New to me 89 KDX200. Another rebuild story...

[skyriver]

Hi guys,
Let me start by saying "Thanks"! I've already learned a bunch from lurking here. I first found the site when I finally decided on the KDX200 as my 14 year old's next trail bike. He's been on thumpers his whole life, but is finally at a stage where he would like a little more zip. And we wanted something easy to kick. He rode my dad's KLX300 and loved it except when he had to restart it. It starts well when cold, but not so fun when hot. As a KTM 300 rider I was thrilled to hear him say he wanted to try a 2-smoker.
So the hunt began for something under $800. Tough task for bikes that aren't trashed. Well, I ended up buying a project for $500. Ha!
Here is our 89 KDX200 with an 88 KX125 thrown in the deal as the advertised "parts bike."
The KDX is decent, but has been neglected. The KX has REALLY been neglected. I'm still at the tear down state. So far, carb is pretty clean, reeds look great, but the flywheel (and it may have a weight) is rusty. So headed to the bike shop soon for a puller. I've already put the Protapers that were on the KX onto the KDX. So far the "parts bike" idea is working!
Oh, speaking of that, the KDX has the KX swingarm on it. Appreciate if anyone knows if that is a good option or not. The KDX has a 18" tire so good there. Needs the brake installed though. Should be an adventure...

[Fletch]

Nice to see another 89(and another e-series as well). There are a few of us 89ers around. Welcome!

[skyriver]

Update:
Took the KDX down to the frame yesterday. Motor looks great. It actually had decent looking gear oil in it and the piston looks great. Only issue besides rusty flywheel (knocked most off, not too worried about it) is the oil plug hole is stripped. PO had used the stock plug wrapped with thread tape so it wouldn't leak too bad. I'm sure I can tap it or do something there. Anything that has worked for you guys I'd love to hear it. I'm anxious to throw the motor back in the frame, but I know I need to deal with that issue first.
Spent 3 hours today cleaning everything. Pressure washed all parts that can handle it. She's cleaning up pretty nice. My kid thinks the KX front fender looks best (I agree) so he bolted that up. I removed the KX swingarm. I'm going to go with the KDX swingarm since we mostly trail ride and he'll want the kickstand. The KDX swingarm probably weighs only a pound or so more than the KX so not a huge weight saver with the KX. I assume that is why the PO put it on there.
Going to need new fluids, new bearings, new chain, new sprockets and new tubes. Already got a 45 pilot, 155 main and will get the 1173N needle since it has a FMF Fatty (no dents!) on it. Can't wait to fire her up, but may not have much time until Thursday.
What's the trick with the top clamp so the bars are not so far back? Looks very strange especially being a tall (6'4") rider. My kid is 5'11" and still growing so it looks like even with the risers and Protapers they may be too far into the cockpit for him. He already sits too much anyway! I assume there are some top clamps that that are a straight replacement that work better. Would love to hear some suggestions.
Thanks!

[Julien D]

I think you can use the top clamp off a 95+ to get rid of that funky angled setup.

[Fletch]

I think you can use the top clamp off a 95+ to get rid of that funky angled setup.

Yep that's a fact. KdxQuebec had this set-up

[skyriver]

Sweet, good to know there's an easy fix. We'll do that down the line. Right now we have to get this tap-insert done on the oil drain so I can slap the motor back in the frame, fill with liquids and fire this bad boy up.

[Fletch]

I went through a helicoil setup with that drain plug and it was finnicky. The little tab from the helicoil broke off and went flying into the bottom end and there was aluminum chunks in there from the drilling process. I had to flush the bottom through the clutch cover with solvent and make a magnetic drain plug to get the helicoil piece out! It was hell but I got all the bits out.

Be careful is all I'm saying

[skyriver]

I was successful fixing the stripped oil pan using a 25/64 drill bit and 7/16-20 tap as kdxquebec described on DirtRider.net. I think he's on here too. I've seen his videos on YouTube and pics on bikepics.com. He's everywhere! Ha!
Yeah, Fletch, I definitely have aluminum shavings in the case now. I'm just going to flush with oil a few times. The 7/16 stainless bolt I'm using is a bit long so I have a 1/8" nylon washer that I think will work nicely to keep it snug without too much stress on the aluminum threads and hopefully help with leaks. We'll see.
I was just happy the drill and tap went well. I don't believe any big chunks broke off and definitely no steel in there. Most of the shavings from drilling were grabbed by the grease I put on the bit. Worked pretty slick actually. Any shavings in there now are from the tapping. I'll try to cleanup with greased qtips or something. I've had good luck with that on other projects.
Motor is back in the frame! Plan on putting the motor back together, re-fill with fluids and trying to fire her before moving forward with new swingarm bearings, wheel bearings, new tubes, new gaskets here and there, new chain, counter sprocket and probably a new clutch cable.
And I have to see if the rear brake even works! I'm pretty confident she'll run, but want to make sure before we spend more $$.

If anyone needs any 1988 KX125 parts let me know.

[skyriver]

Worked on the KDX a lot this week. Got it mostly back together and fluids installed. Just waiting on a new air filter before I try to fire her up. Ordered swingarm bearing kit, clutch cable, air filter, chain and a counter sprocket (12) from RockyMtn. Half inspected the muffler. I couldn't ge the other half apart! I got it hot and banged on it pretty good and decided it wasn't worth the effort (or damage) so put it back together. I know air gets through so worse case it's a bit loud. It's a 82db silencer though so it should still be fairly quiet. We'll see. Inspected tires, looks like both tubes have bad valves and probably need replaced anyway.
Still considering using the KX swingarm. It is lighter, has nicer chain tensioning, is in better shape and I need a rear brake either way. Also, the KDX swingarm is possibly damaged from bearing abuse. If the KX rear brake functions (probably not) or I can find one on ebay then I'm leaning towards the KX swingarm.
Anyway, she's cleaning up fairly well. I used some shower scrub on the plastic today (not the seat! ) so she's looking better anyway.
Oh, and had to go back to the stock bars since the Protapers were hitting the gas cap because of the funky top clamp. Who was the idiot that designed that? Or better yet, the guy that approved it!

[Julien D]

Man, that is looking GOOD.

The snail adjusters on your KDX are bomb. I wouldn't bother with changing the swingarm. Every bike should have snail adjusters. The double nut and bolt method sucks, lol.

[skyriver]

Thanks man. Yeah, the snails are good, but I'm used to messing with tensioners on my KTM and on my 11 yr old's BMX racer. And our TTR125LE has snails that I think aren't quite right. With them both set to the same value the wheel seems a bit off. I guess something could be bent. I know I've ridden it too hard a couple times.
I'll see how the swingarm cleans up. If I can get the nasty ground in remnants of the old bearings out of the KDX swingarm then I'll use it. I would prefer it simply for the kick stand option. I don't have a kick stand, but I'm sure I can ebay one eventually.

[skyriver]

Installed a new air filter, filled the tank with 1/2 gallon of 92 octane mixed almost to 32:1 with DuMonde Tech and went for it. Started on 2nd kick!! Big relief. The petcock is leaking as I could see some gas spill out when I moved it outside to kick it over. The gas was in the off position, but knowing the bowl was probably full I just kicked it. 2nd kick! Dirt bikes are so tough it's unbelievable. It actually died after I didn't give it any throttle since I didn't want to flood it. So then it restarted in one kick!
Idle was real high, maybe because the bowl was full? Turned it down quite a bit and still higher idle than my KTM300. It's not so high as to be annoying like the kids do with their 250f's in the woods.
After a tiny bit of smoke for only about a minute it ran really clean. Crisp as can be. Wasn't any louder than my KTM which blew 93 db about 6 rides ago. Anyway, really excited to have a known runner. Kill switch even works!
Jetting:
550 ft elev, 55 degrees
155 Main
45 Pilot
1172N-4
air screw- 1 turn out
FMF Fatty pipe with stock silencer

Now the nasty swingarm bearing removal. Probably need to buy some threaded rod as banging away with the hammer just gives me a headache. Might have to get a torch too. All that's left is swingarm bearings, rear wheel bearings, and some new inner tubes and I'll take it for an easy ride. Still have to get the rear brake working. Can't wait to ride it! Once the rear brake is good I plan on riding it pretty hard, but close to the truck before letting my kid on it. This will be his first 2-stroke so want to make sure there's no surprises. No sticking throttle, no weird stalling and . He's coming off a very predictable TTR125LE and KLX300. In preparation I've installed a 12 sprocket so will be 12/47. Nice and low. If it's too snappy I'll put a 13 on there. I think he'll like the 12 though since he's coming off the thumpers. Should be a great spare buddy bike as well.

[Fletch]

Awesome thread. Good Job, Your boy's going to love that bike. It has plenty of torque for a woods bike and is really fun in the tight stuff. The 13/47 combo (the stock combo BTW) is what I run and it seems very good for the tech knarly stuff I ride here. It'll be a bit more torquey with the 13t.
Good work.

[kdxquebec]

Hey! Nice bike. To restore my kdx to bare frame few years ago was one the my best desision Still enjoy my ride a lot! An other good decision was too keep those plush stock forks with xr400 springs and 5w oil. God I love 'em on nasty stuff.

Skyriver, look back I'm here

[Julien D]

Hey! Nice bike. To restore my kdx to bare frame few years ago was one the my best desision Still enjoy my ride a lot! An other good decision was too keep those plush stock forks with xr400 springs and 5w oil. God I love 'em on nasty stuff.

Skyriver, look back I'm here

Good point on the forks. On our nastiest and steepest single tracks I do miss the stock forks. For anything over 25mph the new forks are way safer.

Sent from my ADR6350 using Tapatalk 2

[skyriver]

Thanks for the pointers guys. XR400 springs should be plentiful. Made a big score on ebay last night. Got a complete rear brake system from a 94 for $28 + $6 shipping! Both of my existing calipers were open to the air and rain for quite some time. The KX one is junk for sure. The KDX one might be ok with some work, but the slider bracket was broken and the only brake line I have is from the KX and I'm pretty sure there's a village of bugs living in it.
So now I'm committed to the KDX swing. Have to find a kick stand. Might have a chance to changeout bearings tonight. Petcock repair kit is in the mail so I can fix that soon.
Can't wait to get this thing on the trail.

[TrophyHunter]

Interesting thread. Good to get some ideas of things to look for when I get to 'em.

[kdxquebec]

H series rear caliper/bracket combo and kickstand is a bolt on replacement for E series.

Nice deal on your ebay set

[skyriver]

Swingarm is on the bike with new bearings! Couldn't find the threaded rod I used last time I pressed bearings so had to use a bicycle axle. Worked well, but it's too short to be of any use for the rear wheel. I have one stuck pretty good in there. It appears the hub is like my KTM in that just one side has a clip so I know which way it needs to go, but it's being stubborn. That will have to wait until Monday most likely. Oh well, feels good to get the swingarm back on there.
Yes kdxquebec, I was quite pleased with the ebay purchase. One of the best I've had in a while. I guess I better wait and see if it works before I get too happy.

So I have the stock (mechanical) odometer hub on the front wheel. Thankfully, the PO put a plug in it so it's not full of dirt and rust. You guys think it's worth finding a stock cable and odo or should I just go the Trail Tech route? My kid has done a beginner enduro and may do more in the future. It would be nice to have some sort of odo. Would love to hear any opinions. Do XR odometers fit? That can come later.

[skyriver]

MEMO: 1988 KX125 rear axle is too short for KDX200 swingarm!
I didn't even think about this until I put the rear wheel (with new bearings & seals) on and the KX axle barely made it through to the other side. Oh well, I needed another snail adjuster and found a 94 KDX200 axle, nuts and 2 snail adjusters for $23 total on ebay. The wait continues...