1989 KDX 200 Basket Case Project

[SS109]

I agree 100% with Nick and rbates, if you are in there, replace the bearings and seals!

[Thrahl]

Well I popped the crank out tonight and got a bit of a surprise.

It looks like something went through the bottom end at some point.
I think it's aluminum and I don't think it came from the case or crank so cylinder or piston?

Here are pics of the crank.



There are discolorations around the crank and in the last pic though you can't really see it there is a very small rough spot. You can feel it with your finger.

The other case half has much less damage.


The thing is, the worst spot on the crank (3rd crank pic) is on the left side rather than the more damaged right case side.

What do you guys think?

[Thrahl]

Alright well I did some research last night and this morning and people seemed to say some damage to this area of the crankcase is not a big deal as long as the mating surfaces between the two halves are good and the bearing seats are fine.
But because the metal that is there is not from the case and just sort of stuck on I want to remove it.

So I sanded it down pretty much flush and then buffed out the majority of the scratches with some steel wool to clean everything up.

There is still a small amount stuck on but I don't know if I want to just keep sanding and sanding and maybe mess up the mating surfaces between the halves.

[Julien D]

Probably a broken piston skirt at some time in the past. As long as the crank clears and doesn't rub you'll be fine.

[diymirage]

Probably a broken piston skirt at some time in the past. As long as the crank clears and doesn't rub you'll be fine.

i thought those were exclusive to the 220?

[rbates9]

Probably a broken piston skirt at some time in the past. As long as the crank clears and doesn't rub you'll be fine.

i thought those were exclusive to the 220?

Any piston in any engine can break a skirt. The 220's just had a bad piston design so they were more prone to failure.

[Thrahl]

Ok so I haven't been getting much done lately. Been busy with work and helping friends on their projects. (Just got a buddies 1974 Harley/AMF SX250 running)
I called Langcourt today because it has been 11 business days since they got the cylinder and I haven't heard anything back.
I guess it was ready to ship and everything so that is now on its way back with a new piston.

Also went ahead and ordered the replacement power valve. $35 plus $8 shipping was the cheapest I could find unfortunately.
New crank bearings and seals are on the way as well.

I have sprayed out all remaining bearings with brake cleaner. Should I lube the crank bearings with 2 stroke oil and the tranny bearings with transmission oil?
I am going to blast the cases with soda to try and clean them up while everything is apart.

So hopefully the engine will be done by next week sometime. In the meantime I will be assembling the front end.
I bought new handlebars since the old ones were rusted and bent. They are black and a little higher with less sweep than the stock bars. Should compliment the black frame nicely.

I think the only things left are the air filter, seat cover, and rear fender.
I will get more pics up this weekend most likely.

[SS109]

Should I lube the crank bearings with 2 stroke oil and the tranny bearings with transmission oil?
I am going to blast the cases with soda to try and clean them up while everything is apart.

I lube everything as I assemble it. A drop or two on each bearing of the oil it is normally lubed with, rotate them so it spreads over the whole bearing, and install! BTW, make sure to clean out all your threaded holes immediately after soda blasting. It is the easiest time to get the soda grit out.

[Thrahl]

I was looking at the jets in the carb that you sent me SS109 to see roughly how close I think it will be to what I will need.
It has 45 pilot, 152 main, and an R1171N needle.
I am just a little confused on different needle sizes.
The stock for '89 was R1172N. Going by this conversion chart, the 1171 is richer correct?

I figure the other jets will probably be pretty close to what I am going to need, maybe a touch too lean.
I just want to figure out if I should start the bike with the needle clip at the top so it isn't super rich.

[Julien D]

I would start in the middle clip and go from there. Sounds like a pretty good baseline for most people.

[rbates9]

I just want to figure out if I should start the bike with the needle clip at the top so it isn't super rich.

You are much better off starting too rich than too lean. For longevity the richer you are the better.

[kyledsmith87]

Most manuals recommend greasing bearings before re-fitment. Oil will slide off during the assembly time.

[Thrahl]

Alright got a decent amount done today.
My replacement swingarm bearing came in yesterday and I got it installed.
Nobody ever told me you shouldn't take a torch to aluminum, which it did twice on this swingarm....
Because of that the bearing hole was slightly warped. I had to "hone" it out with sandpaper to get it pretty close to round so I could get the bearing in.
Still took a lot more effort than it should have but it did go in and everything is greased up and moving smooth.

So I was able to install the swingarm, suspension assembly, rear wheel, and rear brake.
Everything went together without too much headache and seems to be working fine.

It is starting to look like a dirt bike again.

Also got a package from Langcourt today
The cylinder looks amazing, couldn't be more pleased. And they have the lowest prices of all of the platers from what I saw so I definitely recommend them.

So tasty even my dog wants a bite.



They included a little note saying there was a small amount of pitting but that it won't affect performance or longevity.

Those tiny little white dots are what they were talking about. You can barely see them with the eye.

You can look back at my the old pics of the cylinder and that is exactly how it left my house. Greasy, scratched, and lots of carbon. Came back like this. Great work on their part.

I also ordered a Pro-X piston kit through them as it was cheaper than anywhere else.

There is an arrow on one side and an A on the other. I assume the A is the piston size but does the arrow point to the exhaust side/front of bike when installed?
Also, I assume I don't need to clean off the sharpie on the dome right?

So now I am just waiting on my power valve from RonAyer (still hasn't shipped yet), my crank bearing kit, and my FMF silencer.

Also a nice little surprise for me. That front master cylinder I bought off a guy on Craigslist for $20 is actually worth about $90. Sooooo that is on eBay lol.
I will sell that and buy myself another cheap one, this time with a built in reservoir.

[Julien D]

Nice work. The arrow points towards the exhaust, yes.

[Thrahl]

Does anyone have a spare oil fill cap they would part with?
I forgot to include it in my OEM parts order and if I placed another order it would cost more to ship it than the part itself.

Mine looks like it was melted or something.

[david]

My local Kawi dealer didn't have the oil fill cap in stock, but it looked like one out of a Honda. Took it to the local Honda dealer and they had one. Cost me about $3. Don't tell 'em what it fits, just hand it to them and tell 'em you want one.

[Thrahl]

My local Kawi dealer didn't have the oil fill cap in stock, but it looked like one out of a Honda. Took it to the local Honda dealer and they had one. Cost me about $3. Don't tell 'em what it fits, just hand it to them and tell 'em you want one.

That's good to know. I was going to maybe stop by a few lawnmower/small engine shops near my house and see if they have anything.

The Kawi/Yamaha dealership is just down the road but the Honda one is a little bit of a drive. I will just have to see what I can get.
I just want to grab something quick. Don't want to hold back the build on something so trivial

EDIT: Also got in my silencer. A few very minor scratches in various places but overall it looks awesome. It will look more at home on this bike than the newer styled silencers I think.
I'll get pics up later on.

[Koko]

Nice work. I'm enjoying watching this build.

[Thrahl]

It's been a while since any updates but I was waiting for parts and then got really busy with other things.
Everything I need for the engine is in, I just need to put it all back together.
I got a new front master cylinder, seat cover, rear fender, and air filter which will all be here soon.
That is pretty much everything. There are still minor things I need to fabricate but I pretty much need to just start getting stuff together.

I just had a few quick questions though.
I was shopping for 2 stroke oil at my local bike shop and was just really confused by all of the choices.
I ended up picking up this Bel-Ray Mineral Oil but after researching maybe it isn't the best?

People were saying mineral oil is the really cheap stuff and isn't good for high revving machines. Others say it is just a little dirtier.
I don't really know. There is too much conflicting information to get a solid conclusion.

Also, I picked up case sealant. The only stuff I could find a my local auto parts store is Permatex Form A Gasket 2.

It resists gas, oil, grease, etc. and is non-hardening. I only found a little info on this stuff but a couple people said it was fine for case sealant.

What do you guys think?

EDIT: I figure I will add a pic of the FMF pipe since I didn't earlier.

Really clean. I think it will look great on there.

[david]

I HATE #2 Permatex. That is the nastiest stuff to get off.