1999 GTX Limited piston change

Note: This site contains eBay affiliate links for which SeaDooForum.com may be compensated
Status
Not open for further replies.

changetires

Active Member
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.
 
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.
 
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
 
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?
 
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.
 
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.
 
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.
 
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
 
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. :)
 
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.
 
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.
 
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.
 
Update on the 951
Had the cylinders bored from a 1.0 to 1.5....
Got a new top end kit from SBT.....
Got it together today.....
Had to use a large hose clamp to squeeze the rings in while I slid the cylinders down, installed the long bolts before putting the cylinders on and kept them from sliding down by using rubber bands to hold them together...
Finally got it after the 5th attempt.... definitely had to take my time. Should have it river ready by Monday
 
If you haven’t already make sure you rebuild the carbs and fuel system before you even think about starting it.
 
Rebuilt the carbs and reinstalled before putting pistons on the rods.....much easier than working around that exhaust pipe
 
951 is up and idling today....had to wait for new carb gaskets to come in
Taking it to the river tomorrow and see how it goes for a little break in period
 
Yes indeed. Run it for 5 minutes then pull in and check temps on the engine and for leaks. I ride with the seat off for the first ride. I fondle the cylinders and exhaust making sure there are no hot spots. . :) :) Good Luck !!
 
Status
Not open for further replies.
Back
Top