Is that a stock piston in my kdx220??

mtaylor · Post by **mtaylor** » 08:17 pm Aug 10 2015

The only markings I can read is a capital letter A.
Without pulling the cylinder off, can someone tell me if thats an oem piston or a wiseco or a ???

Adamnb1 · Post by **Adamnb1** » 08:23 pm Aug 10 2015

I think that's oem. They had a b and c markings.

mtaylor · Post by **mtaylor** » 09:30 pm Aug 10 2015

Impressive if its oem - the bike is 10 years old and hasnt grenaded.

I ordered a wiseco, so ill pull this one out soon and see if its cast or forged.

Anyone else care to guess if its oem/aftermarket?

Rippin_RobMX · Post by **Rippin_RobMX** » 09:39 pm Aug 10 2015

i would guess that its oem and what is that green stuff in the top right of the top picture?

Tioli · Post by **Tioli** » 04:09 am Aug 11 2015

I'm going to go forged.
I think I remember they don't like to machin cast Pistons because of the crustal structure. Cast have a outer layer which is most of its strength. That piston looks like it's machined to shape which is not as important to forged as the structure is the same through out.

Could be wrong

mtaylor · Post by **mtaylor** » 07:56 am Aug 11 2015

nL_Devv wrote:i would guess that its oem and what is that green stuff in the top right of the top picture?

paper towel shoved into the water port

Rippin_RobMX · Post by **Rippin_RobMX** » 08:44 am Aug 11 2015

That's What I was thinking but it looked weird. When is your new piston supposed to arrive?

mtaylor · Post by **mtaylor** » 09:49 am Aug 11 2015

This pic really firmed my belief this is an oem piston:

IMAGE DESCRIPTION
stock 220 piston one letter and an arrow

http://www.kdxrider.net/forums/gallery/ ... age_id=413

New piston in a week or two

kx200 · Post by **kx200** » 12:03 pm Aug 11 2015

I got 7500 miles out of my stock 220
http://www.kdxrider.net/forums/viewtopi ... 1&start=20

canamfan · Post by **canamfan** » 04:01 pm Aug 11 2015

I think it's oem if you look under 220 piston photos you'll see pics of my stock and aftermarket piston. I also see a lot of tiny dings in the top of your piston that I don't see in mine. Those are usually caused by con rod bearings coming apart or something that passed thru the intake and pounded the top of the piston. Like sand getting by the airfilter.

Rippin_RobMX · Post by **Rippin_RobMX** » 07:19 pm Aug 11 2015

mtaylor wrote:This pic really firmed my belief this is an oem piston:

IMAGE DESCRIPTION
stock 220 piston one letter and an arrow

http://www.kdxrider.net/forums/gallery/ ... age_id=413

New piston in a week or two

man not riding for a week or two sucks lol

mtaylor · Post by **mtaylor** » 09:31 pm Aug 11 2015

Not riding for a couple weeks would suck,
thats why its good to have options.

IDRIDR · Post by **IDRIDR** » 12:32 pm Aug 12 2015

Here's the stock piston from my '03.

Tioli · Post by **Tioli** » 02:11 am Aug 13 2015

Well looks like I'm the only one that guessed wrong. Only solution is to stick my head back up that dark spot under my tail and crab walk home.

mtaylor · Post by **mtaylor** » 07:42 pm Aug 13 2015

HOOLLY SHIEEETT!!!

I was too early to say "Impressive if its oem - the bike is 10 years old and hasnt grenaded."
I pulled the cylinder off today and daaaaaamn that piston its trashed!!
How is it that the bike still runs?!?!
There must be bits of aluminum scattered and embedded throughout the bottom end, just look at the connecting rod...

Sure am glad I pulled this apart, but really how much more damage could have happened, its already faaked.
The piston rings sure are effing loose tho.

canamfan · Post by **canamfan** » 08:15 pm Aug 13 2015

That's where all those little marks on top the piston came from

Post by **Julien D** » 06:34 am Aug 14 2015

That bottom end really should be split now. You'll never be sure you got all those bits out otherwise.

Tedh98 · Post by **Tedh98** » 06:43 am Aug 14 2015

Julien D wrote:That bottom end really should be split now. You'll never be sure you got all those bits out otherwise.

Definitely.

I once tried flushing a bottom end. I lost track of how many times I flushed it. The last couple of times the solvent came out clean. I sat there and looked at it and thought I couldn't fully trust that it was clean. Split the cases and found debris still stuck between the bearings and seals.

I'm sure the engine spinning at 8,000+ rpm would have dislodged that stuff though.

Rippin_RobMX · Post by **Rippin_RobMX** » 07:12 am Aug 14 2015

Wow as if the bike still ran

ohgood · Post by **ohgood** » 08:31 am Aug 14 2015

mtaylor wrote:HOOLLY SHIEEETT!!!

I was too early to say "Impressive if its oem - the bike is 10 years old and hasnt grenaded."
I pulled the cylinder off today and daaaaaamn that piston its trashed!!
How is it that the bike still runs?!?!
There must be bits of aluminum scattered and embedded throughout the bottom end, just look at the connecting rod...

Sure am glad I pulled this apart, but really how much more damage could have happened, its already faaked.
The piston rings sure are effing loose tho.

that's impressive damage, but more impressive that it still ran instead of spitting pieces out with each revolution.

good call on pulling it apart, and more testimony to the need for replacing stock 220 pistons.

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