Valve check?

[Allan]

I would be surprised if it was warranty. Hopefully it is. Shim under bucket valve adjustments area a pain.

Why would it not be? My machine in under warranty , I followed the maintenance schedule and under the km for valve inspection and the km of the warranty. I had 3 years warranty , 8 month left and up to 20,000 km. Machine is now having trouble, they have to fix it if it weather it the valves or something else. Seen in other post where one person has the head replace when having this problem.

 

[DVW]

Why would it not be? My machine in under warranty... Seen in other post where one person has the head replace when having this problem.

The first time my valves tightened up at 15,000 miles my cost to replace the the cylinder head was shared with Arctic Cat. Is was decided to replace the whole cylinder head because the root cause had not been found but it was assumed to be a defective part. The second time at 24,000 miles I paid the bill for valve adjustment and inspection.

 

[Allan]

The first time my valves tightened up at 15,000 miles my cost to replace the the cylinder head was shared with Arctic Cat. Is was decided to replace the whole cylinder head because the root cause had not been found but it was assumed to be a defective part. The second time at 24,000 miles I paid the bill for valve adjustment and inspection.

was your machine under warranty at 15000 miles? If not I would think shared cost was good.

 

[Allan]

Did the Nytro have this problem? I would think there must be some high millage Nytro's out there.

 

[DVW]

was your machine under warranty at 15000 miles? If not I would think shared cost was good.

My machine was not under warranty. The problem was difficult to troubleshoot and my dealer (Lighthouse Motor Sports) and Arctic Cat spent a lot of time to determine that a warmup issue was tied to tight valves. I was very happy with the support I got.

 

[DVW]

To the best my knowledge the root cause of my valve tightening problem has not been found. It is possible that the problem can be uncovered on this forum. The root cause is either manufacturing, design or application.

The fact that my valves got tight after complete replacement of parts does not rule out manufacturing because the Arctic Cat service parts where probably made early on when my 2014 machine was built. Input for this group would be helpful here with regard to what year machines are having problems.

If it is a design problem with the Nytro engine than why did this not well up years ago. Maybe a application problem with the Nytro engine in the Viper/7000. If so why didn’t others have this problem when I did two years ago?

Maybe it’s the way its driven. Maybe I drive too slow and the Nytro motor with performance camshaft does not like to be driven slow. Some people say they average 60 to 70 mph and I only average 32 mph based on numbers from my speedometer. Am I the only one that averages 32 mph?

A pattern might emerge if the people who have this problem compare notes.

 

[DVW]

...The big question is if out of spec and adjusted will they go out again?

I agree that is the big question. If this turns into a pattern (it might not) than it takes some of the justification out of selecting a 4-stroke. This could be a big deal, or maybe not we will see.

 

[Allan]

I agree that is the big question. If this turns into a pattern (it might not) than it takes some of the justification out of selecting a 4-stroke. This could be a big deal, or maybe not we will see.

I would agree with this.

My sled is a 2016 and they made several changes in 2016. , in 16.5 motor they changed the camshaft, New cylinder head design, and valve stem oil seal, valve spring seat.

 

[cobrajet ltx dx]

I’m wondering if the exhaust valves that are used are sodium filled?
If so that could be why the clearance is getting tight. Running 5-9 thousand rpm most of the time could deteriorate them faster causing the valve face to be sucked into the head seat causing tight tolerances. The reason why manufacturers use this style valve is for cooler temperatures.
My theory is totally on my Subaru sti experience which I’ve seen countless times over the years.

 

[DVW]

I would agree with this.

My sled is a 2016 and they made several changes in 2016. , in 16.5 motor they changed the camshaft, New cylinder head design, and valve stem oil seal, valve spring seat.

Thank you for identifying the changes in 2016. Looking at the service parts lists I can see the following. The two different cams used on the Viper/Nytro and the Vector both changed in 2016. The cylinder head used on both the Viper/Nytro and Vector also changed in 2016. Maybe the change to these 2016 models was in response to tight valves. I will say that in early 2016 Arctic Cat factory service worked hard on my warmup issue and tight valves was not on their radar. When do you think the changes where made? Does anyone have a 2016 or newer machine showing symptoms?

 

[Allan]

Mine is a 2016 with the changes listed above. we call them 16.5 as in 2016 the early build never had the updated changes

 

[DVW]

Mine is a 2016 with the changes listed above. we call them 16.5 as in 2016 the early build never had the updated changes

Allan
So your machine has the symptoms and the updated head and cam. If your machine with the newer head and cam ends up having tight valves than the changes might not be a response to tight valves. What do you think?

 

[Allan]

Allan
So your machine has the symptoms and the updated head and cam. If your machine with the newer head and cam ends up having tight valves than the changes might not be a response to tight valves. What do you think?

My Machine has all the symptoms that was listed for tight valves. Going to take it to dealer in about a week. If mine do have tight valves this means motors with the changes and before that changes had tight valves.
I don't think there are many 2016.5 out there with 11500 miles like mine so hard to tell if the head and cam changes helped of hurt.

 

[DVW]

My Machine has all the symptoms that was listed for tight valves. Going to take it to dealer in about a week. If mine do have tight valves this means motors with the changes and before that changes had tight valves.
I don't think there are many 2016.5 out there with 11500 miles like mine so hard to tell if the head and cam changes helped of hurt.

If your machine has tight valves than I think the changes had nothing to do with tight valves - my opinion.

 

[cannondale27]

I agree. And till we all confirm whether we in fact have tight valves not much can be assumed. I believe they varied right from factory or shortly after. Probably will never prove that but it sure makes sense to me. Now if that's not the case it's really a issue because then it's either a defect or dirt causing it. Both will not be cured by just a adjustment. They will go tight again. I plan to take the dive in this weekend if I can stay away from all the snow coming in next few days!