1993 Rebuild....and Intro

[brucifer]

Hey guys, new KX500 owner here. I've been riding since I was 4 years old--mainly four-strokes with the occasional two-stroke thrown in. I'm now 48.
I just sold an '84 CR500 so I'm not a noob to 500cc two-strokes but I am to the mighty KX500.

I had posted a wanted ad on CL for a dirt bike project and was offered this bike. The PO had purchased it from a neighbor who pretty much didn't know the meaning of the word maintenance. The gentleman I purchased it from gave me a list of everything he did to it and what he thought needed attention. The bike had not run since the PO bought it from his neighbor but I was assured it did run.
When it was delivered to me, I checked it over and discovered it had decent compression but something felt "loose" when I kicked it over. I got it on compression and grabbed the kickstarter with my hand and kinda moved it against compression and relaxed, against compression, relaxed a few times and could feel play and could hear a muted kind of a "clank" in the top end. The first thing I thought of was the wrist pin/bearing.
I put fresh gas in to see if it would actually fire--and it did. Unfortunately it was rattling like heck.

Soooooo....time to pull the top end and have a look at the damage. I figured I'd document the process here and share what I found. I welcome any input you guys would like to give during this process.

Here's the bike.




Thanks.

Bruce

[sandblaster]

Hey Bruce, welcome to the best Kawi forum on the web.
There is more info, combined knowledge, and people who are willing to share then any other site out there.
Pop the top off that thing and lets have a look.
And while you have the top off, take a close look at the crank and lets see what all you may need.
Looks like you have a nice clean bike to start with.

[Foxx4Beaver]

welcome brucifer....nice clean lookin 93.
do you plan on keeping it for a while?

[brucifer]

Thanks for the warm welcome fellas. 

The bike looks better in the pics but it actually is in pretty decent condition as far as rust/corrosion etc. I bought some UFO plastics to replace the faded stuff currently on it.
I do plan on keeping it--as long as we get along. 

[brucifer]

Okay, I removed the top end and it's worse than I imagined. 

With the head removed, it was revealed heavy scoring on the cylinder.


When I removed the cylinder, the source of the rattle presented itself--the rod big end. It has about 1/4 inch or better up and down play and it's trying to lock up as well.


The piston.


The intake manifold is all cracked.


Are these reeds stock?


When I was removing the cylinder, some leftover coolant poured directly into the crankcase so......
W

[Foxx4Beaver]

yup, that's a bummer!...with the crank being that shot, you can only assume the rest of the motor is screaming for some TLC.
Since you said you plan on keeping it...might as well do it right and drop $1500 right off the top, and replace all the bearings/seals, new OEM crank, re-plate cylinder and top-end...and then any clutch or tranny issues that need attention will cost more...but it'll be worth it!

[sandblaster]

+1...
I know it's a bummer to see your engine like this but it's all rebuildable.
Could you post some pics of the bottom of the cylinder and also looking into the intake area?

[brucifer]

Yeah guys, I'm gonna go completely through it. I'm a sucker for orphaned and abused bikes. I take joy in bringing them back to health--and losing money in the process. 
All kidding aside, I really do enjoy this. It's relaxing to me and quite satisfying to experience the end result.

I just went through this with a plated '95 XR600. I did a frame up resto-mod and sunk way more money into it than it will ever be worth. lol. But in the end it was worth it to me and I'm very happy with the result.

Here's a kinda fuzzy pic of it.


And a not so fuzzy pic.


sandblaster-I'll get some pics of the cylinder in the next day or two.

[sandblaster]

Sweet.
Thanks!

[brucifer]

+1...
I know it's a bummer to see your engine like this but it's all rebuildable.
Could you post some pics of the bottom of the cylinder and also looking into the intake area?

Here's some pics.

[staffylad]

Hey Bruce, welcome to the best Kawi forum on the web.
There is more info, combined knowledge, and people who are willing to share then any other site out there.
Pop the top off that thing and lets have a look.
And while you have the top off, take a close look at the crank and lets see what all you may need.
Looks like you have a nice clean bike to start with.

I just luv those blue forks like I need some

[sandblaster]

Appears to be completely stock...
A little time with a dremel goes a long way 

[Foxx4Beaver]

thought my eyes were playin tricks on me...almost looks sleeved.

[DoldGuy]

thought my eyes were playin tricks on me...almost looks sleeved.

That is sleeved.

From the pics of the piston & cylinder, I think the head gasket was leaking (HATE those fiber head gaskets) & washed down the cylinder (no oil between piston/cylinder) as the scuffing in the cylinder is at the exhaust port (just my $.02).

I have seen a sleeved cylinder, with no matching of the ports, and still can not understand how it runs so well, as there has to be at least 2mm mismatch in the ports, but it runs very well.

Good thing with the sleeved cylinder it can be bored for not to much monies  , add a piston kit, rod kit, crank bearings / seals & a good set of gaskets will hopefully get you riding the K5  , but I would positively make sure BOTH cylinder & head surfaces are totally flat. Had a friend with a K5 that was sleeved, kept having head gasket issues & it was just a very small area of the sleeve raised causing the problem.

DoldGuy

[Foxx4Beaver]

thought my eyes were playin tricks on me...almost looks sleeved.

That is sleeved.

I know, I was being sarcastic...you can clearly see the difference in color.