very hi mileage KDX220

[kx200]

How far should I go before I do a top end on my 1997 220? It is street legal so most of the mileage has been on the street.
I put a new spark plug in once a year and change the trany oil . I'm on my 2nd chain and 2nd 15t front sprocket. As of now it has 7300+ miles should I go for 10,000

[KDXGarage]

Why chance it shattering??

[KDXrider1989]

I agree with Jason, KDX 220s are notorious for grenaded pistons. If you know its never had a top end overhaul with aftermarket parts, Id do that ASAP

[kx200]

I have all the tools to do a top and bottom end, but also have 2 other kdx hybrids so if this one goes its no big deal to me. I figured if it has not grenaded the piston in the 7300 miles I would like to see how far it can go. I did take some photos looking up the exhaust port and the piston looks fairly good still. Compression is 160 and did not see much blow-by. I run a oil ratio of 50:1. It does have a FMF rev pipe and stock silencer. It does run a little rich on the bottom so I have a 35 pilot.

[scheckaet]

I figured if it has not grenaded the piston in the 7500 miles I would like to see how far it can go. I did take some photos looking up the exhaust port and the piston looks fairly good still.

FYI some grenade early, some don't... but they all eventually do.
Just a lot of money down the drain to see how far it can go.
But that's your money, not mine.

[KDXGarage]

Sooooo, it is a road bike, and you want it to shatter while an 18-wheler/dump truck/etc. is right behind you.

I am not talking about service limit measured with a measuring tool. I am talking about fatigue life.

[urgreathero]

comon from a bike mech, i wouldn't push it. if you have the tools and you know what your doing, why chance it? you already know its a great bike so what else do you have to prove? :p

[MCKDX220]

Just an observation, 190 psi tells me you have a "tremendous" amount of carbon build up.

Your motor was not designed to run that high of a compression, so you are taking the bike out of it's design parameters.

You are putting an excessive load on the crankshaft and it will be prone to detonation.

If you insist on running 'er at 190 psi and not do a top end service, you should at the very least retard the ignition and run premium, if not race gas.

Normal is ~120 psi and the low end ~ 160 psi at the high end, although from what I have read, those that go for higher compression and get there cylinder heads worked on, typically end up at ~ 170psi.

Just my .02 worth.

Michael

[C George]

My exact thoughts ,,,,,,, 190 PSI compression ????

It would detonate something terrible on pump gas.

[kx200]

You guys are probably right. I have time to rebuild it the way winter is going this year. Just seems strange the 97 is known for having bad pistons and it has lasted this long. Especially that all its life it has been running on Walmart Super Tech TC-W3 Outboard 2-Cycle Oil. Should take some photo of the old piston when I get it apart.

[elusive]

Especially that all its life it has been running on Walmart Super Tech TC-W3 Outboard 2-Cycle Oil. Should take some photo of the old piston when I get it apart.

Interesting! Please do!

[jjavaman]

Don't all pistons eventually grenade? Has there ever been a poll done as to how many people swapped out their stock pistons for aftermarket and how many have had their stock piston explode? I read one person on here preaching the change you piston story hard, yet he admitted he ran his stocker for 6 years!

[kx200]

here is a update on my 97 KDX200 with over 7000 miles

[kx200]

[kx200]

[kx200]

Exhaust pipe inlet

[kx200]

shot of the outlet going to the silencer

[bufftester]

Your compression gauge there is showing 150, right in the money for these engines. What I find more disturbing is that you only change the oil once a year...

[ICRage42]

x2

that and I wonder how well that runs with the exhaust caked like that. You would think just with the diameter change it would change the rev/band on it? Thought mine was bad when I cleaned it.

[kx200]

I could not believe what I was seeing when I puled the head off.