Well the good news is I located the problem! Hole in the top of the piston directly under the spark plug along with some wear to the "front" side of the piston itself having a small slop on it down towards the piston ring. The service manual says I can replace these without removing the motor (thats how I tore it down). Is it ok to reinstall the top end with it still in the frame? Do I need to remove the bottom end for cleaning????

ps: I tried posting a pic, but to technical for me to do!!!!

 

Holed pistons,wear on the exhaust side of the piston is usually because of heat and running lean in most cases.Plus water can do the same thing, wash the oil film off the cylinder and cause it to run lean and seize.You can do a top end without having to remove the engine. Always try to clean out any debris from the bottom end. There's a 10mm case drain screw at the bottom of the engine.I'd at least try to flush with kerosene/naptha. Pull the piston off the rod and check for any up and down play on the lower rod bearing and for any rough feeling crank bearings or noise. If there is ANY up and down play on the rod no matter how small(side to side play is ok) then the engine needs to be split and a new rod kit,crank bearings, seals, need to be installed.Just my I wouldn't guarantee just a top end job that came into the shop. I've seen plenty top end repairs only where a worn out bottom end would take out a new top end when it started spitting bearings into the cylinder. Just check out the bottom end carefully!

 

Will do. I hope there is no play!!!! I will wash it down and check it out. Thanks again for the advice

 

Plus don't make the mistake that many people make and not bleed the 10mm bolt on top of the head after it's all back together with coolant in it. Just loosen the bolt and bleed until all air bubbles are out then tighten the bolt.Doesn't have to be running.If you don't get the air pockets out they can over heat real quick and cause problems. Cylinder bolts torque to 24-28 foot pounds,head bolts torque to 17-19 foot pounds.

 

I would not have known to clear the air out of the coolant line. Thank you!! I have ordered the top end kit and I have the cyl at the machine shop. Its just a waiting game now

 

The top end kit came in on Thursday and it is all at the machine shop now. I was wondering if you could tell me if there is a break in procedure for the new piston and rings that you could recommend?

 

When I rebuilt engines I set the piston tight(aimed between .0015 -.002 clearance)I'd usually just crank them up on my lift and let them get to operating temperature and killed them.Then I moved on to something else until they cooled down. Then I'd take them out for good 10 minute ride or so,enough that I felt safe enough to turn them over to the owners. I'd still advise them to take it easy,vary the throttle speed,no wide open throttle for about an hour. This was my way of breaking one in. Some believe in breaking them in the way they're going to ride them,fast and hard.. My main idea was to let the rings seat properly along with the rest of the parts and just use common sense.

 

My owner's manual says in part to vary your throttle position, don't pull any heavy loads, don't idle for long periods, and change the oil after 20 hours or 1 month.

 

Great! Thanks guys for all the help. I will put it back together next week when I get the parts

 

Just wanted to update you guys on the project. It took a couple of weeks to find a Sat I had time to work on it again, but it is finished!!!! Great compression, started with very little effort at all. Thank you for all the help and advice on getting this done!!!