KDXRIDER.NET

I have one of these, nice and new. I discovered it yesterday in my box of 'special' stuff.



I've just bought (and waiting delivery) a new Kawasaki piston for a '87-'88 200 to compare it to the impossible to find '83-85 Kawasaki piston.

The next issue will be rings. I'm wondering if the 175 rings will work on the later piston and as l have a set to check with, I'll look into that too.

ALWAYS nice to find hidden treasures inside the hoard.

Break out the micrometers when you can. Maybe one day we can all figure why it is different.

There is nil stock world wide of a piston/rings suitable for the '83-'85 200.

Plenty of people looking but other than getting a piston made (l made a couple of calls, not keen on making a 2 stroke piston and one maker that would look at the job was talking $300 plus each for a batch of 20) I'm looking at if the later model air cooled piston will work with minimal mods and be as reliable as the correct piston.

A '83
B '87
C I75 This is here because its also 66mm and l think the rings will be suitable for the '83 piston. They wont fit the '87 piston as the ring grooves appear to taper inwards and so the ring won't fit into the grove like it does on the 175 and '83 200.
Its not suitable in the 200 as the small end is around 3mm closer to the crown.

The skirt window is centre and the ring pins are marked.




The exhaust side shows the lube holes for the bridges between the exhaust and power valve ports on the '87.


Piston weights and the ring pin locations which l checked twice. The left side pins are in line and on the right the '87 pin is further outboard than the '83 . The inlet port may be wider and explain that difference...
The extra weight looks to be more metal around the lube hole area.


Both 200 pistons are the same height, ring groves in the same locations (the different profile of the groves is visible here) and small end is in the same location.



If l fill in the lube holes in case they're uncovered by the exhaust port in the '83, check the reason for the different pin location is the inlet port width and so shouldn't be an issue with the inlet...but maybe the transfer is close.

Have l missed anything ?

what about the height of the pin location i didn't see that mentioned or i missed it.

Thanks for all your effort

Both pistons are at bdc, 58 mm down with the crown level with the transfers.




There's a big difference in the size of this port between barrels.
How much of an issue is this going to be ?



The lube holes for the bridge on one side makes a brief appearance.



So the only real issue is how to resolve this ring end in this port at the bottom of the stroke.

Chamfer the edge of the port...fill the port in where the ring is exposed, run the bike with the top ring only....or not worry about it ?

http://www.x-h2o.com/index.php?threads/ ... ton.39091/ see post #15, Would this be a last resort? Not something I think I would be capable of, but it's another option.

Asewell wrote:http://www.x-h2o.com/index.php?threads/ ... ton.39091/ see post #15, Would this be a last resort? Not something I think I would be capable of, but it's another option.

I'll look into that. I think it might be easier than welding up that port a bit and better than running 1 ring.

It might be the first resort

Is there a concern over the oil holes being open?

Jason wrote:Is there a concern over the oil holes being open?

I think because it's a pretty simple thing to eliminate, it's worth doing.

I had a chat to a piston bloke about relocating the pin, I'm going to find out about moding that port too.
If you do the port, then you can stick a new standard piston in any time...and the barrel will last a lot longer than a piston.

KDX Geoff wrote:

Jason wrote:Is there a concern over the oil holes being open?

I think because it's a pretty simple thing to eliminate, it's worth doing.

I had a chat to a piston bloke about relocating the pin, I'm going to find out about moding that port too.
If you do the port, then you can stick a new standard piston in any time...and the barrel will last a lot longer than a piston.

Just to clarify, just in case, I meant the little holes on the piston.

Are you looking at getting the cylinder port epoxied over?? That won't last as long as a normal cylinder from what I have read.

BUY, ince you have 900 awesome KDX's, you won't ride that one a terrible amount.

Did you ever find anything out

I'm trying a piston in a barrel tomorrow night.

drum roll please...

Jason wrote:drum roll please...

He didn't make the meeting

It's a Wossner piston, l think the bottom ring groove sits a bit higher on the piston but l need to get the barrel, Wossner and Kawasaki piston together to be sure.

im excited to hear what happens

Disclamer.

The barrel l used is off my shelf. I didn't sleeve it so l assume it's just a normal barrel that is out there and representative of what's being used.

If you buy one of these pistons for your 200, please do some basic checks that its going to be suitable of your bike.




The ring peg and thus the ring end are exposed in the port with a power valve piston in a non power valve barrel.


This is a standard Wossner piston for a P/V 200 in a non P/V barrel 58 mm down the barrel. At that point the top of the piston is level with the bottom of the exhaust port.

2 things are different between the Wossner and Kawasaki pistons.

The ring pegs are on different sides to each other, that is on one piston the top peg is on the right (Wossner) and on the Kawa is on the left. I've not seen that this is an issue in itself, it just moves the peg issue to the other port.

The second thing and the reason this piston works in this barrel is THE BOTTOM RING GROOVE IS AROUND HALF A MM CLOSER TO THE PISTON CROWN.
That half a mm or so is enough to stop the ring pin and end from entering the port thus eliminating the issue of the ring end potentially getting caught up in the port.




Have a look.

http://www.wossnerpistons.com/products/ ... =ascending

VERY INTERESTING! Thank you for the info!

VERY COOL. So did it end up running? Or did you never try?

My 200 has a 240cc upgrade and I'd been having trouble finding a 72.5mm piston so l was looking at having to put a standard topend back on it...plus, how many times have people asked for a Kawasaki piston or something else that fits.

I decided it was time to see if there was a suitable replacement without the ring in the port issue, then l found my new 72.5mm piston kit for the 240.

It'll work better than the '86 piston, that's for certain and if no one fits one, I'll end up doing it myself

I just don't want to go back to 200cc from 240