KDXRIDER.NET

I think I might be a little confused about the reason people go with the 1367 needle. Isn't that needle going to be richer than the stock 1368? Unless I'm incorrectly converting the number the 1368 will be a larger diameter needle which would be leaner than the 1367. Right? I thought the whole purpose of changing the needle was to make everything leaner because the factory jetting/needle was too high. Please someone correct me if I'm wrong.

Also my stock silencer has been modified by the previous owner and it appears to have had the internals from the exit end removed and all the packing is gone. Also exhaust/smoke escapes from the input side where the silencer bolts together. There is a rubber gasket on both the input side and the exit side but that does not seem to keep the exhaust in.

Should I repack the silencer that I have? I tried repacking with home depot pipe insulation only to find that the bike would not hardly run at all ie. would not rev and sounded as if it was stopped up. Maybe I had it to tight.

How can I better seal it up? The previous owner had what looks like HVAC aluminum tape all over it.

Or should I just buy this used one on eBay for $50?
http://cgi.ebay.com/ebaymotors/1993-KAW ... ccessories

The weird thing about the one on eBay is that it looks almost identical to the one that is on my bike now except mine does not say FMF on it. It almost looks like someone took a stock silencer and put an FMF sticker on it.

post a pic of the silencer! ...............if the internals are gone, how did you you repack it??? ........

Here is a picture of the outside of it. I have it back together right now or I would show the insides. I also read where the stock silencer does not have packing but I think they were talking about a 200/220 and I'm guessing the 250 is the same? I guess mine is stock because it says KDX on it and it is a little different from the one listed on eBay.

Well I just went and rode the bike for a couple more hours and I have a few questions and a few comments on the bike.

1. Wow. I'm coming from an XR200 and then an XR250 and holy crap this thing is a beast compared to both of those bikes. I understand that they are completely different bikes. But not really. I didn't ride it any different than I rode the XR's. It never fouled a plug in fact since this is my first 2 storke I'm not even positive what is going to happen when I foul a plug. I'm almost waiting on it to happen but it just doesn't.

2. Are the newer 4 stroke 250's ie. CRF, KXF's as powerful as the KDX250? If not I can't imagine why you wouldn't purchase a KDX250. How about the KDX200/220. How do they compare to the KDX250?

3. Holy crap this thing it fun. I was scared most of the ride but by the end I finally started to feel the bike and kind of know how it was going to respond.

4. Since the compression is a little low at 145 if I put a new piston and rings is it going to be even faster? It's crazy how you can putt around in 2nd and 3rd gear and then through it throttle and the thing just takes off.

5. Why does no one make a bike like this anymore or are the CRF/KXF's this much bike/fun as well?

I should probably stop now because I'm sure if you are reading this then you probably know how much fun this bike actually is.

No, a 250f is not going to be similar in the power department to your 250 two stroke.

Yes, it will probably have a bit more snap with a new top end

KTM, gas gas, and TM are still making 2 stroke trail bikes. That would be the closest thing to date. Yamaha is still producing the 2 stroke yz250 as well, which also makes an excellent trail bike.

kdx200/220 are excellent bikes. They give up some power to the kdx250 but make up for it with agility.

So finally got the piston out. Heres a picture of the piston and cylinder. Piston measured 67.4 and cylinder was 67.23. Probably mismeasured a little What should I do? I'm thinking just new piston butnot positive. This is my first rebuild ever.

Also I cleaned the lips valve but I couldn't get the retaining screw out to completely clean the shaft. Is there a trick to it? I cleaned up everything except the shaft. I was able to clean the valves fairly well in the cylinder and I took the plate out and cleaned it up pretty good.

Wow, that looks pretty rough. It looks like it could use a re-plate. How did you meausre the cylinder? Without a bore gauge it's really difficult to get a measurement down around the port area and below, where it tends to wear first.

I wasn't exactly sure how to measure it.

So how much for a replate? Am I looking at like $200. I really hope it's not that much. What can I do for sure to determine if it needs to be replated? Thanks for all of your help.

http://www.powersealusa.com/prices/
Strip, Plate, Hone $179
Did a good job on my last replate.

Does RBD do work on the 250 as well? Not sure how much more low end I could possibly handle or what i would need But I thought I would at least as if it would be worth it.

I'm sure he would. I also don't think you'll need it though. The kdx250 engine is pretty impressive. You can use a certain year kx250 head gasket if you want more from it. Deal with the re-plate and top end first, worry about power add-ons later.

So I took everything apart again today to get it ready to be sent off. I found that the bottom of the left kips valve is broken off. I don't think I did it and I'm not sure if it even matters all that much because it looks like its been that way. What the heck am I going to do now? Also I had to grind off the corner of the retaining bolt to get the kips slide pin out. Now I still can't get the retaining bolt out. I have no idea why it is so freakin tight.

I'm at a loss now. Also how the heck do I get the cylinder head bolt out to ship it off? or do I need to do that?

This is turning into an expensive nightmare. I should have just rode the bike and left it alone. It was running great just smoking a little.

Well I just found the part on mrcycles and I can get it for $56. It is the right kips valve that does not have the ring around the top. I'm sure I should probably replace it right?

Well after a couple of weeks of having the bike apart I just received my replated cylinder back from Langcourt and it looks amazing. Below are some pictures. I had it welded and replated. I also bought a wiseco piston kit, new needle bearings, a new left side kips valve, new gasket kit. The only thing that I haven't purchased so far is a kx250 head gasket. Actually I bought one but from the looks of it I highly doubt it is the right one. I think this one might be from a newer kx250. But oh well it was only like $14 from eBay.

I can't wait to get everything back together and see how this thing rips. I was already a little scared of it before the top end and now I can't wait to see what it will do.

Before



After


Before



After weld and replate. All nice and clean!

That looks really good. I recently had a piston let go in my 89 200 and it looked like yours before hand. Trust me you 're doing the right thing here even if it costs a bit. I ended up breaking both case halves and trashing the main bearings, not a pretty sight. Make sure they deburred the ports so you don't snag a ring, a couple look sharp!

I kind of thought that a it looked kind of sharp in a couple of places. What would I need to do to deburr it just use some sand paper and knock the corners down a little. I'm not sure how effective sand paper will actually be.

I'm not sure but others here should know. Good Luck