Rebuild needed

[jmutiger]

Hi Guys,

I had my piston skirt crack and lodge itself on the big end of the rod.. I'm gonna have to split the cases to remove the bits and pieces..

My question is this.. What are my options for gaskets? What about Pistons? Should I do a whole new rod + big end bearing while the cases are split?

Thanks,

Jon!

 

[IrishEKU]

Go with the Wiseco piston and parts. The OEM kits for your seals work fine. Seince you will have the case split I would go ahead and feplace the shaft seals and the rod berings. If there is no damage to the shaft and rod you don't need to replace those unless you want all new components.

Phillip

 

[JasonWho]

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[Filthy McNasty]

I should let you see a digital pic of my '97 220 piston. I pulled it just in time. I was just doing a routine top end, but I have a harline crack on the thin portion of the skirt. Very scary. Sorry to hear about yours.

 

[jmutiger]

I think mine failed because I never replaced the piston. I bought the bike at the beginning of this season, and just started racing it.. I did all the external greasing ect.. rebuilt the forks ect.. But I left the motor alone after doing a compression check on it, and it was making 150psi.. I was thinking that a rebuild was only needed to increase performance.. Now I know better, a rebuild is a really good cost saving measure, and might save you from the financial agony I'm suffering now. Turns out the big end bearing is munched just enough to warrant replacing it too.. So, after all is said and done, I'll have a fully rebuilt 1999 KDX220.. And I wanted to get a YZ250 too... I think I'll have to continue racing this thing for another year if I want to ever get out of the red.

I'm going with stock stuff as replacements, as I've had good luck in the past with stock stuff.. And the Moose Racing gaskets are commercially available, but according to my dealer the canadian distributor doesn't stock them.

Jon!

 

[Filthy McNasty]

I would very strongly suggest wiseco pistons for the 220. If you do a search for wiseco or piston problems in this forum, you will see about a hundred posts on the topic of the weak stock piston. The 200 seems to be OK, but the OEM 220 piston is not what you want to put back in there. Call up Jeff Fredette, and he will tell you the exact same thing. In fact, the following quote is from his site, where you can order the wiseco:

Hi Quality piston kits for the KDX 200/220. Highly recommended for the KDX 220 do to stock piston's breaking.Kits come complete with Piston, Rings, Pin, and Circlips.

Good luck

 

[Robcolo]

Just looking at the inside of the skirt on that stock 220 piston will scare the daylights out of you [paper thin & sharp casting edges] -- I replaced an almost new OEM with a Wiseco which is horribly noisy. Some of the Weiscos had a problem with the circlip fit [mine fit ok] --it wouldn't seat properly at the end of the wrist pin. Several of these worked loose -according to Sage- and did major engine damage. Somebody in past threads suggested Pro-X or another brand which might fit a bit closer to the cylinder and would hopefully run a bit quieter.

 

[xr400forever]

I am going through the same dilema right now as to what piston to order for my 2000 220. I wanted a pro-x for it but they do not make one at all! I have had a couple of good sources (high per shop and a mashinist specializing in bikes) warn me off of forged (wiseco) pistons for 2 strokes. I ended up ordering a stock piston. I hear too many bad stories about wiseco.

 

[Filthy McNasty]

The pro-x piston is an OEM piston. They buy the overstock from Kawi and you can get a piston to match your cylinder size stamping. These will have the same failure problems as a stock 220. Wiseco forged pistons are indeed more sensitive to start up seizure, but it's not a big deal as long as you're aware of the limitations of the piston. To prevent the cold seizure with a forged piston, just give the bike a nice, easy warm up. Then, you're good to go. I feel that the additional care necessary in the warm up of a wiseco is a better alternative than unexpectedly fragging an OEM. Tons of posts on this subject in the KDX archives. I read most of them before I made my decision.

http://dirtrider.net/forums3/showthread.php?threadid=36897&highlight=wiseco+220

http://dirtrider.net/forums3/showthread.php?threadid=32485&highlight=wiseco+220

Quotes:
I JUST SPENT $1400.00 ON A CRANK/ROD/PISTON/RINGS/CYLINER ETC. BECAUSE OF A BROKEN SKIRT ON AN OEM 220 KDX.

If you are running the stock piston I suggest you get a Wiseco piston kit for it. The stockers have been known to crack from time to time, not on every bike but more than is common with the 200's or any other bike for that matter. I put one in my 220 when I had it.

cracked piston
i'm still rebuilding from a piston that shattered. The bike is a 99 220 and it shattered right after labor day weekend of last year. 600 dollars later still not as good as new. i'm not sure if the piston cracked because it was in there so long or because of a defect.

 

[Filthy McNasty]

Couldn't resist, these are the best of the best on the subject. These guys (BRush and Canadian Dave) are some of the most knowledgeable dudes in KDX-land:

The 220s have had some problems with pistons cracking (the 200 piston is fine). Not every piston is defective (probably the majority are fine), but insofar as I know there's no way to tell if yours is one or not. The consensus seems to be that if your bike is basically stock, you don't have as much to worry about as someone who's done mods to increase the engine output. You may never have a problem in either case. It's not like there have been exploding 220's right and left, so if it was me I'd chance it until winter maintenance/top end time came around then replace the piston - but that's my own personal tolerance for risk. If you are someone who switched over to Goodyear tires on your Ford Explorer the day after the first news reports about the Firestone Wilderness A/T, you may want to take action sooner.

BRush has hit the nail right on the head. Yes there have been occasions where the stock 220 pistons have cracked. Is it going to be a concern for every 220 owner, certainly not. There are some common denominators however than can help you decide if exchanging your stock 220 piston for a Wiseco is warranted or not. 220s that have been modified to deliver more power, bikes that are ridden hard and pistons that have seen a more than average amount of service will all be more prone cracking. I don't think every 220 owner is sitting on a time bomb by any stretch of the imagination but if you've installed a pipe and are an aggressive rider than you might consider replacing your stock 220 piston a little sooner than you might normally and when you do I'd suggest installing a Wiseco. Even if your 220 is stock I think its worth the extra piece of mind to go with a Wiseco when you service your top end. Whether you rebuild your top end sooner than you might normally is totally depended on your comfort level. I like Brush's Firestone analogy. There's no sense going with a potentially weaker stock piston when the Wiseco piston is readily available, cheaper and has a reputation for good service in 220s.

 

[Canadian Dave]

The KDX220 is known to have problem with the piston. On stock bikes it doesn’t seem to be much of a problem, in most cases, but on a modified KDX220 or one that’s ridden hard you hear about stock pistons cracking now and then.

jmutiger you'll certainly want to install a Wiseco piston vs the stock replacement piston or a Pro-X with is basically a surplus piston from Kawasaki etc. supplier and therefore prone to the same problem you've already experienced.

As for rebuilding the bottom end while the case is split . . . . That's what I'd be doing. Given your bike is almost new I'm sure everything is well within service limits still but I'd hate to find out a bearing etc has been damaged by a piece of the broken piston and have the split the cases again half way through 2003. You should have no problems getting replacement bearings for the crank from a local bearing supply shop. They'll be exactly the same as what Kawasaki used but about 50% of the price. I wouldn’t hesitate to use either the stock rod of a Wiseco Hotrods rebuild kit.

David