Dear Ralph: While prepping my sled for summer storage this past spring, I found that my ’04 Polaris 800 XC SP (with the stainless...

Dear Ralph:
While prepping my sled for summer storage this past spring, I found that my ’04 Polaris 800 XC SP (with the stainless steel power valve mod, both cylinders) had stripped all the treads from the top hat nut that attaches the power valve to the bellows. The valves still moved freely within the cylinders and its threads were like brand new. This happened to both cylinders. Luckily all the metal shavings were contained within the valve body and bellows. As I recall during the winter, I had just put 400 or 500 miles on the machine when I couldn’t get it to go over 7200 RPM. Since I was on a long trip (another 400 miles to ride) I couldn’t trouble shoot it until I got home. My questions are: Is there a different, stronger nut for the Stainless Steel valves? Something made out of Stainless Steel? Does the extra weight of the valve require different bellows, springs? Anybody else having this problem?
Ray Fitzsimons
West Bloomfield, MI

Over the years as the engine performance and calibration of the Liberty 800 big block changed, the amount of heat the valves were exposed to also increased. This is more of an issue on the 800s than the smaller engines (like the 700) due to the larger bore of the 800, resulting in less room for coolant flow around the valve area on the 800.

In 2003, Polaris was using aluminum valves. In 2004, they upgraded to “hard coat anodized” valves, followed by stainless steel valves in 2005. All of these valves now supersede to the “Stainless Steel Valve Kit” (Polaris part #2202838). This kit contains the #5134492 stainless steel exhaust valves and valve springs (kit instructions provide information on what springs to use for what elevation).

Titanium valves were released as an accessory for MY05 for the 800, but with the success of the stainless steel valves the titanium accessories have since been dropped from the line.

Polaris went to the Stainless Steel valves in MY05 on the 800 using the aluminum cap nut, with Loctite 242 applied to the cap nut. When properly cleaned, Loctite applied and torque to 16 ft./lbs., the valves are secure. If they were contaminated with any oily substance, the locking agent would not bond (this applies to any fastener when using any Loctite bonding agent). The threads of valve and cap should be cleaned with a Loctite primer “N” and then have Loctite applied.

The cap nuts have transitioned from aluminum to anodized aluminum (Polaris part #5631687). In MY06 all valves were installed with the anodized cap nut and Loctite 242.

For the absolute best retention of the cap nut when using stainless or titanium valves, you could use Loctite 2760 (Polaris Part #8560107). The torque specification for both stainless steel and titanium is 16 ft./lbs. (+/- 2). When this Loctite 2760 is applied, a heat gun will have to be used to remove the cap nut. The use of 2760 Loctite on aluminum valves with aluminum cap nuts is acceptable. However, the nut will have to be heated to 350 degrees prior to attempting to remove it from the valve stem. The torque specification for aluminum valves with the old aluminum cap nuts is 12 ft./lbs. (+/- 2)

Polaris also wanted us to remind customers that they should always use high quality 2- stroke oils designed for variable exhaust valve engines. In the Polaris Service manual it is recommended to clean the valves every 1000 and 2000 miles, as well as preseason. Appropriately servicing a heavily carboned valve will minimize the chances for valve damage.

Also, the vehicle Owners Manual for 2003, page 125, states the customer should take it to his dealer for cleaning and servicing, as well as mentioning the use of proper oils.

  • David

    December 25, 2006 #1 Author

    I have a problem with my ves valves and I have been changing valves and wasting money and I have no idea how to avoid braking valves and so far the valves that brake off have damaged my pistons and two cyliders which is a problem for me cause I dont have the money or the time to keep fixing so if you could help me find a way to fix it e-mail me. Tried stainless steal but the cap nut would strip!

  • Ryan

    February 18, 2007 #2 Author

    I have a pro x 2 800, and I keep having ves valve problems similar to many others. I hvae had the threads pull offf the valve, one brake the rod, and one bend the end at the cylinder. I have replaced cylinders and pistons due to this and I’m getting tired of replacing parts when I can not find a reason to cause the to bend or brake.

  • pj

    February 8, 2009 #3 Author

    I have a 05 xc sp 800 with about 4000 mi the valves have broken just about every season my recamended soultion is dont buy another polaris

  • polaris800

    March 12, 2013 #4 Author

    there is a simple fix for your problem, either you are buying cheap parts that are not rated for the stress that they have to take or you are putting the wrong valves. i have had several polaris 700 and 800 sleds in the past 10 years, they have all had power valves and i have never had a problem with them or have heard of someone breaking them. if you get the right part and dont get the cheap one you will never have a problem and will beat any other piece of crap sled out there.

  • jimmy

    March 12, 2013 #5 Author

    I agree with polaris800. polaris is the best sled out there. i also have never had a problem with them. i always thke the vlaves out every year and clean them. i have a 2003 polaris 800 rmk with over 9000 miles on it. i had to replace the pistons and cylinders onece because of a oiler problem but i am useing the original valves. proper care of them and they will last a long time

  • John

    October 30, 2013 #7 Author

    I just bought a 2002 edge xcsp 800 and are reading all these horror stories on these power valves.. Now I’m looking to change mine on the sled I pulled them out and they are all gunked up what do I do? What valves do I put in? And where can I purchase them thanks!

  • mike

    March 21, 2014 #9 Author

    where to start. ok , so i have had one 04 700 rmk break the ves , i kept driving and now have a bent rod , chipped cylinder , and only pieces of a piston. i found out it has the cast ves and because of wear , it hooked the piston and broke. so anyway , i needed a sled quick and bought a 03 rmk 800 , towards the end of the first season i noticed what sounded like a flooding problem at higher rpm , replaced the bellow and sounded good again. then after a 100 miles same thing at the recommended cap torque , however , this time the cap came loose, put on a new cap at 20 torque and no more problems. then the beginning of this year 2014 the motor was running lean, found out it had a crank seal leak , pulled the motor and found that the stainless steel ves corners were touching the piston and as a result the rings were somewhat stuck , done a quick patch up job , cleaned the ring grooves , ground the ves corners to the recommended clearance to pass the piston ” this is from wear and the ves drops a bit closer to the piston and will move from side to side and thus the corners will touch ” put in two new crank seals and the motor is running strong , sounding great. i have also heard that a easy way to identify the diff between cast and stainless ves is that the stainless have two square like indentations and the cast are one solid piece of pig iron that will eventually fall into the piston and make a down the line owner loose his hair from stress. just joking about the loss of hair. i hope this helps someone to prevent a high cost repair.

  • mike

    March 21, 2014 #10 Author

    oh and , it was a clutch side seal , the recoil side will usually make the motor bog as this is the side that usually has the vac hose for the fuel pump. oh and when i said about the ves clearance to pass the piston , i ment to say the ves clearance for the piston to pass the ves

  • mike

    April 4, 2014 #11 Author

    one thing on the stainless ves , i mentioned that i put the cap torque to 20 foot pounds , do this at your own risk as the max recommended torque is 16 foot pounds , so it be best to clean the threads properly and use red threadlocker , and remember that when it comes time to change the bellow , you will need to heat the cap to remove.

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