What size piston is this?

[NM_KDX200]

I bought a Pro-X piston on Ebay 2 years and am about ready to install it. But...I wanna make sure first. The box say ProX Part No. PX-4312, Piston kit KDX-200 .020, 66.50 mm. The piston itself has a .050 stamped on it (I hope that corresponds to the .50 mm in the 66.50 mm part...). I measured it with my dial calipers and get 2.610"

So....is this an A, B, or C piston?

Once I get the cylinder off, I can measure the ring gap but I'd rather not take things apart right now if this is the wrong piston.

Thanks!

 

[jdbrusch]

The piston is .50 mm bigger than the original bore and stock piston.I believe you have a 96 200(with a plated cylinder) which cannot be bored unless the cylinder has been sleeved.
If the cylinder is plated still and within spec you will have to order a new piston A,B,C or D and rings for the bike, unfortunatly you cannot use the ones you have now.
If the engine has been sleeved then you can take it to a shop and have it bored,but if its on the original bore size you have 1 piston between the stock size and the .50,so you might still want to go with the .25 and keep the .50 for the future.

 

[canyncarvr]

Hertz...and not exactly.....

Check the part number on the Pro-x website. What you have is NOT an a/b/c/d piston.

Try to stick it in a 'std' 200 and you'll have to use a very big hammer! ;)

re: bores, plates and stuff.

Plated cylinders can certainly be bored. Then they are replated. USChrome, Langcourt are just a couple that do this.

FRP will do it. EG (forward motion) will do it.

I'M doing it to my damaged cylinder.

You can get it bored to whatever you wish. EGs 225 kit consists of a bore and replate (with a wiseco piston).

The rings are all the same......the piston alpha desigation is only about 1/2 a thou..so it's not a great big deal. Still, the better the fit, the better.

Clear as mud?

Ask summore...and keep asking until you get the right answer (don't know how you'll figger THAT out.....;) )

Check HERE for a pro-x size chart.

..edit..
It's attached to post#12

 

[jdbrusch]

Sorry Nm_KDX200 and Canyncarvr I thought Nm was trying to do a basic top end,put in a new piston,rings etc.and had bought the piston for a stock bore size replacement.You are correct the cylinder can be bored out and replated for the oversized piston without installing a sleeve.
Boring and replating with the Pro-X piston you now have(.50) would give you a new engine size of 201.704 cc's.

 

[NM_KDX200]

Found the Pro-X site and identified the piston and I see where it sits now. Cylinder is stock, plated, and "B". Fortunately, I just won an Ebay auction for a OEM B piston with gasket set and other goodies. I know that opinions are mixed on OEM pistons but I got it, so I guess I'll use it. Will Ebay the piston I have now unless someone wants to make an offer on it.....

And it may be that I'll get the bike apart and find everything in fine shape. I don't know- this is my first tear down since installing a new piston 2 years ago and I guess I'll find out how well the bike's been "wearing".