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VES Valve Assembly

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60K views 38 replies 17 participants last post by  BC_Dan  
#1 ·
There have been a few guys asking about cleaning the VES valves on Polaris sleds. I looked in some of my pics and have these to share...

First off, there are two bolts holding the VES valve assembly to the cylinder. Remove those and remove the valve body. If you're careful, the gasket may stay intact. Have two gaskets on hand in case you're not lucky.

Here's what the valve will look like on your bench...



Remove the two remaining bolts. Inside will be the bellows and a spring. The spring side of the bellows should be clean, the underside will be coated with very dirty oil.



Remove the valve cap from the guillotine. I find wrapping the guillotine in a towel and putting it in a vise to hold it works well. That should leave you with all the parts disassembled.



Clean all the parts, replace old and worn bellows and springs



Assembly will be continued
 
#3 ·
Very nice post I'll have to inform my Dad about this.
 
#4 ·
VES Assembly

Insert the guillotine valve into the housing, and align the washer, bellows, and cap. Lightly coat the bellows with fresh oil Use blue loctite on the threads, and torque the bellows cap to about 6-8 ft. lbs. DO NOT OVERTORQUE.



Install the correct spring onto the bellows cap, install cover using two bolts. Use blue loctite, torque 4-6 ft. lbs.





These guillotines are the newer stainless steel parts, you can see the hollowed areas that help reduce the weight of the valve. If your valve has these intents, they are not aluminum.

Insert the valve back into the engine. The guillotine is eccentric, it will only go in one way. Do not force it! Using blue loctite, torque the longer VES housing bolts 9-12 ft.lbs.



A few more notes...

There are different ways to clean the guillotines. If you scrape the carbon off, be very careful not to scratch the guillotine. A green scotchbrite pad works well after removing the majority of carbon build-up. The steel valves are a lot more robust and do not damage as easily as the aluminum ones. Some guys have had success using oven cleaner to get rid of the carbon, I have not tried that, but it may prevent damage to aluminum guillotines.

If you do not need to replace bellows or springs, you can remove the bellows assembly and clean the guillotine without completely disassembly. The guillotines do not need to be spotless; removing the majority of the carbon and making sure they are smooth will ensure proper operation. I still like to disassemble mine to ensure there are no holes or damage to the bellows, and that the spring is intact.
 
#7 ·
No sealant is required. It was probably sticking because of cooked oil.

That motor had just had the cases machined, new crank with wide PTO bearing, new VES valves, bellows, and springs, new pistons (just because) and then it got kind of toasted in the fire. Sigh. I got 400 miles on it, though :) The engine made it into another sled and is still on the snow somewhere, too!
 
#11 ·
Hey Dan these are the exhaust valves right? I cleaned mine last year and I'm sure they are due. When I go to bolt the covers back on should I torque it to 9-12 ft pounds? I did not pay much attention to torque when I put them back on. I have that black sludge crap leaking out of the cover from where it should seal so will be picking up a couple gaskets as well. What ultimitley happens if you do not clean them?
 
#13 ·
Because a 2-stroke cylinder doesn't have a valve train, the intake and exhaust is done by ports in the cylinder. A manufacturer can design a port that is good at low RPM for good low end torque or good for high HP at the top end, but not both. The VES valves make the engine act like the cylinder is ported for low end torque but when the RPM gets high enough, the pressure coming to the bottom of the bellows pushes the VES guillotine valve out of the way so the cylinder can have the high speed performance too. Gunked up valves will rob you of top end and there will be a really big decrease in speed and HP above the point where the valves open (usually 6000-7000 RPM, depending on what spring you have in the bellows).

You want to keep the valves clean to ensure they will move as necessary to give you both low end torque and high end HP.

Like bigvander said, if you have oil coming out of the hole in the VES cap, the bellows has a hole. It's also a good idea to keep a couple of gaskets around, they're not expensive and don't take up much room in the tool box ;)
 
#16 ·
okay guys, one thing I'm confused on is whether or not there should be air coming out of the VES valve assemblies when the engine is idling...
I cleaned mine on my 700 and the bellows looked to be in good shape, I applied a little oil to seal them, but when the sled idles, I can feel "pops" of air coming from the hole in each plastic cover...i don't see any oil or smoke coming from them so I just assumed it's normal...I'll pull the covers off again when I get a chance and have another look at the bellows
 
#17 ·
Shouldn't be any combustion gas coming out of the VES assembly. The bellows should trap any gas/oil below the bellows. When you take the VES cap off, the top of the bellows should be clean, the bottom will be filled with black oil.

How are the springs? I'm wondering if the spring is shot and what you are feeling is the bellows moving up rapidly with no spring resistance, forcing a bit of air up as it comes. Just a thought and a SWAG ;)
 
#20 ·
Yea the old oil just rubbed off, I didn't use anything that would damage the bellows.
The sled has under 3000 miles; the springs felt like they had plenty of resistance when I had the VES assemblies apart, and the bellows looked to be in good shape.
I don't usually take the valves completely apart because I was told that the bellows nut breaks easily but I guess it would be okay.
For what it's worth, I might just replace the springs and bellows and see if it makes a difference.
 
#31 ·
i was wondering if the curved side on the guillotin should be on the top or be on the bottom because i didnt pay attention when taking out which way it was but the guillotine can go in either way could someone please help
They only go in one way. The guillotine is offcenter on the stem.
 
#26 ·
I was loaded up in a 27' enclosed trailer with 4 sleds full of fuel, for a ride the next day. I had a catalytic heater running in the trailer, which was parked in front of the house. The trailer was full of ice and snow and I wanted most of it gone so some people new to snowmobiling could use the sleds the next day on a group ride. I checked it on the hour for 3 hours, some time between hour 3 and 4, fumes from a gas can on the 04 800 escaped and ignited, burning up the 4 sleds and the trailer.

I was on vacation that day and "my" guys had to come help me put out the fire. I don't know which was worse ;)