Dealed called...no burndown...broken exhaust valve!

[fredster]

I'm the lucky guy with the Pol 600 that appeared to have a burndown last weekend. Dealer just called. No burndown - mag side exhaust valve broke and took out the piston. The pieces of aluminum that I found on the spark plug came from the chunk that was bouncing around in the combustion chamber. This also explains why I could not rotate the engine, there was a piece wedged in place.

Service mgr said the carbs are clean (good!) and the other piston looks OK, but is at the 'service limit' so both pistons will be replaced. The cylinder and head wasn't harmed which is good (the cylinders are really pricey, too!).

I did pull the valves in the fall and gently cleaned them. They didn't have much residue on them and they were only out of the sled for 10 minutes. I didn't drop either one. Really strange. I have pulled the values on our older Liberty 600 many a time and they are fine at 5000 miles. The dealer said they have never seen a broken exhaust value on a 600. I have read about Pol 800' s having that problem several years ago, but only the 800. Plus this engine only has 2500 miles. It's a 2005 so it's not that old.

The bad news, this is even more expensive than a burndown! Two exhaust values plus all the normal rebuild goodies (pistons, rings, seals, labor) adds up pretty quickly. The good news is the engine will be fresh (and hopefully ready to go).

Perhaps a small moral victory knowing that a lack of maintenance didn't cause the problem.....but I'm still staying away from "Iso Al" in the future!

 

[michaeladams]

when i took mine out to clean it looks like you could put them in upside down and that wouldn't be good.looks like piston could hit them if that happened.good thing i took them out 1 at a time cause the way they look like they would go back toghether is the wrong way.

 

[indy_500]

canuck600 on here put his powervalve in backwards and blew it up, am i right canuck600? please correct me if i'm wrong

 

[willey]

You can't put the valves in upside down. They don't slide in all the way.

 

[fredster]

On both Pol 600's I have, pretty sure the valves will only go in one way. Of course, I'm a little short on credibilty right now!

 

[xcsp]

Fredster, did the valve actually break into pieces or did the "stop" on the valve blade break off?

I had a '01 500 XC that the stop broke allowing the valve to contact the piston ever so lightly, no serious damage & was under warranty at the time.

 

[fredster]

I don't have the details yet; service manager said "broken exhaust valve". I do know that I could not turn the engine over after it shut off, so it appeared the entire valve or a large portion had moved into the combustion chamber and was blocking the piston's travel.

I asked for the parts and will talke to the mechanic when I pick it up next week.

 

[toddspolaris]

I can hardley believe that the other piston is at its service limit with that low of milage. Why not rebuild the side with the problem and save some money. I have some buddies with 600 pol. with over ten thousand miles and motor has never been opened, and it still has great compression and runs strong.

 

[fredster]

I agree, and am surprised, too. My 2000 600 triple went 8200 miles on the original pistons and rings. I'll be talking to the dealer again -

 

[jebjk1]

I broke a valve in a Poo 600 once too. Luckly it didn't hurt the motor at all. It was in the fall, before the season... I was getting it ready for the winter and thought I should clean the valves. Took the two bolts out, pulled on the vavle body, and the entire blade stayed in the motor. It had a clean break on the shaft of the blade. No idea how long it was like that either.

 

[xcr440]

I guess my thought on replacing both pistons (besides the cost) is obvious. Your in there, why not do the whole thing and have the piece of mind that you have a NEW motor, not just a new half of the motor.

Get your old parts back, sell the good ones, and let someone else take the chance of replacing just one piston/ring combination.

 

[02edgehead]

i m surprized the dealer has never heard of a valve breaking in a 600 before. mine broke at about 8000 miles a hit the top edge of the piston then got lodged up so i was lucky it didnt leave me stranded. i think originals werent stainless but the replacements are. maybe because of breakage??? i replaced both pistons also seeing as in how it was apart only because i wanted matching pistons. i went with wiseco pistons. i think i got better performance out of them than the oems

 

[fredster]

After talking to the dealer I decide to stick with replacing both pistons/rings. No add'l labor cost as it's already apart. My last sled went 8200 miles with original pistons and rings so hopefully this will run from 2500 (where it is now) to over 10K without having to come apart again.

We also have a 2000 600 with VES and at 5K miles it's coming due for a top end rebuild. All original and runs great but wondering if it might make sense to replace the valves at the same time......

 

[Pizza Man]

My 05 700 XCSP broke the right side valve at 2,500 miles.
Took it to the dealer and he had to replace the piston and valve.
I read some place that they are now making the valves out of a stronger material.
I sold my wifes sled and gave the Polaris to her. She only goes riding 1 or 2 times a year.
I then went and bought a new 08 Apex LTX.
Just put in gas and go.

 

[penaltyvectors]

My 800 switchback just broke a VES valve this last weekend up in Michigan. The clutch side VES valve broke below the stop and went right into the cylinder. I need to replace the cylinder, piston and the valve. If they are making them with a different material I think I'll just buy two of the valves and hopefully not have to worry about the other one breaking.

Dave

 

[flopnthenutz]

My 05 700 xcsp also broke a valve 3 weeks ago.
New pistons, rings, valves and replate 1 cylinder.
Sounds like a common polaris problem

 

[vx700xtc]

A two stroke with 2500 miles, its allready apart... you couldnt pay me to reuse the old piston.

 

[fredster]

On the 600's, the service manager told me the new valves are made out of stainless steel? I am picking the sled up next Saturday and ask them about this to verify -

 

[G]

On the 600's, the service manager told me the new valves are made out of stainless steel? I am picking the sled up next Saturday and ask them about this to verify -

Stainless steel valves hung together longer in the 800s - it makes sense that they would go to them for the 600 also.

 

[02edgehead]

as i posted in thread #12, the new valves ARE stainless. and as far as the comment made by vx700xtc, i hope im not alone in saying that 2500 miles on a 2 stroke is not piston replacing miles. i know several people with over 10000 miles on a 2 stroke and still have never touched the top end. if pistons look good with no damage why replace them?