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1999 GTX Limited piston change

changetires

Active Member
Messages
9
Water Crafts
1999 GSX RFI
Question is can you change out a burnt piston on this 951 engine while the engine is still in the ski? Oil tank developed a leak while at the launch not at speed. Running a compression check this evening to see.
 

mikidymac

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1996 XP
1996 HX
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You can but if you lost oil you need to bore the cylinders and have new oversized pistons installed in both cylinders.

It will not be just replace one stock piston job and hope it runs.
 

changetires

Active Member
Messages
9
Water Crafts
1999 GSX RFI
thats what I was thinking. I mean you will have them both apart anyway. Thanks for the reply..
 

etemplet

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2,756
Location
Louisiana
Water Crafts
1996 SPI, 1996 GTX, 1997 GTX
I did a top end on a 1998 GTX Limited with the engine in place last summer. It is a toss up to whether or not I'd do it that way again. It is very tight getting the studs out. All the studs will have to be unscrewed all the way in order to remove the cylinder. I used the 2 nut method to remove the studs that did not come out with loosening the nut. Check the connecting rod bearings on the crankshaft real close. Good Luck !!98 GTX 951 Piston (1).JPG
 

changetires

Active Member
Messages
9
Water Crafts
1999 GSX RFI
What’s the chances that if I put some premix ion and prime it up, put a little 2 stroke down the plug holes and fire it off that the tapping will clear up?
 

mikidymac

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2003 GTI
2001 XP
1996 XP
1996 HX
1991 Superjet
2001 Superjet
2-strokes don't work that way. 0.0000% chance it will work.
You have a damaged piston and cylinder so the only way to fix it is to bore both cylinders and have oversized new pistons fitted.

If you keep trying to run it the debris will get into the crank bearings and destroy it too if it hasn't already.
 

changetires

Active Member
Messages
9
Water Crafts
1999 GSX RFI
Yeah I tried it out and it is definitely 0.0000000% chance.
Found out the PO did not tell me they blocked off the oil pump and used mixed gas. That would have been good information. So it appears I will be pulling it down and see how many mm will clean it up.
 

etemplet

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2,756
Location
Louisiana
Water Crafts
1996 SPI, 1996 GTX, 1997 GTX
Well, tongue in cheek.... there is a 100% chance the tapping will subside as soon as the engine locks up. :D :D On a more serious note, you're gonna need a crankshaft if the ski ran without oil. Damage is already done. If you are gonna roll the dice on that make sure you check the connecting rod journals on the crankshaft. Check them visually and for slack/clearance. I'm a condition based maintenance and repair guy but a no oil failure is deadly to the crank. Good luck whatever you decide.
 

changetires

Active Member
Messages
9
Water Crafts
1999 GSX RFI
Luckily we were not running it at speed. Just idling at the ramp. Friend of mine who owns a machine shop said he could clean up the cylinders for $80. I thinking about rolling the dice and doing it in the ski
 

etemplet

Premium Member
Premium Member
Messages
2,756
Location
Louisiana
Water Crafts
1996 SPI, 1996 GTX, 1997 GTX
Yeah I tried it out and it is definitely 0.0000000% chance.
Found out the PO did not tell me they blocked off the oil pump and used mixed gas. That would have been good information. So it appears I will be pulling it down and see how many mm will clean it up.
Bummer..... on the oil. I know guys that run the oil pump AND 50:1 mix and did that for years. :)
 

DanSquires

Well-Known Member
Messages
366
Location
Blue Springs, MO
Water Crafts
More skis than brains.
Luckily we were not running it at speed. Just idling at the ramp. Friend of mine who owns a machine shop said he could clean up the cylinders for $80. I thinking about rolling the dice and doing it in the ski
just pull the engine. by the time you do all of the work to pull the top end with the engine in the ski, you'd have had the engine out for hours.
 

changetires

Active Member
Messages
9
Water Crafts
1999 GSX RFI
Even if I have never pulled ski engine before? It’s a real bummer cause the ski was idling like a champ but it is what it is.
 

DanSquires

Well-Known Member
Messages
366
Location
Blue Springs, MO
Water Crafts
More skis than brains.
Even if I have never pulled ski engine before? It’s a real bummer cause the ski was idling like a champ but it is what it is.
Yes.
By the time you pull everything you need to pull the top end, you're a dozen or so easily accessible nuts and bolts from having the whole engine out.
 

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