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My kids got our family into riding ATV's the last few years, my background in the old days (way back) was on two wheels (red thumpers) so I decided to get a trail bike.
Spent some time looking around and chose a E2 KDX, it was cheap, a great trail bike, and I also thought would make a great shuttle bike for our raft trips.
The good; mostly stock, looks lightly used, plated in Montana, plastic OK, rubber good, Barkbusters, flywheel weight?
The bad; no compression at all, so I am looking to do a full engine rebuild, I want this bike done right.
I want it re-plated when I'm done so it lasts, who out there does the top end re-plate, I'm near Billings MT, and what is the average cost for a top end job, piston/bore/re-plate/hone ?
I was thinking about an Eric Gore 220 job but that would more than double the price of the machine as it sits now, it would be nice but truth is I'm not sure I want to go that fast anyway.
I'm a fair machinist with a good shop and already have some of the new parts for this job.
I know I'm going to need to re-do the forks before I'm done, but for now getting her running is what's needed.
So I'm sure I'll be on here asking all kinds of stupid questions because I've never rebuilt a two stroke motor completely before, just wanted to say hello and introduce myself.

Snapcap

I just bought a top end (including replating) for my E-6, it was just short of $500, including piston and gaskets. The bad news (if that isn't bad enough) you probably need to do all your bearings as well, and other "odds and ends" and the whole rebuild (no bottom end) will run around $7-750...reasonably. You can save some money by finding a plater, I went through a shop, so it was a little more $$. They said it was done "back east" and the plating is suburb. You MUST buy the piston kit and send it with the cylinder.

6 Riders wrote:I just bought a top end (including replating) for my E-6, it was just short of $500, including piston and gaskets. The bad news (if that isn't bad enough) you probably need to do all your bearings as well, and other "odds and ends" and the whole rebuild (no bottom end) will run around $7-750...reasonably. You can save some money by finding a plater, I went through a shop, so it was a little more $$. They said it was done "back east" and the plating is suburb. You MUST buy the piston kit and send it with the cylinder.

So the Forward Motion price ($600) for the 225cc re-bore doesn't look that bad as it comes with piston, gaskets, wristpin bearing etc.. They do a port job and install the power valve also. The top end is ready to go in.
When you say "all your bearings as well" which are you talking about, I always thought splitting the cases pulling the crank and changing the bearings and seals in the cases was considered a "bottom end" rebuild?
Are there other bearings that are normally replaced when you do the "top end"?
Thanks for helping me out, like I said before I have a lot to learn.

Forward Motion is Millenium Tech...THE place to get your cylinder replated IMO. Lots of folks on here have nothing but great reports on their work. That said, they don't do a big bore for the E-models, only the Hs. Overboring on the E series is a little trickier because it involves modifying the exhaust valve. I'd get the cylinder off first and see what the cause of your compression issue is. Cylinder may be in fine shape and just require new piston/rings. On the plus side, once it's up and running it's a great shuttle bike, and a great bike for weaning the kids off 4 wheels

snapcap wrote: So the Forward Motion price ($600) for the 225cc re-bore doesn't look that bad as it comes with piston, gaskets, wrist pin bearing etc.. They do a port job and install the power valve also. The top end is ready to go in.
When you say "all your bearings as well" which are you talking about, I always thought splitting the cases pulling the crank and changing the bearings and seals in the cases was considered a "bottom end" rebuild?
Are there other bearings that are normally replaced when you do the "top end"?
Thanks for helping me out, like I said before I have a lot to learn.

Sorry, I was talking about suspension and wheel bearings. They are "usually" bad on these old KDX's and I found mine where trashed, so that added a hundred+ to my rebuild. I also bought new cylinder studs as mine looked pretty corroded, and new nuts for the head and cylinder since they where a whopping .12 each. Oh, and since my swing arm bearings where bad, I'm replacing the bolt that holds the frame/swing arm/motor together, that alone was $30. What the hell, I don't want to take the whole bike apart again for a while.
But basically, the top end kit, piston wrist pin, c-clips for the piston and piston bearing, along with the plating was $425. I didn't take out the center power valve, so I probably paid some labor for that.
I'm sure I could have gotten it done cheaper If I sourced everything myself, but it was my friends shop and I don't mind keeping them in business.
Also, don't forget to remove the head studs, the plater will charge you to take them out and then probably loose them.

OK thanks, I have both wheel kits, rear shock linkage and swing arm bearing kits right now in a box in my shop.
I also have a pro-x con rod and a crank bearing kit as well as a bunch of new tools.
I had a KDX Christmas.
Feels like I'm going to need to do something about my steering stem.
I have some work to clear out of my shop but then I'm going to take this thing apart.
Like you, I want to try and do a project once and then enjoy it, thanks for the tip on the studs.
As worn out as this motor seems I had given up hope that I could just replace the piston and go with it, but maybe there's hope for that.
Thanks guys.

snapcap wrote: As worn out as this motor seems I had given up hope that I could just replace the piston and go with it, but maybe there's hope for that.
Thanks guys.

you've got a lot to learn about KDX
their biggest fault is acknowledging when they should call it quits ;)

diymirage wrote:you've got a lot to learn about KDX their biggest fault is acknowledging when they should call it quits ;)

Lol so true...motors running with 60 psi compression, holes in exhausts, pieces of motor rattling around in the innards, etc so many examples...

or as Batesy so eloquently put it:

rbates9 wrote:It still ran because it is a KDX and they just don't know any different. They just run out of habit.