when in aluminium bushes. Plus if you don't replace the bushes they will knacker any new valves you buy out twice as quick!
Its a shame really because the KIPS system is very efficient, it just engages so damn quick it rips itself to shreds being aluminium :(.

[kyledsmith87]

This is also a case as to why I use a higher pre-mix ratio than most @ 25:1. Poor things need some lubrication!

[Thrahl]

Aluminium wears very quick, it is the worst bearing material in the world.

Bronze, or alloys including bronze are the best, and most common bearing materials in the world.

The valves will still wear (I made bronze ones for myself, but it is a big job, so until I set up my own workshop I cannot mass produce... hold on to your bike for another 3 years and I will be capable!) but farrrrrrr slower than when in aluminium bushes. Plus if you don't replace the bushes they will knacker any new valves you buy out twice as quick!
Its a shame really because the KIPS system is very efficient, it just engages so damn quick it rips itself to shreds being aluminium :(.

Ah, I see now. I guess I never really thought about how the valve is spinning inside of the guide and how that would cause wear.
I was just thinking of how the guide itself can move in its hole.

It seems like many people are interested. Something that small could be shipped very cheaply I would think, even internationally.
I would definitely be interested if they are cheap. Might as well throw them in while everything is apart.

This is also a case as to why I use a higher pre-mix ratio than most @ 25:1. Poor things need some lubrication!

Wouldn't using more oil cause more carbon build up due to less efficient burning?

[Julien D]

What I'm really after are the actual subvalves machined from bronze, steel, or even harder aluminum. Improved bushings may help, but I don't think they will solve the problem. Last time I replaced my valves I put all new bushings in as well. The RH subvalve still broke within 1 year.

[Thrahl]

This thread got a little off topic but I just remembered that I forgot to mention something.
When I drained the oil to inspect the clutch, it was milky which I halfway expected given the sad shape of the water pump seal but what worries me more is that it had a faint smell of gas.

It pains me to even think it but the only way I could be getting a gas smell in the oil is from a bad crank seal right?
There is absolutely no play in either end of the crank so I assume the bearings are still good.

The cases have to be split to replace the seal right?
I don't have a case splitter and very much don't want to buy one. But from what I understand I should be able to make something to do the job.
I know people who have all sorts of pullers, maybe even case splitters so that may help me.

To add to that, the entire crank has to be removed to replace that right side seal too right?

I'm not necessarily opposed to opening up the bottom end and inspecting it. With my luck and the way this bike has been going, half the transmission is going to shot.

On a slightly related note, when the bike is on the stand not running (obviously), it will shift from 1st through 4th and then stop. Is this normal?
It feels like it should do that as my old bike did the same thing but wouldn't go past 2nd.

[Julien D]

When on the stand and shifting, you'll have to roll the rear wheel a bit to engage the current gear before you can shift the rest of the way up. If it stops in forth, rock the rear wheel until you feel it click in and then try to hit 5th.

As far as gas in the oil, yes, leaking RH crank seal is the only way that would happen. If there is no play in the bearings, the seal may sort itself with some use. If you are confident the main bearings are good, I would hold off on splitting until you get it running and see what's what. If you DO need to replace the crank seals, yes, the bottom end must be split and the crank removed.

Sorry about the off-topic rants...

[SS109]

What I'm really after are the actual subvalves machined from bronze, steel, or even harder aluminum. Improved bushings may help, but I don't think they will solve the problem. Last time I replaced my valves I put all new bushings in as well. The RH subvalve still broke within 1 year.

We really need to find someplace to make us some and get a group buy going.

[kyledsmith87]

Wouldn't using more oil cause more carbon build up due to less efficient burning?

You just have to jet accordingly. Also, fully synth oil doesn't burn as well as mineral based. Last time I took my valves apart, they were oily. No dry carbon.

[kyledsmith87]

What I'm really after are the actual subvalves machined from bronze, steel, or even harder aluminum. Improved bushings may help, but I don't think they will solve the problem. Last time I replaced my valves I put all new bushings in as well. The RH subvalve still broke within 1 year.

That is probably down to wear in the lower bushing which is the case. Thankfully the bronze components are tough enough that they don't wear away and begin to lean, even only being supported by the top bush.

I'm going to make a thread discussing this to get it away from here...

[turtle]

Overall though it isn't looking good. I totaled it all up and if I don't find anything else wrong with the bike (doubt it), the entire project is going to total about $1100 to get it 100% again.
When you consider that I have basically bought the cheapest parts available, got lucky with people giving/selling me parts cheap, and done all of the work myself, it really isn't a good deal.
This project is now on a paycheck-to-paycheck timeline too since I have run out of money so updates will be slower probably.

I feel your pain. Even though I have learned a ton about the KDX after buying mine (my first dirt bike) and finding this site, the one thing I tell people I have learned the most is there ain't no such thing as a cheap dirt bike.

[scheckaet]

I feel your pain. Even though I have learned a ton about the KDX after buying mine (my first dirt bike) and finding this site, the one thing I tell people I have learned the most is there ain't no such thing as a cheap dirt bike.

sure beats personal therapy

[david]

I would hold off on splitting until you get it running and see what's what. :

X2
When I bought my 175, it wouldn't run for more than half a second and would take many kicks to get it to do even that. The trans was full of gas, just like yours. I changed the oil and it fired right up. It will fire 3rd kick cold or 1st kick warm now and I have been riding it for over 5yrs with no more problems. I did everything I could think of after getting it running, to prove to myself that it needed crank seals (vacuum test, pressure test, watching for trans fluid useage) but the seals do their job. Just thought I would share my experience.

[Thrahl]

I would hold off on splitting until you get it running and see what's what. :

X2
When I bought my 175, it wouldn't run for more than half a second and would take many kicks to get it to do even that. The trans was full of gas, just like yours. I changed the oil and it fired right up. It will fire 3rd kick cold or 1st kick warm now and I have been riding it for over 5yrs with no more problems. I did everything I could think of after getting it running, to prove to myself that it needed crank seals (vacuum test, pressure test, watching for trans fluid useage) but the seals do their job. Just thought I would share my experience.

That eases my mind a bit. There was only a faint smell, but who knows how long that oil has been in there.

Well I guess I am going to be talking to Langcourt tomorrow and getting the cylinder shipped soon.
Their website says they sell pistons too. Are their prices competitive?
Ebay has std. bore Pro-X for $93 shipped so if they can do that or better then I will definitely pick one up.

Also, I got your package SS109. I must say your packaging was very thourough I don't know if you could have stuffed any more bubble wrap/peanuts in there with a press.
The carb looks great though, a little sticky in the middle like you said but I will try to clean it up a bit. Should be fine either way.
The reedbox looks great too. Quick question though. My old box has little metal pieces on top of the reeds, I assume so they don't open too far.
Do these need to be swapped over to the new box?

[Julien D]

Boyesen reeds do not need the factory stops. You should be good to go!

[SS109]

Also, I got your package SS109. I must say your packaging was very thourough I don't know if you could have stuffed any more bubble wrap/peanuts in there with a press.
The carb looks great though, a little sticky in the middle like you said but I will try to clean it up a bit. Should be fine either way.
The reedbox looks great too. Quick question though. My old box has little metal pieces on top of the reeds, I assume so they don't open too far.
Do these need to be swapped over to the new box?

Glad you got it safe and sound. I don't like parts getting messed up in shipping so I can go a little overboard sometimes when packing things up. No need to swap them over. Just run the reed cage just like it is. Well, after cleaning it up a bit that is!