No compression 97 kdx200

[IceCold4x4]

So I just picked up this well used and ABUSED KDX 200 for cheap. Problem is it's got no compression I can easily turn the engine over with a half hearted attempt with my arm. Where should I start to look for causes? This will be my first 2 stroke project I just rebuilt my zrx with a 2mm over bore so I'm not a complete newbie idiot. But wondering if there could be another cause of no compression besides either a holed piston or just plain worn out rings / cylinder.

Picture if the poor bike for pity.

[Jason]

Welcome to the forums. Get a service manual, then check everything. Bikes in that shape and price need attention to everything.

Not sure what you know of bikes, but the cylinder was plated in stock condition. Keep that in mind.

[IceCold4x4]

Sounds like the pita nikasil they used in the zrx1200's how hard is it to sleeve one?

Anyone scanned in a service manual? I guess I've been spoiled by the zrxoa if not.

Oh it'll be gone through from end to end eventually but hearing it pur that stroke tune is first up.

So far what I can tell is the following.

Front caliper and line are missing
Brake lever is bent oddly but looks intentional.
Hole in airfilter and birds nest to be removed.
Needs chain and sprockets (what used bike doesn't lol)
New rear tire.
Replacement of most of the plastics and mounting hardware.
Clean carb.
Clutch seems to not disengage engine even though there is movement and pressure at the arm going into the case (likely some stuck plates from sitting too long.)

And that's just what I know after 24 hrs lol.

Hope to have it running by the 9th for my birthday. So fully diagnosis by tonight order parts and wrench like hell Fri and Sat.

[6 Riders]

I'd start by pulling the exhaust and carb, then looking into the cylinder while turning the engine. Look at the condition of the piston. No doubt that it needs a top end (by looking at condition of the bike). But you have to pull the carb and exhaust to do the top end anyways.
If I were to be bringing that bike back to life, I'd be taking the whole thing apart, every piece, sending the frame and swing arm off to be powder coated and cleaning the rest of the spray paint off myself. I'd plan on sending the top end out to Millennium Technologies for a fresh re-plate and new Weisco piston. Inspect the bottom end (con rod) for bearing play and the clutch for wear. Then rebuilding the suspension and refreshing the brakes with new fluid and pads.

[IceCold4x4]

If I'm going to replate the bore wouldnt that be the time to go big bore? I'm on the heavy side at 260. So more power is always a good thing.

Beleive it or not the suspension is still in great shape from what I can tell no leakage and no pogo when jounced.

I'm going to get it running and mechanically sound and learn the dirt aspect better before I pour money into making it look good. I'm sure I'll drop it quite a few times until my skills get there. Haven't really ridden dirt since I was a kid 20 years ago. Just got back into bikes 3 years ago.

[Jason]

No offense, but I think your time line is a bit ambitious to go from "no service manual, no strong direction and no parts" to riding this weekend.

You already know it has very low compression. Disassembly and replacement of parts is needed.

The not that holds the arm onto the right side power valve arm has LEFT HAND threads!!

[IceCold4x4]

I've seen a few walkthroughs here and on YouTube, heard about that left handed nut but thanks for the heads up. Guess I'll get a service manual on the way and scan it in as a pdf for reference on the go and upload it somewhere for everyone here. Makes searching a breeze too.

I'm sure it's ambitious, but if the bore is in decent shape it should be doable. That's what I'll find out tonight...

[ubareddition]

I got a service manual for a H series kdx. Also have a brand new 1 mm oversized piston once you get that far in the process.

Sent from my SM-N910V using Tapatalk

[IceCold4x4]

I got a service manual for a H series kdx. Also have a brand new 1 mm oversized piston once you get that far in the process.

Sent from my SM-N910V using Tapatalk

I'll keep ya in mind for that. I'm hoping it won't have to touch the bore just yet. But I've made too good of friends with Murphys law for that to be the case...

[bufftester]

I'd also add all new bearings for the rear linkage/swingarm/shock to the list. Most underserviced and abused part of these bikes.

[IceCold4x4]

I'd also add all new bearings for the rear linkage/swingarm/shock to the list. Most underserviced and abused part of these bikes.

Thanks for the tip I'll add it to the growing cardboard list...

[ohgood]

No offense, but I think your time line is a bit ambitious to go from "no service manual, no strong direction and no parts" to riding this weekend.

You already know it has very low compression. Disassembly and replacement of parts is needed.

The not that holds the arm onto the right side power valve arm has LEFT HAND threads!!

don't worry, I'm right around the block from him and ready to tear into it. hell have a fun bike in no time at all. ;-)

holler ! (replied to your post on br)

[Jason]

Please do not post any links to illegally scanned manuals on this site. This site is not wanting tied up in all that. Thanks, and good luck on the bike. You are cheating by having ohgood to help you out.

[IceCold4x4]

Please do not post any links to illegally scanned manuals on this site. This site is not wanting tied up in all that. Thanks, and good luck on the bike. You are cheating by having ohgood to help you out.

Ah ok I won't do that then wasn't thinking about it from that angle purely a convenience thing. I'll take all the help I can get just threw the 10mm into the drywall due to the bolt selection that a previous owner used. Going to have to buy a full set of bolts to replace the already many missing ones only had 1 bolt holding the tank on....

[IceCold4x4]

Well I think that's not looking too good now is it?

But it does have spark so at least the basic electrical system works.

[s10gto]

Looks like someone forgot the premix....That's a perfect cylinder to send in for a 240 kit.

[6 Riders]

Are there even rings left on that thing?

[6 Riders]

Looks like someone forgot the premix....That's a perfect cylinder to send in for a 240 kit.

It's my understanding that the 240 kit is done. Can't get pistons for them anymore

[s10gto]

I believe kustom kraft still shows a listing but possibly not updated.

[Jason]

At least you know where you stand. Keep unbolting.