KDXRIDER.NET

This is what happens to a 220 cylinder, maybe at least 1 to a couple hundred rpm's PAST the point of REPLACING the stock piston. Updated pictures of the piston and the HOLE in the crankcase are as shown.

It appears to me that the plating is gone around the one port corner in the pic

Bought the bike as a project for the winter. I also live close to Eric Gorr's new shop. I will also be contacting RB.

Soooo..... what should I DO!!! Vince, Jeb, CC, and others .... need your help!!

I dunno what you should do. From the pic I can not tell. The cylinder does not look terrible from what I can see. The missing plating around that port looks to have been massaged. A chip or flaking off of plating will usually leave some irregular lines, not nice and uniform like that?

Nothing much coming to mind in the way of advice. However, if you've got a hole in the cases you're looking at finding a set of cases or a bottom end anyway so repairing the cylinder should be pretty low on your priority list.

It's probably best to have replated since it is down for rebuild.Neither my KX or KDX had plating that did not require rework.You are'nt by any chance ybuy on another site are you?

I'd be more concerned with this first...

Actually Inda, that is the least of my worries. I have the piece that broke out of the case. The motor blew up in the driveway. A freind is a very good aluminum welder.

kdx633..... I think BOTH sites are GREAT!!!!!

A little JB Weld and you are good to go

Hmm. I'm not even sure a very good aluminum welder can fix that. There's very little clearance inside between the case and the crank, and that section of the case does hold compression. If it were mine i'd be after new or used cases.

Anyway, assuming you can fix the cases you're looking at....

Welding case
Rod kit ~90
main bearings seals ~50
wiseco piston kit ~130
replate cylinder ~200 (if you're lucky)
Labor for crank rebuild ~60


If you can split the cases and do the rest of the work yourself, you can get out pretty cheap. A shop is going to charge you a few hundred, easy.

J.

I'd try wibs JB idea before I had a hack weld on a cast aluminum crankcase. That will require pre and post heating. Might be a good case for that alumabond propane/mapp gas aluminum welding stuff.

This stuff? http://www.durafix.com

Yeah, that's the stuff. Never used it personally, but have heard of some good results....especially for 'plugs' like this.

I don't know about welding/brazing on that. I think you'd burn the gasket out on either side of the hole.
JB weld seems like the ticket. Until it falls out, anyway

Re: '...that is the least of my worries.'

I'm not a welder..never welded a thing in my life.

Still, welding to cast aluminum..to THIN cast aluminum is said 'round the world to be tough.

...and to a case-half, right at the split? I suppose you would take everything out of the cases, bolt them back together, then try welding the piece in? Is that how it would work? That might help keep heat from tweaking things..but I don't know how you would keep away from the seam. Maybe weld IT after it's all back together WITH stuff inside?

'Glue' sounds good to me!

That transfer port does look to be missing something...but it's quite clearly defined. Plating likes to 'tear' or peel once it's nicked on a port edge.

That's an OEM piston, ain't it? Guess the PO never got the memo on changing the thing out?


Winter project? I guess!!

And a good sized black-hole for $$, too!

Good luck!

WE will be splitting the case's. Redo everthing inside. A to Z.

My freind who will weld it is very good at this sort of thing. I have seen his work on other things, and asures me that it will be just fine. HELL!!! he owns the bike. He bought it because I have a 2001 200 and he likes mine. So he figured, WHY NOT! I can fix this thing. Yaa... I know the two bikes are different, but it will be cool to find out just how much!! If he leaves it "close" to stock.

He knows about my RB mods, so I can't steer him away from those.

C C ....Stock piston?? How can you tell for sure. Hate to have that be a Wisco.

For the less than $500 he paid for it, he belives it is worth it. Besides, the PC pipe and silencer, new tires and other parts on it, he should get his $$ back if he can't fix it.

Re: 'C C ....Stock piston?? How can you tell for sure. Hate to have that be a Wisco.'


I don't know of another cast piston for the KDX than the OEM piece. Haven't gone looking for one, either. Usually there are plainly visible cast marks you can see on the bottom for one thing.

What I wondered about is if someone did a top-end on the thing but used an OEM piston...not so much that it was the piston it CAME with.

That 'cutout' looks like a Pro-x....

When you get a Wiseco next to it, you will see how they differ.

Did you happen to measure the piston/cylinder clearance is? Or..ring gap?

Just 'cuz it's an '01 doesn't mean it has thousands of hours on it.

Piston is not a wisco - look at the rod boss area. What other brand???? don't know. Appears piston seen some excess heat though by the coloring on the skirt - CC may right - worn out piston rings/excessive wear will cause piston to overheat. Nice pictures of the damages - thanks for sharing.

Looking at the case - it does not hold compression like someone stated - but it does need to hold a vacuum and retain the case volume intergrity.

I've seen good welders fix up worset holes without problems. I would definitely have it welded verses using an epoxy based compound. The case will need to be split and then welded: and then dressed in the immediate area of the case seam closest to the welded area. Yamaha bond fills small file seam voids wonderfully.

Nice Ducati Supersport in the background also

It's a vacuum when 'er skirt is up...

..and certainly under pressure when she drops her skirt.



Cranks are like that....




I don't think 'combustion' pressure was intended to be inferred.


I wanna see pics of it all fixed up!

THANK'S Guy's. Your opinion's mean A'LOT!!! That is why i posted the pis's and asked the question.

I also felt the bike was worth it, but now, what do we do with it.
$$$$ mean nothing, to a point, if there the right one's.
Suggestion... Keep them coming!!!

I C... ducati is for sale. 97 900 with 7k on it. $3500 obo.

CC... Pic's during and after it's done are what I'm planning.

Re: 'but now, what do we do with it.'

You answered that already:

'..he belives it is worth it.'

Fix the case, get the innards up to snuff (if the big end of the rod is bad, fix it), modify the carb/head...go riding!!

canyncarvr wrote:It's a vacuum when 'er skirt is up...

..and certainly under pressure when she drops her skirt.



Cranks are like that....




I don't think 'combustion' pressure was intended to be inferred.


I wanna see pics of it all fixed up!

Your right CC - my point should have been we are talking about very small amounts of pressure whether negative or positive. The structual integrity of the cases is what is important. And there is nothing wrong with a skirt being dropped..... well .... I guess there is as this thread pointed out at the onset.

we are talking about very small amounts of pressure whether negative or positive

It's a two stroke engine. Pressure in the crankcase, both positive and negative, is responsible for both pulling the intake charge into the engine as well as forcing that charge into the combustion chamber. A tiny leak in the crankcase can have a huge impact on both performance and longevity. I personally wouldn't want to weld or patch right there on the seam in a pressure sensitive joint.