KDXRIDER.NET

I recently bought a 2004 KDX 220R. You guys already know this, but what a fantastic bike. I was running through the woods like I have never done before. I am coming off a KLX-250S, which is a pretty heavy bike. I really like the throttle response on this 2 stroke (my first.) I read many posts prior to my purchase, and felt comfortable making the leap into the 2 stroke arena. It took a little getting used to at first. Not so much the power, but not having engine braking. I didn't realize how much I depended on the breaking effect of a 4 stroke. But, now after 5 or 6 hours of riding, I feel more comfortable and really like the bike.

The bike was really clean when I bought it, and completely stock, right down to the plastic handguards. It may have the original tires as well, but I'm not sure. There is very little wear on the bike. The usual frame rub areas are present and they don't appear to be overly worn. I checked the carb and everything is still stock. My first compression check gave me a reading of 130 psi on a warm engine.

I'm a 40 year old, C rider, btw.

1st Question
I haven't checked the piston, but I have to presume it's stock since everything else on the bike is. So, here is my first question. Should I bite the bullet and do a top end???? The bike is running great, doesn't smoke excessively. I had a mechanic check it out and he agreed. I don't get any spooge out of the stock muffler after running through the woods. I did get some early on when I ran it in my garage. I'm apprehensive to do a top end because the bike is running so well. What would you guys do?????

2nd Question
I was looking at the header and frame clearence and trying to decide on a skid plate. The header is actually lower than the frame. Do you guys run into issues with the header when crossing logs, etc.???? What skid plate should I install??? Do you have spare headers on hand, just in case?

I've got more, but I'll wait on these answers first.

Thanks,

Jon

I am a 43 year old C rider, so I am right with you. I am trying, but may never make it to B at this point.

The stock CAST 220 piston has a reputation for breaking and destroying the motor. Lots of cases have been documented on the forum. If you think it may be stock, a Wiseco Forged piston would be a good investment, and far cheaper than a total rebuild. You could also just take the head cap off and check for Wiseco part numbers on top of the piston. It is an easy rebuild, and you should clean the exhaust valve periodically anyway. Just make sure to hold the kips shaft with a wrench when removing and tightening the nut, or you will break the governor inside the case. Or remove the clutch side cover and the shaft comes with it without removing the nut.

gsa102 wrote: You could also just take the head cap off and check for Wiseco part numbers on top of the piston.

Is a gasket change necessary when doing this?

jworth94 wrote:

gsa102 wrote: You could also just take the head cap off and check for Wiseco part numbers on top of the piston.

Is a gasket change necessary when doing this?

If you pull the head, you should replace the head gasket. They are crush type single use gaskets. If you take the jug loose at the bottom, you can slide the whole thing off with the head in place. Many times the jug will come off without damaging the base gasket. Then you can inspect everything, and if all looks good you can put it back together without needing any gaskets replaced. Some people will tell you if you remove the jug, you should replace the rings at a minimum. Seeing as how you just got the bike, it's a good idea to tear it down and check the condition of the top end and crank anyway.

I would most definitely check to see if it has the stock piston. If it does, replace it immediately! I know some have run their KDX's for years on the stock 220 piston with no problems. However, there have been way too many horror stories of when the piston skirt lets loose and you end up having to do a complete rebuild (top and bottom ends!) or destroying the engine completely! It just isn't worth the risk for how cheap and easy it is to replace it. All you need is a piston (normally comes with new small end bearing and rings), top end gasket set, and a little bit of time.

1. Definitely replace the piston if it is a stock unit. I've bought two basket cases from people whose piston skirts have shattered. One was a real low hour bike. On the other hand, my first KDX220 was well used and still had the stock piston in it. If it does go, it does a lot of damage and is an expensive fix. Replacement is good insurance.
A helpful note if you pull the cylinder: the nut on the top of the KIPS actuator shaft is left-handed threads, so while you are supporting the shaft go "righty-loosey" on that nut. I recommend you buy or download a manual. You will want it when you put the KIPS gears back together.
2. I question the need for a skid plate on the KDX. The frame and extensions do a pretty good job and keep it easy to clean up. The high ground clearance and short wheelbase help limit the high centers. Skid plates are sometimes more trouble than they are worth (although I have one on my hybrid). I would recommend a pipe guard though.

The skidplates on all three of my KDX's have dents and gouges on the bottom that make me glad they are there to protect the engine. Just say'n.

Well, I have a stock piston. Pretty much what I thought. You can't really see it in the pictures, but there is clearly an "A" stamped on the top backside of piston.

Pictures aren't great, but you get the idea.

Is there anything else you guys can glean from the pictures???

Also, the gasket had some clear spray-on type (I guess) gasket stuff on it. Does the new gasket come coated with that stuff or do I need to buy some??

Thanks,

Jon

http://s665.photobucket.com/albums/vv17 ... G_0165.jpg

http://s665.photobucket.com/albums/vv17 ... G_0164.jpg

Well, here it is. I debated on taking the stock piston out because the bike was running great. It's a good thing I pulled the jug! Thanks to all you suggested I inspect/replace the piston. Sage advice! The first crack is obvious. The second one is smaller and almost looks like a piece of lint... it isn't. Looks like it started in a small hole.

http://s665.photobucket.com/albums/vv17 ... G_0172.jpg

http://s665.photobucket.com/albums/vv17 ... G_0169.jpg

The underside of my piston looks a bit discolored. Possibly running too hot??? I don't know. What does that indicate to you guys?

http://s665.photobucket.com/albums/vv17 ... G_0171.jpg

Thanks for the help.

Jon