Wana see a fancy looking piston?

[B0000M]

my jetski made an unkind noise yesterday, heres the results...

the last piston shows both pistons. runs twin carbs with a big mixing section between them so i dont see how its jetting....

top bearings on the fucked one were totally rooted.

[RM125king]

Looks to me something has fallen in there and has been bouncing between the head and piston. Are the piston rings still complete?

Its that or a serious case of detonation/pinging. What was the compression? Anything over 180 PSI and you should be using AV gas.

[B0000M]

Looks to me something has fallen in there and has been bouncing between the head and piston. Are the piston rings still complete?

Its that or a serious case of detonation/pinging. What was the compression? Anything over 180 PSI and you should be using AV gas.

well i havnt found the casing for the top end bearing on that cylinder.... the other one fell apart as i took it out- quite likely it was them.

compression, unsure, but when i did pistons and rings on my old 650 i got 185psi on each cylinder, so i presume this is less as ive had it a while and not done any work to it

[Crasherfromwayback]

Has gone through it mate! I'm guessing bits of big end thrust washer or needles from the big end...or if you're saying the gudgeon pin brg is rooted...bits from that. Either way...you're gonna have to split the cases and check the crank.

[RM125king]

Yeah i would say it was the bearing cages bouncing around in the top.

Try and find an after market head or you can use that one again with a bit of a clean up. Get a couple of new pistons and bearings and your away again for another 10 years.

[Crasherfromwayback]

well i havnt found the casing for the top end bearing on that cylinder.... the other one fell apart as i took it out- quite likely it was them.

You've just answered my question. Major melt down.

[Crasherfromwayback]

Yeah i would say it was the bearing cages bouncing around in the top.

Try and find an after market head or you can get that one welded up and machined. Get a couple of new pistons and bearings and your away again for another 10 years.

Incorrect. Crank cases split...crank rebuild. That shit that's mashed the piston and head has also gone through the mains/big ends...and that's if it's not the big ends in the first place.

Total rebuild.

[B0000M]

yeah, thats the plan, ive got a mate whos up for repairing the head, the cylinder definately needs a hone or a re sleeve, not sure which yet, im not expert on whats good enough and whats not on that topic.

note in one of the pics the broken skirt - that bit is a concern...

[RM125king]

Yeah he will def have to split the cases but if the pieces got to the head they must be pretty small. Theres still a chance the crank might be alright. Will still def have to pull apart and check.

[RM125king]

Yeah i didnt notice that. Your up for a new cylinder. Fark mate it might be cheaper/easier to source a second hand motor or Write the ski off.

[Crasherfromwayback]

yeah, thats the plan, ive got a mate whos up for repairing the head, the cylinder definately needs a hone or a re sleeve, not sure which yet, im not expert on whats good enough and whats not on that topic.

note in one of the pics the broken skirt - that bit is a concern...

Mate...the whole thing is a 'concern'. I'm totally guessing here...but I think the ski has been put away without having being 'flushed' properly at some stage. As I'm sure you know...the exhaust systems are full of water. If you put the ski away after riding it...and don't run the ski to get the water out of the exhaust...the water sloshes into the crankcase back through the exhaust port and then rusts the crank and the mains/big ends.

The mains/big ends then fly apart and mash your piston/head and barrels.

Major rebuild. Then ALWAYS flush the ski when you're done riding it.

[Crasherfromwayback]

Yeah he will def have to split the cases but if the pieces got to the head they must be pretty small. Theres still a chance the crank might be alright. Will still def have to pull apart and check.

Not true sorry mate. If you're familiar with how two strokes work...you'll know that that shit has gone through the big ends/mains. She's over.

[B0000M]

Mate...the whole thing is a 'concern'. I'm totally guessing here...but I think the ski has been put away without having being 'flushed' properly at some stage. As I'm sure you know...the exhaust systems are full of water. If you put the ski away after riding it...and don't run the ski to get the water out of the exhaust...the water sloshes into the crankcase back through the exhaust port and then rusts the crank and the mains/big ends.

The mains/big ends then fly apart and mash your piston/head and barrels.

Major rebuild. Then ALWAYS flush the ski when you're done riding it.

na, you've guessed completely wronge. always flushed for about 5 minutes after riding, im religious about that, and other cleaning for that matter, then run till water stops coming out the exaust, also make a habit of pulling the bottom end bung cord before putting away just in case. the bottom end and mains feel perfect, so im not going to point the finger in that direction at all.

[RM125king]

Not true sorry mate. If you're familiar with how two strokes work...you'll know that that shit has gone through the big ends/mains. She's over.

I have seen a few let go and i havent seen one yet to take out the crank and cases.

Split the cases mate and check it out. Put some pics of what you find.

Cheers

[Crasherfromwayback]

na, you've guessed completely wronge. always flushed for about 5 minutes after riding, im religious about that, and other cleaning for that matter, then run till water stops coming out the exaust, also make a habit of pulling the bottom end bung cord before putting away just in case. the bottom end and mains feel perfect, so im not going to point the finger in that direction at all.

Well good to see you get rid of the water mate. But if you're missing a little end brg case and it's needles...you're gonna have to pull the crank out. If you don't...and you simply fit new pistons and s/e brgs...you'll be doing it all over again real soon.