Burned Piston '95 SLX

[atlantis]

I've burned a hole in the top of the #2 piston on my '95 polaris 750 SLX. Can I just replace the piston,rings,etc...Everything else looks fine. What else do I need to look for or do before hitting the water? Thanks

[Bryan Glynn]

If the hole has burned all the way through, you really need to also replace the crank. The molten aluminum bonds itself with your crank bearings, and they they are shot. You could spend a few hundred bucks putting half a new engine in there, just to have the other half blow in a couple hours after firing it back up. I've seen it tried way too many times, and many on here can testify to that.

If it's not all the way through yet, and the cylinder isn't too badly scored, you may be able to rehone and put a same-size piston and ring set in, yes. You won't know until you go to hone it, if the damage is too severe or not.

[Nap]

I have a 1993 650 sl with a hole in #1,Scored bad ect.I bought a standard piston 1 ring,I salvaged 1 ring because of the 40$ per ring price,and honed cilinder.I have ran it about 20 times.It runs great.Compression 105 lbs per cyl.It seems to work fine.I didn't even have to pull enging out of ski.

[atlantis]

Thanks. I'm struggling with the decision to just risk replacing the piston (the cylinder looks fine) and see if that works. If it doesn't, look at a rebuilt motor (there's no telling what it will be next time). I bought this boat used and it has been troublesome, but boy will it move.
It's hard to justify spending a lot of money on an old boat that is only worth $1200-1800. I have a '94 750 SL and have never had any trouble with it.

[Madhouse]

Verify that the sleeve is not below the surface of the deck. If it is, a good indication (other than the piston) would be the oring is burned as well.

mark c.

[tomsl750]

Atlantis, Don't even try putting another piston in. You are just wasting your money. If you do your crank will soon fail. You can ask many others around here. Jalaycock can vouch for this one as well. Also as a note: a healthy engine should have a compression in the neighborhood of 120-125 on the 750's. With that much aluminum down there, you are guaranteed to have to replace a crank. Bryan knows his stuff. I'm sure he gets paid well and will continue to even if you don't buy an engine from him. He would not falsify advise for the sake of another sale. He is well above that.