1992 KDX200 Rebuild

[bigdhusker]

I've been on a quest for a two stroke trail bike and ended up choosing an E series KDX. I located a decent, complete running bike for $700 to start my build. I have owned a KX and a KLX300 in the past, but this is my first foray into the world of KDX's. I do have a few questions and I'm sure more will arise as I progress through the build. I've started to tear the bike down and have found some oil in the stator case cover. This has prompted me to go ahead and completely rebuild the motor from the bottom up.

A) Pro X has three piston sizes (65.94mm, 65.95mm and 65.96mm). I'm assuming all KDX200's have the same bore size, what is the point of the minute difference in piston diameter available?
B) Is it okay to run a flex-hone through the plated cylinder?
C) There are no crank assemblies available--what is the best option for having a crank rebuilt?
D) Are there any front hub assemblies that swap into the 1993-94 forks and eliminate the speedometer housing on the right side of the hub?

I completed some searches and couldn't locate specific info pertaining to my questions, plus I'm also hoping for some general guidance, opinions, and potential known pitfalls I might run into through this process. TIA

[david]

Cant see the pics.

The stock piston will have a letter stamped on the top of it (A,B, or C). I believe the three sizes that ProX offer correlate to those letters. This is typical of Japanese engine assembly and why their motors in general last longer than ours did.

I think you need a diamond hone to cut into the plating. If yours is in good shape (no gouges, or worn through spots) then you can just replace the rings and piston if needed. If your piston looks good then just leave it alone.

I think just about any place that rebuilds 2 stroke cranks can rebuild it. Hot Rods has a replacement rod for it.

No need to eliminate the odometer drive assembly, you can just cap off the cable connection to keep the gunk out. Or, source the rest of the system and put it back to stock.

You will want to look at the two side exhaust valves as they have a habit of stripping out and limiting power output (they are aluminum). You can get steel replacements from BDK in England. Very nice pieces and we are thankful that he stepped up and made them for us. http://www.bdkraceeng.co.uk/tc/

[lucy]

The stock piston will have a letter stamped on the top of it (A,B, or C). I believe the three sizes that ProX offer correlate to those letters. This is typical of Japanese engine assembly and why their motors in general last longer than ours did.

Does this apply to the H series KDX 220 as well?

[david]

It applies to factory assembly. Not all piston companies offer the incremental sizes and I don't think ProX makes a piston for the 220.

[ScruffyDroid]

The stock piston will have a letter stamped on the top of it (A,B, or C). I believe the three sizes that ProX offer correlate to those letters. This is typical of Japanese engine assembly and why their motors in general last longer than ours did.

Does this apply to the H series KDX 220 as well?

Wossner make replacement forged pistons for the 220 and they also have the 3 different diameters. You need to mic your bore to determine which you need.

You cannot/should not run ANY hone through a plated bore.

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