We are pretty deep into Super Vintage Hare Scrambles. Got promoted to A class and need more power to compete. Has anyone tried a 220 piston in a air cooled KDX 200?
Are you serious?? You know you'd have to get the cylinder bored to a 220, right? You can't just shove a 220 piston into a 200 jug, unless you've got a really big sledgehammer ;) If you're going to spend the cash to get it bored, I'd send it to Eric and let him work his magic.
Ya Eric Gorr can do it. I would look at a 225cc big bore kit rather than using the 220 piston . He can bore the cylinder, have it replated and do some porting to boot. I'm sure if you give him a call he'll be able to walk you through the different porting configurations to match the power delivery to your needs.
What mm bore is the 225 Big Bore Kit? Is there a data sheet posted somewhere? Have already done port work, squish band and case matching. Trying to figure out how much you can cut out of the cylinder and not run into thin casting problems. Want to stick with nickel plate.
EG's site tells you the bore size of his 225 kit (I'd just tell you, but you should go there to check it out. Link is on the left.)
His 225 'kit' is plated. The 240 kit is an LA sleeve...NOT coated.
Air cooled? Obviously that statement and the 'vintage class' means you're talking about a fairly old bike. I do not know if EG's 225 kit has anything to do with an air cooled bike.
I'm having a Wiseco 225 kit installed on my 220R as we speak. The 1mm overbore and Nicasil was done by Millenium Technologies in WI and the cylinder fine-tuning/installation is being done by Mission Yamaha in Southern CA. This is a magazine project bike and I've been told that 225 is probably the biggest I should go to avoid any reliability problems. It sounds like your mod should work as long as it's done properly (have the cylinder and ports cleaned up before you put it back on the bike--the overbore can get things out of whack)
Hey Jasonwho
I want to replate after the bore job. Just concerned if the wall thickness will be enough on the air cooled jug. Looks like the water cooled units handle it fine. 3mm is required on overbore and the cylinder skirt is already thin. After boring it will pretty much have a knife edge. Don't mind blowing an engine, just can't aford a DNF.
Have done few things to this perticular engine. Full port job done. Head had squish band changed and resurfaced. Running new style OEM piston with the big oval hole in shirt and a hot rod kit. Cases and jug are matched. Stock reeds and DG pipe. Retarded spark 2 degrees. Motul 800 oil and Klotz fuel. Bike runs like a strong Rm125. Not much on bottom end. Winds so high only dogs can hear it. Have done some interesting things to the suspension also. Want to try the divider plate in carb to help with low end loss. What have you tried and how did it turn out?