Replacing a 2-Stroke ATV engine's Cylinder Sleeve
We're use either L.A. Sleeve or Wiseco Piston and Cylinder Sleeve kits to repair ATV and small motorcycle engines back to like new, or to increase their power with a big bore kit. Not shown, is boring out the old sleeve. ( note: our YouTube video http://www.youtube.com/watch?v=AoVrClGmLMo shows removing/boring out sleeves on a similar job.) While we were removing the worn original sleeve, we had placed the new sleeve in a freezer to "shrink" it in diameter. Once the original sleeve is bored paper thin and peeled from the ATV block, we inspect the block for any signs of distortion, fatigue cracks, or other wear and tear. With the block OK'd for re-use, we align the frozen sleeve over the block's bore and use a small hand-pumped shop built hydraulic press to press the sleeve firmly into place. We prefer to use a small hand operated press instead of our larger powered press because, with our many years of experience, we can "feel" how the sleeve fits into the bore. The precision fit of the sleeve is important for not only locating and holding the sleeves in place, but also to ensure proper heat transfer while the engine is running. If its too tight, broaching may occur while pressing the sleeve in; which can not only shift the sleeve off center, but also create a "hot spot", where the sleeve cannot transfer heat evenly and may result in a scuffed piston. If the sleeve fit is too loose, it will not transfer heat efficiently, and eventually work loose in the block. Loss of power, blown head gasket, etc are signs of this. So, we prefer to press the sleeves in using a hand operated press, so we know they fit right, the first time, every time. After the sleeves are installed, we check the fit of the piston. not shown is measuring the cylinder with a bore gage and miking the piston to ensure the correct clearance. For more info on block boring and other performance engine work, including 5-axis CNC head porting and flow bench testing, please call Automotive Machine & Supply, Inc at 1-800-210-8675.
2 Stroke Porting chamfering the port part 1.mpg
Porting and Polishing 2 Strokes. How to chamfer a port window on a 2 stroke. Using a right angle tool for porting makes chamfering the port opening on a 2 stroke fairly easy. Here is a quick technique for porting to ease the transition of the piston ring into and out of the port opening to the combustion chamber. Tips from CC Specialty Tools online @(ccspecialtytool.com)
KTM 200 EXC Racing engine rebuild
KTM 200 EXC Racing engine rebuild new crankshaft, bearings, piston&rings