TOPIC:

I found a 650 parts bike and it looks like I'll be getting it this Friday, for $100.00 It's basicly all there with the exception of no side covers and some old crash damage. There was/is no plug in the third cylinder and it is full of dirt/cobwebs/rust, and the engine is locked up like a virgin on a saturday night. I realise that I won't know how buggered it is until it's taken apart, but what have you guys found when opening up an engine with an open cylinder like this? I haven't had time to get more info yet, but it looks like it has sat exposed for a few years (outside). All I want out of this thing are some usable spare parts. Hell, after shipping costs, exchange, yada,yada, the carb rack alone would probably be worth the c note to me, so the rest is gravy.

I have a small Honda that I used a BIG hammer to get the Piston out after it rusted in tight ,, Bored it to 100mm Over and still have rust stains ,,,Tear it down you will see very quickly what your up again ..

i bought a yamaha 1100 once that sat like this for 3-4 years. i soaked the pistons down with wd-40 and pushed it around til it freed up. drove it for 2-3 years and sold it for $1200.00. it never hurts to experiment on a parts bike.

I bought an Ausin Healey Sprite that had been sitting for years with the plugs removed. I had to smash out the pistons with a big cold chisel and hammer. The bores were beyond use, but I had it bored out to 1380cc and used Spitfire pistons. If your bores won't clean up with a regular overbore, might be a good excuse to buy a set of big bore pistons!
Try soaking in oil for a while before pulling it apart, you might get lucky.

i know a guy that put his 3 wheeler thru the ice(pond) in late winter, and got it out early spring, the motor was seized, and he poured coke down the plug hole, let it sit a day, and it could turn over the next day. i didnt see it, but thats his story. i guess the coke ate the rust/corrosion, not sure how great it is for bearings now that i think of it tho...

My son got a Yamaha 175 dirt bike like that. It took me about a week of spraying WD40, tapping down gently with a block of wood, finally came loose. Cleaned it up best we could, put it back together and it actually started and ran, lasted a whole season before a friend of his wrecked it and he sold it for parts. Never can tell sometimes.

I got a GPz750 motor that had been sitting outside with no carbs or exhaust pipes, but with the plugs in, it came from just outside Austin Tx. The motor had 2" of dirt in the two middle cylinders, and would still turn over about a third of a revolution. Pistons were actually in good shape, but the cylinders had to be bored.

If there were no carbs or pipes on the bike, moisture...errr water got in the cylinder(s). When water got into the combustion chamber, it sat on top the piston for about an hour to 24 hours then slowly seeped down the iron cylinder liners towards the oil pan. The rings got wet. The rings/cylinder liners rusted. The rust became like a weld. You can probably save the cylinder head and may even save the pistons but you will likely end up damaging the block when you crowbar it off the rusted-stuck rings/cylinder liner. At that point, you will likely want to get a new block and matching pistons (well used ones at least) off eBay. I have had this happen several times and other than the grunting over the block removal, there should be nothing wrong with the cylinder head and lower end. Be careful not to damage the upper case mating surface when you pry the block off and it would be better to chop the pistons up than to ruin the connecting rods or bearings using excessive force.

Excellent! Thanks all for the experience/tips.

This ain't a tip... it is an experience(s)... several times over. Just try not to gouge up the engine case prying the block off! hehe (that is experience speaking as well... Generally the block will come up about 2" to where all four cylinders are level. USE A PIECE OF WOOD under whatever you lever with.

I got it. This is going to be SO MUCH FUN! I've always been scared to dig deeply into the engine of my bike, because I didn't have a readily available back up parts source. Now I can finnaly get a close look at all the inerds and have a better feel for the "big picture".