Piston cilinder question

[Jasper]

Hello
I recently bought a kdx200 91
It was a very dirty bike but i dont think it had a hard life
The front wheel bearings were broke, suspension needed new seals, there had lived a rodent in the airbox, reeds were not closing completely
But it started very well and compression is 170psi
I took of cilinder to check piston and to clean powervalves, and noticed that the piston didnt look very fresh(90% sure that it is the original one)
You can twist it a little on the rod and the ring end gap is 0.55
Also the first 4mm of the cilinder show a very little
ring that you can feel...
Now the question do i change it with a wiseco piston kit? Or do i wait
Sorry if my english isnt 100%

[eprovenzano]

First please don't worry about your English... It's fine...

The cylinders condition is hard to diagnose over the Internet. But if it was mine I'd clean it up, replace the piston, rings, needle bearings, gaskets with a Wiseco top end kit. Your current top end is worn out, plus I'd replace them just for the piece of mind knowing it's done.


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[Jasper]

Bought a wiseco piston kit today
When i disassembled the powervalves
I noticed that the left valve had damage on the gear


So now its waiting till tuesday to see if i can order a new one

[Julien D]

Clean that cylinder up with a green scotchbrite pad and some lube and post another pic after. Looks pretty darn good to me from that pic. Good call on the wiseco kit. Might as well since you have it open. That valve may or may not operate properly. Clean and lube it and give it a shot?

[eprovenzano]

I'm glad to see you pulled the power valves. Yea your left valve may work... But I foresee you ordering a new set from BDK Racing. The original are no longer available . Plus they're made from aluminum while BDK Racing uses stainless steel... It's would be the last time you'd have to replace them... I'd reuse your existing one for now but plan on getting a replacement set later on.


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[Jasper]

I'm not going to use it... Fear of fracture and more damage
Stainless steel ones are nice but i'm from belgium and i dont want to pay lots of money on transport costs and so...
And if i can find a good original one, i go for that because if you keep them clean i think they dont fail

Message to belgian people:
If you have a left powervalve or motorparts for sale... Let me know
Its for a 91

[KDXFZRRD]

Spend the money on the aftermarket valves. The stock ones will just continue to break. Every E model I've seen had at least one broken stock valve.

[sthoward]

I'm from belgium and i dont want to pay lots of money on transport costs and so...

The supplier of the steel valves (BDK) are based in the UK so shipping should be very cheap for you.