Top end - replace 1 piston and cylinder only? - Snowmobile Forum: Your #1 Snowmobile Forum

losian79 · 03-07-2012, 02:46 PM

Getting work done on my sled and the dealer suggested replacing only 1 of the two cylinders - just the one the had a problem. The other one was burning nice...from what I can tell, and from what they say.

I thought it was typical to replace both. Will having replaced only one make more issues if one cylinder has more compression than the other?

Also, curious where to find out what the compression should be on Polaris sled. (2009 Dragon 800 RMK).

ridegreen · 03-07-2012, 05:46 PM

I personally would replace both so it would have more equal wear if the compression is greater then the other. Or replace them both for a pice of mind.

wastedincome · 03-07-2012, 06:20 PM

I just cant see replacing only ONE side, I'd do BOTH, imo

**smallengineguy** · 03-08-2012, 03:51 AM

If they had to overbore it more than .020, then do both sides.

Phaze · 03-08-2012, 09:25 AM

I'm jumping on the "both" bandwagon. Just like you wouldn't replace 1 plug that went bad..... I'm big on piece of mind.......

wastedincome · 03-08-2012, 09:44 AM

^^lol, I like the spark plug reference.....

**BC_Dan** · 03-08-2012, 04:07 PM

How many miles? What was the cause of the failure? What's the compression on the good cylinder?

It is certainly going to be cheaper to just fix the broken side, but if the engine has a bunch of miles on it, go for both, or at least both pistons. The 800 has lined cylinders and if the cylinder is within spec I would not hesitate to use it. I have seen nikasil lined cylinders with 4000 miles on them that still retained the factory cross-hatching, there was so little wear.

The end result should be two cylinders that are fairly equal in compression. The closer to equal the better, but if they are within 10% of each other, that would meet OEM specs.

Let your pocketbook be your guide

losian79 · 04-07-2012, 01:25 AM

Thanks for all the advice. Ended up getting 2 new cylinders and 2 new pistons, subsidized from the dealer. They had plugged in the wire for my 2009 Polaris Dragon that is for non-ethanol fuel only. Wish they would have told me so I could have ridden in March.

Gaylord Huta · 05-01-2012, 07:45 AM

I've done just one before and never had a problem, but 90% of the time I will do both.

Gaylord Huta · 05-01-2012, 07:46 AM

Was that just they're excuse why your sled went down? or do they actually know that?

jordandakota · 05-01-2012, 10:59 AM

If it's an 800, no wonder it blew. From what I understand, the 09 Dragon 800 was the WORST for engine issues.

Renagade · 05-01-2012, 11:25 AM

Quote:

Originally Posted by jordandakota

If it's an 800, no wonder it blew. From what I understand, the 09 Dragon 800 was the WORST for engine issues.

i heard that also, all poo guys round here have
600's and 700's.

id prolly replace both jugs, just for peace of mind insurance.

JD8345RT · 05-01-2012, 03:50 PM

I've got a buddy who burned up a piston on his Z440. Got the problem cylinder honed and replated (not bored) and going to throw a new piston in it. Told him compression difference might be an issue, hope they're within 10% when it's all said and done!

The '09 was the worst, but the '10 Dragon 800 was also poorly mapped.

**kccats** · 05-01-2012, 05:51 PM

You wouldn't need to replace the cyl just have them replated! The odds are that US Chrome in Wi did them orriginally! And if the enrichment was the issue by all means replace both! But why would one look good and the other burn? I would look deeper something aint right!

losian79 · 05-02-2012, 03:16 AM

We had 87 octane in it (fine according the manual). But they dealership left the wire plugged in that requires 91 octane with no ethanol. That was most certainly the problem. This wire is not described in the manual, but Polaris had some print out that they had posted on their door that clearly stated this wire needed to be unplugged.

Polaris also updated the pistons since their recall on this machine so getting both done ensured I had the same pistons.

**kccats** · 05-02-2012, 06:52 AM

But if this IS the problem with the burn down, then BOTH pistons would have gone! Keep looking!

Renagade · 05-02-2012, 08:51 AM

Quote:

Originally Posted by kccats

But if this IS the problem with the burn down, then BOTH pistons would have gone! Keep looking!

id have to agree that there would be dammage
to both cylinders if wire was the problem.
gotta be something else id think?

Gaylord Huta · 05-02-2012, 09:04 AM

Quote:

Originally Posted by Renagade

id have to agree that there would be dammage
to both cylinders if wire was the problem.
gotta be something else id think?

agreed. did they give you your old pistons back or did they toss them?

I think the dealer is giving you a band-aid and you'll be back next year for more pistons.

Renagade · 05-02-2012, 09:11 AM

weird. you would think, since the season sucked,
that the dealer would be trying to upsell??

not that the band-aid theory couldnt be true.
stranger things have happened i guess.

**kccats** · 05-02-2012, 09:29 PM

So have you heard thats its time for an upgrade?