Piston

[Anonymous]

I just took apart my engine and realized that i need the noise was due to a severly warn piston. Does anyone know where I can get a stock piston for a 1983 gs750e? I called the dealer and they want $90 CAD for it, and no where else that I can find can get me one. And on top of that they are backordered to Japan. Thanks!!

[lhanscom]

You may want to consider going with the 816 kit, obviously you would need to do all the cylenders, but the payoff would be good. If I remember correctly it would cost around $500 to get the kit and boring done.

As for a single piston, ebay is about the only place I can think of, unless somebody has one kicking around here somewhere.

[focus frenzy]

As for a single piston, ebay is about the only place I can think of, unless somebody has one kicking around here somewhere.

there is a good chance some one here has a couple laying around, I have a set of stock 1000 pistons with little wear.
my question is, what caused the one piston to fail?

[Anonymous]

I just took apart my engine and realized that i need the noise was due to a severly warn piston.

I would be measuring the bores and other pistons before replacing only one on a well used engine. Wiseco has sets for very reasonable prices and then you would be starting fresh with a zero time top end at least. It seems a false economy to me to try to only replace one piston. If it was a new motor and you had a failure, then maybe a new piston would be the ticket, but that is not your situation here.

Mark

[Anonymous]

Well, I did measure all the other pistons/cylinders and they are all well within the wear limits, and they all appear to be in great shape. I jsut dont know why this one failed the way it did. It was in cylinder 3. COuld this be due to insuffecient cooling? Any other places I should check as the possible culprit for this? The cylinder wall is in good shape, its just the piston that seems to be the problem.

[redliner1973]

What exactly, was wrong with the piston? You say, 'warn', Usually a cyl will wear harder and more than a piston.........

[Anonymous]

The noise I heard was from the piston slapping side to side. When Measuring the cylinder wall its the same as the rest, and when I put a piston from another cylinder into the one where the warn piston came out, its mint. The piston is just scored and warn, well beyond the service limit and enough to slop side to side in the cylinder. Does that help any?>

[daveo]

The noise I heard was from the piston slapping side to side. When Measuring the cylinder wall its the same as the rest, and when I put a piston from another cylinder into the one where the warn piston came out, its mint. The piston is just scored and warn, well beyond the service limit and enough to slop side to side in the cylinder. Does that help any?>

You need to check that connecting rod for sure, big and small ends, was the piston wallowed out at the wristpin bosses? How was the fit of the wristpin through the connecting rod small end? Was there a ring broken also? You may need to replace the connecting rod and bearing, wristpin and piston at the least, I 'think' that engine still has a changeable plain shell bearing bottom end...as opposed to a roller bearing which are press fit..not positive though

[SqDancerLynn1]

I have some pistons from an 81/750 They made changes to the 83 motor so I don't know if they will fit?

[lhanscom]

I would be concerned replacing a single piston with anything other then exactly what came out of it originally. Just thinking any minute differences, like weight, or piston top design, or... could cause vibration, and accelerate wear.

but maybe I'm just paranoid.

[Anonymous]

I did notoce that the wrist pin in the piston was a little more snuig the thes other ones. The other ones I can spin freely in the piston with my fingers where as the piston that is worn, the wrist pin isnt easily moved.. Could this play a part in anything?

[daveo]

I would be concerned replacing a single piston with anything other then exactly what came out of it originally. Just thinking any minute differences, like weight, or piston top design, or... could cause vibration, and accelerate wear.

but maybe I'm just paranoid.

You're right, it would be better to overbore and replace them all together, and yes the the #3 problems could have started with the wristpin being too tight, as it heats up it tightens also, causing the skirts to scuff, sometimes the retaining clips can come out too. Earlier this year I had one, on another brand bike, where they were too tight from the factory and actually broke the piston,a crack through the wristpin bosses with a chunk gone at the crown, when it siezed. That connecting rod needs special inspection.

[Anonymous]

ALright. THanks very much, I will let you know what else I find out. Also, what kind of plugs should I be running in the bike? Its a 83gs750e. Thanks!