Case repair?

[KDXGarage]

Sorry that it is in the current shape. Look forward to when it is fresh.

[ToJo]

I seem to have this kind of luck with dirt bikes. No matter how well I look them over I always get shafted, just another day in the life. I’m excited about getting this one fixed up though.

[kdxsully]

Don’t feel bad. Almost every used dirt bike has a dirty secret. Or two. Or three.

[pumpguy]

That crack in the case has me concerned. After I got mine, formerly a 220, and now a 200, I learned the whole story.

The PO bought it as salvage from an out of state dealer, the engine a victim of the notorious 220 OEM grenaded piston. The PO not only replaced the top end, but the cases too. My cases have no S/N stampings. In the process, for whatever reason, he converted it to a 200.

The point I'm getting to here is, that crack in the case was caused by something, and after you get the cases split and can see the whole story, you might find more damage than just the crack you can see form the outside. For your sake, I hope I'm wrong.

Best of luck with your build.

[ToJo]

Wanting on a case splitter, then I’ll see what’s going on inside there. At this point nothing will surprise me.
When I rode it it shifted fine, and pulled hard to about 1/2 throttle and signed off hard. Did some jetting and it signed off about 3/4 throttle and leveled off. What I’ve read about the 220’s that is about normal? Has the FMF woods Pipe, not sure about the silencer. All I have to go by power wise is a early 90’s kx125, Xr400r and a newer xc250. Would love to have the XC low end Torque with the kx125 top End power

[bufftester]

A 220 with the woods pipe going flat at the top is about right. The rev pipe is a better choice, but you can also go up on the carb to a PWK35 and gain some top without losing much grunt at the bottom. Depends on the kind of riding you want to do.

[SS109]

I have no loss of bottom end using the FMF desert pipe along with an RB modded carb and head mod. Midrange is really strong and with a much extended top end. My bike lugs better than my buddy's YZ250X and as good as my other buddy's Beta 300RR. Of course, it all depends on what you want out of your bike.

[ToJo]

I loved the xc250 I had, other than always getting a bad case of whiskey throttle it the rough stuff! I was way to inexperienced for that bike.
Not sure how this forum stuff works, not sure sure if I should start another thread or just keep posting on this one. Still waiting on case splitter and was looking things over and doing research. Came across jetting issues and the needle jet being oblong. So I took a few pics of mine. Took a bunch trying to get something worth posting on here. Not sure if this one is out of round, shadows or just my old eyes.

[KDXGarage]

Tojo, if you want to start a new thread about the carb, that is cool. It does not have anything to do with the cracked case. Someone that might know about the carb might skip this thread if they know nothing or are not interested in cracked cases.

You are the OP, so however you want to do it is fine with me.

[ToJo]

Ok, thanks

[doakley]

I’m going to agree 110% with SS109. RB modified carb and Head, FMF desert pipe give me no loss at all of low end, actually more I think, and revs forever with no flat spots anywhere in the Rev range. This sucker boogies! (Way better that I do!)

[doakley]

Hey, SS109, I’d be interested to hear how you think your KDX compares to your buddy’s YZX?

[ToJo]

Finally got lower end split and it looks bad to me. But I don’t weld for living so maybe there is hope. Once I get this bottom end sorted out I’ll be looking to perform the mods mentioned. Thanks for the advice

[bufftester]

IIWM I'd be looking for new cases rather than welding it up, as it appears it will need some machining afterwards. Those are major cracks and it should probably be subjected to a dye penetrant inspection as well. Interesting drag marks in there looks like something (a 220 OEM piston perhaps?) came apart and attempted to stop the crank from spinning so fast. Ouch...

[ToJo]

I’m thinking The same thing, just bite the bullet and buy new case Halfs or a good set of used ones. Don’t want to do this again if it’s botched. PO said the top end had about 10 hours on it. Probably should’ve said 10 hours ago the stock piston flew apart. After being misled on every bike I’ve purchased, it’s going to be hard to take someone’s word on used cases. This forum seems to be full of good advice and honest people. I’ll post that I’m looking for engine cases on here and see what pops up. Thanks again everyone

[JimmyB]

Wow really sorry to see that. You bought it like this?, How did it run when you went to look at it and test ride it. I am amazed it didn't seize up with the 2 cracks at the front of the case, was there any sealant over the front cracks? was possibly sucking oil from the tranny too...

[KDXGarage]

Ouch! Bearing is rusty, too.

[SS109]

Wow, that's bad. I would definitely replace and not attempt to repair that. Sorry my man.

Hey, SS109, I’d be interested to hear how you think your KDX compares to your buddy’s YZX?

IMO, the YZ250X is almost a more modern KDX just with way better stock suspension. Ergonomics are a little different but surprisingly similar. However, the X forces you to ride on the tank where the KDX you can be more lazy about seating position. It rewards aggressive riding yet can just plug along with no issues following kids/beginner riders. Clutch feel is lighter and has a better engagement range than the KDX. If they would only add a 6th gear it would be much better. Adding electric start would be another big plus.

[KDXGarage]

It might be repairable, BUT... time and trouble considered, end result and finally price and total benefit comparison...


just shop for a set of used halves. People are still parting these out on eBay. Check craigslist and Facebook Marketplace (Letgo, etc.) for a parts bike.

I am sorry you got lied to by a POS PO.

[kdxsully]

That really sucks. Even if it’s welded there’s a high chance it could crack again. Looks like someone torqued the case bolts to 60 ft lbs and said “that ain’t going anywhere.” Find some used, matched case halves.