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low compression, and a stuck pison ring

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darrengee

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I just acquired a free 96 GTS from a friend. It was left out in the rain with the seat off and the carb was full of water. The engine was seized, but I broke it loose by soaking the cyls w PB Blaster and WD-40. I rebuilt the carb, and got it to run. I did a compression check and the rear cylinder is 153psi, but the front is only around 65psi. I pulled the head and everything is clean (domes, cyl and top of piston). When I twist the piston, I noticed that the top ring moves with it (stuck to the piston). The cyl with the good compression doesn't do that. What do you guys recommend I do to get the compression back up without sinking a bunch of cash into it? You think I could just re-ring it? The cylinder is virtually scratch free and I can't feel any wear with my finger. Should I just take that cyl off and have it mic'd? Thanks in advance?
 
you mentioned the cheapest route/not to sink money, so, I mentioned get rings, and now replace'n gaskets/o-rings, why not dislodge the ring, clean the surface/groove from piston, get it to where the ring is usable, then if possible, install everything, and go from there.
Most likely, ovious fix and cheapest, would be to send to "sbt", get new motor for 800buks, being a 96", if you want it to be reliable...:cheers:
 
Piston rings are supposed to move with the piston. There is a small pin pressed into the ring groove to keep it in place.

What condition are the cylinder walls? Can you take a picture of the cylinder bores so we can see?
 
The cylinder walls are in great shape. I can still see the original cross hatch markings all the way around. I got the top ring off the piston, but the bottom ring is stuck like Chuck! I have the piston soaking now, so maybe it'll help loosen the ring. I'm only removing one cylinder and of course the base gasket tore. Can I just buy a new gasket and cut in half and use it for the front cylinder? (Its a 580 engine)
 
Basket case?.....

you mentioned the cheapest route/not to sink money, so, I mentioned get rings, and now replace'n gaskets/o-rings, why not dislodge the ring, clean the surface/groove from piston, get it to where the ring is usable, then if possible, install everything, and go from there.
Most likely, ovious fix and cheapest, would be to send to "sbt", get new motor for 800buks, being a 96", if you want it to be reliable...:cheers:

Sounds like we got a bit in common. I had one like that.

I got a Yamaha that had gone under, then they just sat it in the back yard. I did some motor work for them on their Boston Whaler and they gave it to me for payment. The carb and motor was froze up and I poured the PB Blaster to it and within 3 days, it broke loose.

Now, here's why I quoted timmyboy. I did not want to invest one penny in this thing till I knew I had a motor that would meet at least a few seasons. So, I used old gaskets, blue glue and what ever McGyver stuff I had to, just to get it back together and make it run.

I rode it in October and November. There is a noise coming from the rear crank bearing (heard with my stethoscope), so I think I got a flat spot......but, it runs.

Now, with good compression (I should say o.k., not really good), I'm going to take the motor back down and look at the suspect bearing and go ahead and replace all the gaskets and see if it'll make this next coming season.

The point is.............you don't have to replace that gasket. It's a 2 stroke. It doesn't have a water jacket at the bottom of the head. It comes in at the side. So, try and trim it up and do like timmyboy said, try and draw that ring out and clean up the grooves, then slap all that stuff back together.

Once you think you got something that's gonna be worth puttin money into, you can estimate how much and what it is your gonna need, then make an informed decision on whether it's worth it or not..........

Is this the right way to do this?........... No. But I did it anyway.:cheers:
 
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