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Top end life

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Posted by: martian---------------------

I am considering a KDX, but read a post where you have to replace the piston and rings after break in! This seeems crazy. You would think if it were properly assembled at the factory, that it should run until worn out.
Also can you expect to run a season with one piston(trail riding), or do they wear out quick.
My point being, I dont want to have to be constanly working on my bike, I want to ride!
I was also considering a 4 stroke, but like the light weight of the KDX!


Posted by: know_fear---------------------

Kawasaki recommends that you pull the cylinder off to inspect the piston for scoring after the initial 30 minutes of running. I didn't bother with my '00 220 and I never had a problem. I don't know of anyone who did a "teardown" that early.
Because the 220 model had piston failures on modified engines, I installed a Wiseco piston after 25 hours on the stocker. It showed no apparent wear.
I just did a teardown to clean the power valves and the Wiseco looked good enough to go back in with it's original rings after 100 hours.
Bottom line, don't worry just ride it.


Posted by: toalco-kdx---------------------

my bike went about 2.5 years without a new piston/rings. i just replaced them now and they still could have gone longer.


Posted by: BRush---------------------

Total corportate CYA. Normal people don't change pistons after the first eight hours. Not that I'd recommend it, but I've seen a KDX go five seasons on a top end. My own practice is to change the rings once a year. The piston will get changed only if the yearly inspection indicates a problem.


Posted by: fatty_k---------------------

I have seen a 97 220 on a stock piston! That is 6 seasons! My stock piston shattered on my 98 220, but that was after 5 seasons of riding. I say buy it, ride it, pull it apart after a season to clean the powervalves, and check everything out then.


Posted by: Michelle---------------------

My bike had a new piston & rings installed after being run-in, then got left until near the end of last year (99 kdx200). I ride pretty much every weekend, but the amount varies from an hour to a few hours - depending on how much fun I'm having. The previous owner raced enduros, but as he blew out his knee, didn't ride this bike as much as he had others. I wouldn't want to guess as to how many hours it actually had on it, but I know I should've done the piston & rings about 6 months earlier than I did.

You can happily leave the bike at least 1 season - it's definitely not like a MX bike where it constantly needs a top end done. I won't even bother looking at the bike this year, but will check it again next year & do whatever is then necessary.


Posted by: John Harris---------------------

I am on my fourth KDX starting with a 175 and now an 01-200. I have never had even a head off on any of them. Maybe that is an indication of how old and slow I am, but I love my KDXs. They are bullet proof. Unless you are unusually agressive, the bike will wear you out before you need to open the top end. Enjoy, enjoy.


Posted by: Gerg---------------------

I just replaced the original stock piston on my '97 220 with a Wiseco replacement kit. Frankly, other than a bit of carbon on the top of the piston, there wasn't a thing wrong with it!


Posted by: fuzzy---------------------

If you're strictly recreational....You're engine will tell you when it needs rings.


Posted by: MDA---------------------

I know a fella that had a 91 KDX200. He rides fairly aggressively and only opened the head to do a top end after 7 years. At that point he did not find a whole lot wrong with it but decided to redo his top end since he had it open.

I'm not saying this is common, nor good practice, only what I know. I have had my bike for one year and I have not changed the top end. I will probably do it at the end of year two. I will never tell anyone not to do it. Its probably good practice, but based on my experience not as urgent as suggested by the manual.

Have fun,
-Mark-


Posted by: Stan_Flemmings---------------------

My 97 200 has never been torn down, and up until last night, had the factory tires! I'm not saying this is common, and I'm sure many people will disagree with never having it apart, but like someone else has stated, you're bike will let ou know when it's time. Mine just hasn't yet. When it does, I'll rebuild it.


Posted by: canyncarvr---------------------

re: 'This seeems crazy'

Well it is. Kind'a.

I'll bet'cha that if fatty had the opportunity to replace the piston before it grenaded the bike, he'd gladly have done it.

As noted, the 220 piston is known to have problems. Not only on modified, aggressively ridden bikes either.

On the far end of that spectrum, if you have a '97 with original equipment tires it likely isn't too much to worry about.

HHhhmmmm....I change tires 3-4 times a year. Maybe someone is knifing my knobbies off when I'm not looking? Nice of them to sculpt them so roundly, then.


Posted by: martian---------------------

Quote:
Originally posted by canyncarvr
re: 'This seeems crazy'

Well it is. Kind'a.

I'll bet'cha that if fatty had the opportunity to replace the piston before it grenaded the bike, he'd gladly have done it.

As noted, the 220 piston is known to have problems. Not only on modified, aggressively ridden bikes either.

On the far end of that spectrum, if you have a '97 with original equipment tires it likely isn't too much to worry about.

HHhhmmmm....I change tires 3-4 times a year. Maybe someone is knifing my knobbies off when I'm not looking? Nice of them to sculpt them so roundly, then.



Posted by: martian---------------------

Thanks for the good info re: Top end life, I think with the info you all provided me I will definitely buy the KDX. Still haven't made up my mind on either the 200 or 220.


Posted by: Tom Ludolff---------------------

I think it was CC that said: "No Replacement for Displacement" I'd go for the extra 20cc's. You can always tune it for more top end: PC Pipe and silencer, High tension reeds, bigger carb or bored carb, porting, head mods, you name it. At least you have that extra 20cc's!!! And you start out with lotsa low end!!! At least that was my thinkin' when I went bike shopping!!! Bike shopping is a blast!!! Have fun!!! I'm sure you'll love either one!!!

Tom L.


Posted by: canyncarvr---------------------

Yeah...I've said that...somewhere in all my blather it's bound to be there!

...but I certainly did not originate the phrase. The most profound thing I've ever come up with (that I recall) would be more along the lines of, 'Where's the beer?' Or maybe, 'Help! I've fallen and can't reach my beer!'

Consider what it is you're after in a bike (within the kdx realm). If you will tend more toward hi-rpm, hi-speed fun, then a 200 may fit the bill. If all you will ever do is chug around technical stuff, the 220 may suit you better.

It's more than just a matter of size (but of course, size does matter).

The 200 has a larger carburetor (35mm vs: 33mm for the 220). There's a reason for that!

The 200's port timing is considerably different. That's why it will always outrev and outrun the (stock) 220.

AND the 200 comes without an o-ring chain! That allows you to almost immediately upgrade your final drive, cuz it will wear out in a few months <insert jayhawk chain comment here>.

Take a look at this: 200 vs: 220 shootout

http://justkdx.dirtrider.net/200vs220.html


Cheers!



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