advice for new pistons??? Reliable... awesome.... CRAZY!!!

thstorms

thstorms

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Jan 5, 2010
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Location
49071 MI
have to rebuild my 600 twin that I got hozed on!!!! just looking for a little help picking new pistons as its my first sled!!!

I'm a dirt bike and jetski guy, I have always used Weisco pistons..... they're lighter and seem to treat me right!

I have heard a few opinions about OEM and AM pistons...... please share your experience!!!

Thanks for the replies in advance!!! any info is appreciated!!!!
 
from what I understand,go with OEM..they are tough pistons.When I do a rebuild on my sled motors,I`ll go OEM for sure.Weisco pistons I`d be afraid to use.Heard some horror stories with them in sled motors,others like them.Stick with OEM and you can`t go wrong.
 
My Father has a mill and lathe in his basement I can bore the cylinders to the perfect size for any poston, I just need to know what is the most reliable and what the tolerence is!!!!

this goes for anyone who needs awesome work done at a hobbiest price!!! pay for the electric it takes to run the shop, my pop is in heaven when he's tinkering in his work shop!!! doesn't have fancy cnc machines but if you know exactly what you want he is more than capable and still does it for fun!!!!!!! a rare find when you consider some of these shops rates!!!!!!!
 
I have a new set of wiseco slugs for your sled, I bought them to rebuild with but went another direction. Let me know if interested. I am just outside of grand rapids.
 
I put Wiseco pistons in my 600 twin last year and haven't had any problem with them I had to have my cylinders redone also so I had Millenium tech. redo my cylinders and they fitted my piston to the bore for me I check and end gap on the rings and the sled runs fine. The only thing I have heard about Wiseco pistons is that the rings are not as thick as oem. If you need anymore help with torque specs or tolerances let me know I could maybe send you that info out of manual.
 
tolerances would help greatly!!! The cylinders I have are good, a couple very minor scratches that I can barely feel with my fingernail.....

If you have the specs for how tight pistons are supposed to be that would help.

I might need a new Head, if so what is the best head??? and does that change what pistons I should use???
 
I have used wiseco pistons on many toys. I've never had a problem using wisecos and actually since they are lighter, they make more power.

You just need to allow the sled to warm up completely or you can run into cold seizures a little easier than stock ones. Not a biggie IMHO.

I would PM ottawaair and buy those pistons.

As far as tolerances, have you looked on wiseco's site? You need to do some measuring, but if the jugs are scored and need more than a light hone, then I would send them off to get replated/ or exchanged.

As far as the head, you won't really find anything but stock. I would concentrate on getting it running and maybe dot eh reed stopper mod, the spacer mod and shave the new head gasket while you are rebuilding it.

Mine is stock and goes very nicely. It is a 97 hp machine, doing those mods will get you a little over 100hp total and you should be happy. it does suck that you got hosed with a bum machine. is there any recourse, or did you buy it private party as is?

I recall one kawasaki X2 jet ski I bought used from a dealer. It was a limited class race ski and it had piston issues that were discovered about a week after I bought it.
I made the dealer fix it.
 
thstorms said:
tolerances would help greatly!!! The cylinders I have are good, a couple very minor scratches that I can barely feel with my fingernail.....

If you have the specs for how tight pistons are supposed to be that would help.
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The bores are Nikasil plated, so unless you send em out to get re-plated ($190 per hole) you wont be able to adjust tolerances to your pistons, take a bore mic and check em out to the Yamaha tech specs and run OEM pistons...
 
i have not done a search, but for stock sled i would use cast oem, now if you know who makes them for yamaha, you could buy them from them, like alot use art pistons way cheaper to buy from like dennis kurk then dealer, wiseco is more of a race piston, its forged it expands differently, and if you race, you rebuild more often and are looking for any little hp gain you can get for short runs just my 2 cents
 
I have run Wiseco's in many different 2stroke dirt bikes and my current sled, never have I had any issues with them. Ride it like you stole it...
 
horkn said:
I have used wiseco pistons on many toys. I've never had a problem using wisecos and actually since they are lighter, they make more power.

You just need to allow the sled to warm up completely or you can run into cold seizures a little easier than stock ones. Not a biggie IMHO.

I would PM ottawaair and buy those pistons.

As far as tolerances, have you looked on wiseco's site? You need to do some measuring, but if the jugs are scored and need more than a light hone, then I would send them off to get replated/ or exchanged.

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X2 - warm up is critical with Wiseco's. Just make sure you're the first one out of the restuarant while everyone else is gearing up.

Over 6000 trouble free miles with .020" oversized Wiseco's in my 607 monoblock Polaris.

Not disagreeing with others that recommend OEM. But IMO, Wiseco's get a bad rap due to folks not following warm up recommendations or tolerance specs. IMO, it is a better piston but not as tolerant of improper warm up.
 
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