Powervalve hitting piston

[summ8rmk]

Am i the only one that has this problem?
Second sled, same problem.

GS6

 

[armey37]

Wtf?? thats crazy. Are you power cable to spec length?

 

[summ8rmk]

The cable does not hold the valve in place, there is a tab on top of the valve that rests on the jug, preventing the valve from entering the cylinder.
Last sled made it 3,800+ miles, this sled has less than 1,500.

Here is the other piston. It has contact from both sides of the valve.

 

[F_ast]

Looks like cold seize. I bet if you pull the top end you have the same on the back side of the piston.

 

[scratley]

If the pv was hitting your piston you would have a nice shiny piston in many pieces. Laydown motors will have a few scratches on the exhaust side, just the nature of the beast. Getting a bid of blow by though. How many miles? might be time for a new topend..

 

[summ8rmk]

Its not a cold seize, its the exhaust valve.

GS6

 

[scratley]

Any damage to the rings? its hard to tell from the pics. But they do seem awful close. If it was touching it would catch a ring and boom.

 

[knifedge]

-Pull the power valve and see if there are wear marks on it,,,,if not then likely a cold seize

--Looks like there is material missing from the piston ring as well,,,

--Seems the power valve would make more contact on the piston though. if that what it was

 

[Cat800]

Its not a cold seize. Its the powervalve hitting the piston. I had the same issue

The stop tab on the powervalve hits the stop in the cylinder and will wear the cylinder. You could pull the powervalve and grind down the edges of the powervalve, but untill the cylinder is fixed it going to get worse. If you remove the powervalve from the cylinder, and look where the powervalve stop makes contact with the cylinder-you will see the issue.
Send the cylinders to Millennium Technologies and they will repair them/hone them. Then install new piston rings.

Do a search on this topic, there are a few older threads about it.

 

[Cat800]

If the pv was hitting your piston you would have a nice shiny piston in many pieces. Laydown motors will have a few scratches on the exhaust side, just the nature of the beast. Getting a bid of blow by though. How many miles? might be time for a new topend..

The two edges of the powervalve will make contact with the piston before the rest of the powervalve will.

 

[kiliki]

you can also get carbon build up on the valve and it will leave marks on the piston too but not damage the rings.
as said above pull the valve and look at the seat/stop point on the jug for and indent from the valve stop.

 

[summ8rmk]

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[summ8rmk]

I know what is happening, my question is y?
This is the bullet proof cat 800.
Why are my cat 800s having the same problem. Oil related?
I have ran the same oil in all my sleds.

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[kiliki]

put the grinder to the valve edges, will not affect it a bit.

 

[summ8rmk]

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[Cat800]

Has nothing to do with what oil you use.

The aluminum cylinder seat is being deformed by the powervalve stop. Your pic shows the problem.

Its not just you 800's having this issue

 

[summ8rmk]

I figured my 09 was worn from 4,000 miles, my 14 has less than 1,500.

GS6

 

[Cat800]

Mine had less than 1500 miles on it to. I ground down the edges of the powervalve and ran it 200 more miles and pulled the pipe to inspect the pistons and it was worse. It seems once that aluminum starts to deform it will continue to progress. Thats when I sent the cylinders in and put a new top end in it. Ran if for a season and rechecked it, and it looks like brand new.

 

[JasonAK]

I have seen this happen to at least a dozen Cat 800's. The power valve stop gets deformed/smashed down on the cylinder. It happen to two of my own sleds. I purchased new jugs to solve the problem.

 

[sno*jet]

are you on and off the throttle a lot? trying to picture what breaks down the seat inside the jug...