Ever see a Power Valve make contact with a piston?...I have :(

M.M. 700 · Feb 23, 2010

On my 2009 M8 with 420 miles I noticed after riding for 2 days the coolant level was down to the bottom of the coolant bottle.

So tonight I did a PSI test on the coolant system. And found coolant seeping out where the head meets the cyclinder. So while pulling the head bolts I noticed where it was leaking the head bolts were just more than finger tight (Thanks Cat). But I decided to pull the head instead of just tighting the head bolts, and order new O-Rings. And to make sure the coolant didn't make it into the cyclinder...which it didn't.

While I had the head off, I was looking at the piston. And on the exhaust side cyclinder (were the head bolts were loose and leaking coolant) looks like cornor of one side of the the power valve made contact with the piston. It doesn't look like it harmed the rings, but the piston has some marks on it.
Now I am wondering why the power valve made contact with the piston??? And If I am needing a new piston and rings?

I have pics but do not know how to post them. If somebody would, PM me there E-Mail and I can send the pics for them to post.

M.M. 700 · Feb 23, 2010

Also is there a trick to getting the coolant hose off and on the back of the head? I have the head unbolted, but it looks like the rear coolant hose is a PITA to get off and an ever bigger PITA to get back on again

KSH · Feb 23, 2010

M.M. 700 · Feb 23, 2010

In the second pic where the screwdriver is. The edge of the piston is not a smooth radius, it is sharp edge and pushed inward slightly. But didn;t turn out in the pic

Thanks for posting the pic KSH!!

WyoBoy1000 · Feb 23, 2010

is it under warranty

JasonAK · Feb 23, 2010

I had the same thing happen to my M8. If it is under warrenty make them fix it.

I thought I was the only one, only happened on one jug the PTO side. I had to grind down the power valve to clear piston.

Jason

bgreen776 · Feb 23, 2010

how could the valve hit the piston and not the rings?

M.M. 700 · Feb 24, 2010

No warrenty

Is there anyway the power valve is out of adjustment, and that is what caused this? I wouldn't think that it should be able to ever make contact, weather the adjustment is out or not.

So I need to grind the power valve? Think I need to replace the piston/rings? I think am going to try to get one more trip out of it. Then I will be done sledding for the year, and I can put a new top end on it this summer.

M.M. 700 · Feb 24, 2010

bgreen776 said:
how could the valve hit the piston and not the rings?

It hit the rings, but did not damage the ring. Just scuffed the piston

Sunridge Sledhead · Feb 24, 2010

I had that happen to my 1M. I rode it without any problems, or noticeable performance issues. I ground the power valves down a bit and never had a problem.

Arctic Thunder · Feb 24, 2010

M.M. 700 said:
No warrenty

I think am going to try to get one more trip out of it.

I would just touch the tips of the PV with a grinder before the next ride. If it catchs the ring you will be done and have a lot more problems to fix over the summer.

Thunder

M.M. 700 · Feb 24, 2010

Yep, going to grind the tips of the PV.

AaronBND · Feb 24, 2010

M.M. 700 said:
No warrenty

Is there anyway the power valve is out of adjustment, and that is what caused this?

The adjustment is only for them opening, not sitting where they are suppose to in the cylinder. Sorry, but that's fu*ked up on a new sled! I can see it on a bored jug where a guy forgot to grind them shorter, but on a brand new sled from the factory?

Aaron

gopher-it! · Feb 24, 2010

nick

M.M. 700 said:
No warrenty

Is there anyway the power valve is out of adjustment, and that is what caused this? I wouldn't think that it should be able to ever make contact, weather the adjustment is out or not.

So I need to grind the power valve? Think I need to replace the piston/rings? I think am going to try to get one more trip out of it. Then I will be done sledding for the year, and I can put a new top end on it this summer.

this has happened twice to kids m8, warranty both times, it is were the power valve sits in the cyinder, new cylinder last time.09 m8.

skibreeze · Feb 24, 2010

I had the same thing happen to my D8. Looking at my pv's, you could see that they actually curled inward at the tip. I'm guessing that it was from the extreme heat softening the tips. I also just ground them down to clear the piston.

JasonAK · Feb 24, 2010

I had to replace the piston and rings.

I just hit the tips with a hand file.

Jason

907KB · Feb 24, 2010

.
Yours doesnt look like it was hitting as bad as JasonAK's. Looks to me like it was just enough to push the rings in and mark the pistion. probably just a couple of thousandths.
If it comps out the same on each side and the rings have no visable damage. I would'nt mess tearing it down. Just file the tips of the valve back to business..
On JasonAK's sled there was a good amount of ring damage.

M.M. 700 · Feb 24, 2010

So This is a design flaw caused by the difference in tolerances in the cylinders?

Destroyer · Feb 24, 2010

Our dealer has seen some issues with 09 800's.

Ever see a Power Valve make contact with a piston?...I have :(

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