I am going to replace the upper needle bearing. Everything else seems pretty tight. Is it ok to use synthetic to break in the new piston? I know with cars, synthetic is a no-no during break in...

I had checked the injector per my manual, and the throttle cable is just right and it appears to be oiling just fine.

I decided I am going to send the cylinder off to RCR instead of taking it to a local place. I just don't know how much I can trust a local place. This way, I will just have him bore it and order a wiseco to match it and get it all back at one time. Just gotta wait for him to get back to me [img]i/expressions/face-icon-small-smile.gif[/img]

-Chris

 

I would not have a problem using a synthetic to break in, but that is one of those topics where everyone will have a different opinion and will argue til blue in the face.

 

Well, I have the cylinder all boxed up. Decided to send it out to RCR so I know it's done right [img]i/expressions/face-icon-small-wink.gif[/img]

Anyone know his usual turnaround time? For something simple like boring a cylinder?

Thanks,
-Chris

 

WELL I HOPE I'AM NOT TO LATE TO REPLY!! I HAD THE SAME PROBLEM WITH MY 98 300 XPLORER. I TALKED TO DEALERS THAT SAID MINE OVER HEATED. THE SKIRT BROKE OFF THE BOTTOM OF THE PISTON.IT LOOKED LIKE THE HEAD GASKET WAS LEAKING, THE DEALER SAID THAT WOULD CAUSE IT TO OVERHEAT. SO I HAD THE CYLINDER BORED .020 OVER , NEW WISCO PISTON AND NEW GASKETS. ABOUT $150.00. CLEANED IT ALL UP PUT IT BACK TOGETHER, RAN TWO TANKS OF GAS THOUGH IT, DID THE SAME THING, OVERHEATED. THIS TIME I TOOK IT TO SOMEBODY WHO KNEW MORE ABOUT IT. HE TOOK THE MOTOR COMPLETELY APART, FOUND BAD CRANK SEALS, WHICH CAUSE IT TO OVERHEAT. HE ALSO FOUND THAT THE CRANK BEARINGS WERE BAD. ANOTHER $500.00. TAKE THE TIME AND THE MONEY TO DO IT RIGHT THE FIRST TIME. HOPE THIS HELPS!!

1998 300 XPLORER (JUST REBUILT)
2001 400 XPLORER

 

RCR does all his boring on Wednesdays, so maybe it could get done this coming wed. if you get it to him. I dont know though.

He will get back to you if you left him a message I am sure, he has great service.

 

Exploreratver: I did check out the bottom end. The rod bearing is in great shape, nothing was leaking past any of the gaskets either.
I also do not believe that the ATV truly overheated. When the machine stopped, the fan kicked on, but then kicked off, which means it was right at the temperature threshold. I believe mine truly was part failure (piston ring). I have another friend that is going to come over when I put it together, he knows more about them than me, so I will ask him to check everything out again to make sure I am right....

It would suck to have to do this again [img]i/expressions/face-icon-small-wink.gif[/img]

Troyer23J: Yes, I called RCR and they told me they do boring on Wednesdays. I should have shipped it out overnight, unfortunately, it got there Thursday AM [img]i/expressions/face-icon-small-wink.gif[/img]
Oh well, one week shouldn't kill me.

-Chris

 

why it is apart go ahead and get the head milled about 15 to 20 for a little more response my machine shop charged 15 dollars to do this when I had mine bored

 

The stock polaris pistons are famous for breakage.

 

Whitedog: That's the funny part, the piston itself appears fine (aside from the scratching), only the ring itself broke. The ring land appears unharmed.

RCR got my cylinder yesterday, so it should be bored out this coming wednesday. I got my cometic gasket set and new upper needle bearing today. So I should be all set once the package arrives [img]i/expressions/face-icon-small-smile.gif[/img]


-Chris

 

Well, RCR bored out the cylinder last night.
Turns out that it had already been bored 20 over previously. So it is not at 40 over [img]i/expressions/face-icon-small-wink.gif[/img]

Seeing as how it is now 40 over, will the oil injection still be adequete? I'd prefer to keep it if possible, but will switch over to premix if necessary.

-Chris