Piston Starting to Go? Video

[trestlecreek]

Not every two stroke needs pistons around 2500 miles. I bought 4 Polaris 550 fans out of West Yellowstone a few years ago. They averaged 5000 miles on them when I picked them up. Everyone of them have over 10,000 miles now, all stock original pistons, clutches, ect.... Wish they could get that out of these 800's. Oh Well, just my 2 cents.

 

[cpittsy]

2400 miles on a 2 stroke snowmobile engine !

not defending polaris but any 2 stroke wants pistons by 2400
glad you got her back up quick

My 1990's Yamaha Triple has 9K on it and I fully expect it to go another 9K.

Like most things in this country, they dont make em like they used to.

 

[rmscustom]

Not every two stroke needs pistons around 2500 miles. I bought 4 Polaris 550 fans out of West Yellowstone a few years ago. They averaged 5000 miles on them when I picked them up. Everyone of them have over 10,000 miles now, all stock original pistons, clutches, ect.... Wish they could get that out of these 800's. Oh Well, just my 2 cents.

My 1990's Yamaha Triple has 9K on it and I fully expect it to go another 9K.

Like most things in this country, they dont make em like they used to.

You guys can have your 550 fan power and your triple weight... I'll put pistons in a high performance lightweight motor every year.

 

[GoBigParts]

Not every two stroke needs pistons around 2500 miles. I bought 4 Polaris 550 fans out of West Yellowstone a few years ago. They averaged 5000 miles on them when I picked them up. Everyone of them have over 10,000 miles now, all stock original pistons, clutches, ect.... Wish they could get that out of these 800's. Oh Well, just my 2 cents.

My 08 IQ RMK 600 has almost 8000 miles on the stock pistons. I am rebuilding it this year but the darn thing still runs great..

I will try to get around to getting some pictures of those 800 slugs and rings.

 

[gman086]

The GENERAL rule of thumb is to replace 2 stroke pistons every 2-3,000 miles for mountain riding and 3-4,000 miles for flatlander riding. Stock motors with NO mods can typically go longer (much longer for smaller bore motors) while heavily modded bigger bore sleds need replacement sooner.
SO... none of the comments I've seen so far are the least bit surprising.

Have FUN!

G MAN

 

[GoBigParts]

OK, I finally got some pictures taken of my old worn out pistons. The pistons don't look too bad. The ring groove is starting to open up a bit on the exhaust side. My dealer showed me other pistons in the shop that opened up bad there to the point that the top broke right off from the groove up on the exhuast side.

The rings looked flaked pretty bad. Remember 2400 plus miles of riding midwest trails and off trail, deep snow in the U.P., the Snowy mountain Range, and Island Park ID area.

 

[spencer]

OK, I finally got some pictures taken of my old worn out pistons. The pistons don't look too bad. The ring groove is starting to open up a bit on the exhaust side. My dealer showed me other pistons in the shop that opened up bad there to the point that the top broke right off from the groove up on the exhuast side.

The rings looked flaked pretty bad. Remember 2400 plus miles of riding midwest trails and off trail, deep snow in the U.P., the Snowy mountain Range, and Island Park ID area.

Have 2011, piston and rings nearly same condition except no bad rub spots, noted power loss at 2100 miles. All Mountian riding ( mostly Baker ) added 2.5 OZ to each tank of fuel only used Non ethanol fuel.

 

[spencer]

I turned them so all could see port and exhaust sides, is the brown and black baked in stains from the 2 stroke oil ?

 

[rmscustom]

I turned them so all could see port and exhaust sides, is the brown and black baked in stains from the 2 stroke oil ?

That's all your power blowing past the rings.

 

[GoBigParts]

I could feel my power loss. I probably lost 200 RPM all together.

 

[SnotNose]

Good RKTek article on ring pistons

http://www.2strokeheads.com/tech6.htm

 

[TRS]

http://www.2strokeheads.com/tech6.htm

Interesting article on the flaking rings and piston problems. I do believe we can relate.

 

[QuickSwitch]

I could feel my power loss. I probably lost 200 RPM all together.

I experienced the same thing last winter , drop of 200 to 300 rpm , compression fell off to below 120 psi per cylinder.
I finally scuffed the PTO side piston at 5200 miles .
New motor installed .
I will keep an eye on compression readings and rpms on this new motor .
Pistons are cheap maintenance , most likely change them at 2500 miles .

 

[GoBigParts]

I experienced the same thing last winter , drop of 200 to 300 rpm , compression fell off to below 120 psi per cylinder.
I finally scuffed the PTO side piston at 5200 miles .
New motor installed .
I will keep an eye on compression readings and rpms on this new motor .
Pistons are cheap maintenance , most likely change them at 2500 miles .

You got 5200 out of the original motor. Pretty good. Yeah mine always ran strong with the stockers. Just had warranty but the stockers back in. I feel the sled ran really strong up to about 2400 so for safety I would at lead take a look at them by then. I have still not heard of aftermarket pistons going way beyond 2400 but I'm sure people just have not had them long enough to log those kinds of miles.