This is the most advanced piston available for the KLR! Gas ports for the top ring, piston lighter than others, broached slots in the wrist pin hole for improved oiling, updated second ring design for oil control. Tightened up tolerences on the ring grooves and acumulator groove to eliminate ring flutter and wear. Premium ring set. The stock ring, piston, wrist pin and circlips weigh about 640 grams. This exclusive piston kit weighs 490 grams. This engine setup is much smoother than stock. The next batch with come with spiral type retainers for the wrist pin, since some people are having trouble installing the stronger aftermarket circlips. Probe Industries has done a nice video here showing how to install the spiral lock. I'll get one up soon. At this time, only the current new 685 and 692 use these. 

https://www.youtube.com/watch?v=wBkguaftmR0

Oversize piston kit, fits 1996 and later KLR650. Forged, lightweight, 3.00mm over stock. Premium rings and wrist pin. Requires cylinder machining. This kit includes required gaskets : fitted head gasket, base gasket, exhaust headpipe crush copper gasket, cam chan tensioner gasket.  Lighter and smoother than the factory setup. If you have an oil user this is a good way to go.

Improved performance and smoother engine. Much greater difference than expected for a 41cc increase.

This kit originally designed to be used when you wear out your 685. You can also go straight to the 692! This is a big as you should take the stock liner.

We are supplying Kawasaki OEM head gaskets. The head gasket is cut for the oversize bore.

 I highly recommend installing a ThermoBob on every KLR650, especially those with a big bore kit. This helps the cylinder stay round.

IMPORTANT - these are considered racing parts, and there is no warranty. The performance and function is entirely dependant on the quality of the bore and honing, and install process.