Maintenance & Technical > KX500 Original

Piston and Porting Questions

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BigGreenMachine:
Well I took off the topend. Found a sleeve, some of the ports aren't matched as nice as others. Looking for some pics of a good mid/top end port to copy. Measurements?

Also the piston has "ART" on the side around the wristpin location. Stock or aftermarket?

I have OEM rings here. Wondering can I use them on the sleeved cylinder?


Thanks.

BigGreenMachine:
Some pics of the bore and side transfer (?) ports along with one of the exhaust ports. Whats with the raised section on the exhaust port?  :?

Will it hurt to match the cylinder to the sleeve on the transfers?  :? Whoever did this didn't even chamfer the ports.  :roll: Not finding any markings on my cylinder either. The sleeve hasn't moved if any of you are thinking that. Its perfectly level on top. I thought that was my problem at first.

Well please add some input, I can't learn from you guys if I'm just talking to myself.  :lol:

cheers.

hughes:
Matching the sleeve with the ports is not that hard with the right tools and a steady hand. Those sub exhaust ports should not really require any chamfer or very little. The larger exhaust port and intake ports will. The rings can expand into the port and break off or most people call it snagging a ring. The chamfers help to ease the ring back into it's ring groove. Photo's are very dark and hard read. To much chamfer can effect horse power in a negative sense. All my hot roding 2-stroke skills come from years of marine engine work but some and same theroy still apply to all 2-strokes. Hope some other can give some input. Need better photo's.

KXcam22:
I agree with Hughes.  Get us some better pics and we will be able to steer you right.  I have ported many bikes with steel liners (in the old days). Cam.

doordie:
At first pic something is wrong,it shouldn?t be any bridge at inlet,you got the oldstyle
barell before -89. :?

Sleeve seem twisted a few degrees wrong too.
You should chamfer all ports,but this barell need reboring first,just my 2 cent! :wink:

This is MUN`s portmap of a 68 rwhp old style barell,if you want "more power" it`s to much to handle for most riders. :evil:

//Doordie

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