KDXRIDER.NET

Hello to all,

I have recently purchased a 98 KDX knowing that the bike is going to need a little work. So I have pulled the top end on the bike and see that it is going to need some welding amd then replated. I have heard a lot of good things from Langcourt. My questions is do you think this cylinder is damaged beyond repair? Any help would be great.





Thanks

give it a quick hone and see if you have any flat spots.

I will have to order the honning tool that attaches to a drill. The only thing that really concerns me are the scratches on the inside. It looks as if someone did not mix the fuel correctly or just did not add any oil in the fuel at all. Typically do they weld first then plate if the scratches are to bad?

yes weld first then plate forget the hone that needs welding and a replate

Ok thanks, it does look like it will be able to be fix right? This bike has been one fun project. Ground up restoration.

yes they will weld deep scores machine the bore and replate should be as good as new.

You might also consider going to a larger piston. If you use a piston from a 220, DO NOT USE STOCK OEM, they have a history of grenading. If you go this route, you will also need to modify or change the central KIPS valve.

I am going with a Wiseco piston. I have read a lot of bad reviews about the stock piston. Def going forged with the piston.

First, never hone a plated cylinder. The plating is very thin to begin with and honing would cause you to get into the aluminum base material. That would be very bad if you try to run the engine that way! You can ruin the cylinder or, at the very least, cause the repair/replate to cost way more than it should. Plus, you would destroy a perfectly good piston and your new rings. Anyways, if you can catch the grooves in the cylinder with a finger nail then it will have to be replated. There was a thread recently on who to use (and who not!) to replate the cylinder so I won't get in to that here.

Second, for the most part, forget going to an overbore as you would still need to have the cylinder plated, some you completely lose the power valves, and the power gains are not worth having to get a special piston on your next rebuild. If you do decide you want a "big bore", make sure to have someone like Eric Gorr do it as he has the experience to clearance the power valves and work on the porting so that it all works together.

FYI, there is nothing wrong with the stock 200 pistons. The cracking and failure issue is ONLY with the 220 pistons. However, a Wiseco is a good upgrade even for the 200 IMO.

Yup, that needs welding and re-plating.

Thank you guys for the information. I am going to send the cylinder to Langcourt so they can weld and replate. It will cost around 200-250 depending on their review of the cylinder to see how much work it will require. Have you guys ever used them?

And one other thing, what the best way to remove the studs from the cylinder?

Langcourt has a very good reputation. Make sure to send them the piston you are going to use as well so that they can match the plating to it.

I use the double nut method to pull the studs or you can purchase a stud remover from Snap-on or one of the better tool suppliers out there. If you use the double nut method I suggest going to the hardware store to get some Grade 8 nuts to use instead of the ones used on the bike. This way if you end up damaging them it isn't a big deal. If you damage the factory head nuts then you would have to order new ones from Kawasaki.

Ss109 I looked at your kdx restore and the bike looks amazing. Good job! Thanks for the info on the stud removal. Do you think my cylinder has been sleeved? The reason I ask is on your pictures of your kdx cylinder it does not have the 1/4 or so ring around the cylinder like in my pics. How could I test to see if it has been sleeved, mabye a magnet?

A magnet will tell you if there is a sleeve in there. And SS109 said grade 8 but being that they are metric you would be looking for 10.9 or 12.9. It can be hard to tell what grade nuts are because they don't tend to mark them in any standard way. But if the nuts are cheap then they are soft.

rbates9 wrote:And SS109 said grade 8 but being that they are metric you would be looking for 10.9 or 12.9.

Good catch!

A pic from the bottom will make it easier to tell if it's sleeved, or one with the focus on one of the ports. The ring around the top may be from the head gasket. Looking at the intake port in the first pic makes me think it may have a sleeve.

So if I get a pull form a magnet it is def sleeved? I will take some pics from the bottom and also the ports.

If it turns out to be sleeved should I buy a new cylinder? I do not want any heat issues. Or should I just get it bored out and buy a new piston? I was really hoping to go back to factory specs but if its sleeved I guess I cant