KDXRIDER.NET

Hello everyone, first post on this forum. But I’ve stalked it for a while looking for answers on common dirt bike issues. Recently purchased a 99 kdx 220. Was going to ask about being able to identify my piston Through the exhaust port. Seller claimed it had a recent top end replacement, engine is clean and can see new gaskets, but you never know.
But during my carb tuning to get the bike to rev out cleanly from 1/2 to wot I’ve noticed a leak on the bottom of the engine. Didn’t notice it during the test ride because if the skid plate. Removed skid plate and noticed the flywheel side case is cracked around One of the lower bolt boss/hole. Seller didnt say anything about any lower end work. But it looks like maybe something is between the case half’s and was torqued down and cracked. So I’ll see about the piston soon enough. But has anyone had a case half repaired/ welded with any luck? Really not liking the thought of hunting down matching case halfs

Welcome to kdxrider.net. I wish it could be for better reasons. :-(

Talk with a local TIG welder in your area. Also, talk to your local dealership. Although they might not do case repair, they may "have a guy" that they use or may be able to point you in the right direction.

Thank you for reply. Guess I’ll start looking for some welders in my area and see what they have to say

Ah, the joys of PO discovery! It can be welded up, but you would probably be well deserved to split the cases and see if there is any other damage that you can't see. Good luck.

That’s what I am thinking also. Could be some more surprises.

Also consider that if you do split the cases, you might as well be doing main bearing and seals, maybe even have the crank done as well. I would split the cases anyway if it were me. Good luck with it and sorry you find out that dirty secret :(

Just to clarify, I was thinking it would need to be split before welding.

I know tearing it down is the right thing to do. While it’s apart I might as well freshen up the bottom end. Hopefully that’s all it will need. Maybe have some mods done to the top end while I’m at it.

Since you need to split the cases don't cheap out. Get the crank rebuilt with a new rod and lower bearing. I used a Hot Rods kit. Get OEM or better crank bearings and crank seals. Go through the trans bearings, thrust washers, and bushings and make sure they are all in spec or replace them. I think I spent between $700-800 total just on the bottom end of my 220 (all OEM except the rod and lower rod bearing) when I did it but I know it's going to be trouble free for probably another 20+ years.

I have it tore down to where I need a case splitter. Not looking that great inside this thing. Shaping up to be long term project to get it back to snuff.
Need some advice on this cylinder and head please

Last few pics

Head and crank look reusable to me. The cylinder looks pretty worn (of course, I always say that it seems!) but I can't be for sure. I would clean it with a scotchbrite pad and post pics of the results so we can get a better look at the area around the ports and where you see noticeable lines or scuff areas. What you're looking for is bare aluminum through the plating. If any is visible then sending it to be plated is a must.

I was also worried about the chunks on the Edges of the ports. If it’s repairable I’ll send the cylinder out to get replated and piston kit. Doesn’t look I’ll be riding this year now, so I’ll take my time and save money to get this engine completely rebuilt. Thanks for all the replies

repair and replate needed on the cylinder

silly cone is a sure sign of shitty craftsmanship

I'm pretty sure the cylinder is fine to be replated. It would take some serious damage for it to be trashed.

I agree on the silicone statement completely!

It is missing a little chunk. You back on the Everclear? :)

Replate. That look like the original plating, maybe someone will agree. Those ports will need some welds. Head could be lightly sanded smooth. Crank looks fine, check for play in the rod

Head looks great to me. That little dot is factory.

Check the crank for play. I don't see any damage to it. Only tools can check for wear or "worn out".

Thanks For help everyone

KDXGarage wrote: 12:41 pm Jun 05 2020 It is missing a little chunk. You back on the Everclear? :)

LOL! No, not since my birthday.

I was saying the cylinder was fine ie; still salvageable. Yeah, it's going to need a bit of TIG welding on those two ports at minimum but it is still a good cylinder. Should be about $300 or maybe a bit more, if no other damage, for repair and plating through Millennium.