RMK Evo clutching, jetting, etc.

[law.74]

Last season our RMK Evo did not perform as well as we would have liked. This is partly by design when polaris decided to make the thing a dog so you'd pay $1500 plus installation for an "upgrade kit". Also my fault for not setting the sled up for our elevation and expectations. Looking to remedy this now...
I have purchased a new spring for the primary clutch, new gears for the chain case as well as other suspension and running board mods in the works. What I am yet to address is carburetor jetting. According to the manual I need to downsize the main jet and adjust the clip position.

I'm looking for advice and experience with this process. All of my other toys are EFI so I lack experience in this arena. Any do's and don'ts when tearing into the carbs? Obviously this is not something I'm going to do often to account for ambient air temperature. Any advice on picking the sweet spot temperature wise? Polaris chose -15 to +5 F (-26 to -15 C). This is an obviously ever changing variable.

Anyone know where to find a service manual for this sled (or carb)? The owners manual conveniently leaves out how to adjust the carbs.

Regarding clutching and jetting for elevation... we tend to ride 7-9k feet. The manual offers settings for 6-8k and 8-10k. Which should I gravitate toward? Clutching is easy to adjust later. Jetting, not so much...

Any other reasonable performance suggestions would be greatly appreciated. Hopefully the kid outgrows the sled this season and we will move on to 600+ axys, but for now we need to make the most of this sled.

Thanks in advance,
Law

 

[Bushwacker1]

To keep your carbs in tune for temp changes automatically with out changing jets I would recommend installing a Holtzman tempa flow device. This device has you install -20 jetting in your carbs for the elevation you ride at, it taps some engine vacuum and varies the float bowl pressure to lean it out at temps higher than your starting point jetting of -20. Your sled will always be good for temps down to the -20 jetting you start with. I installed these on at least 10 carbed sleds between my own and friends sleds over the years and can say this is truly one aftermarket product that works as advertised. Very little to no fine tuning of air screw/ fuel screw/ needle position is required. Any fine tuning that I experienced was to the low speed off throttle circuits, but most installs required no adjustments. These clean up the rich jetting that carbs normally have in them that is safe on the coldest riding days but much too rich on 98% of the days you are out ridding. There is also a manual adjustment that can lean or richen your initial setting slightly by unplugging a hose and turning a screw. This can be used to fine tune or adjust for some elevation changes if you ride out of more than one elevation within a few thousand feet of each other. Install require some skill to drill and install the vacuum port into one carb, with the flat style rack carbs being the easiest and the kiehen carbs being the hardest. You also have to drill a few holes into the air box to install the device inside, the rest is just routing tubing to the device and to the carb bowl vents. Holtzman still has a site that I think you can order from. SLP sold them also but I am not sure if they still do. This device accurately leans the fuel delivery according to the temp it sees inside your air box. The only precaution to using this is that when you stop ridding for a few min (lunch or other break) your air box temp will raise, so when restarting they recommend a non full throttle drive away to allow the air box temps to normalize. There may be old posts with more info on snow west on these if you do an advanced search.

 

[Bushwacker1]

Your clutching may also require removing weight pucks inside your drive clutch if it was initially set up for a lower elevation than you ride in. Polaris sells a repair manual that has clutching and jetting specs for elevation as well as direction on how to perform these tasks. They are kind of pricy but this puts all the correct info at your fingertips when it is needed. I have two 2019 indy evo trail sleds and there is a wire that can be disconnected to eliminate the speed limiter without having to purchase the upgrade kit with the new CDI. There were posts about that process here on Snow west also. The one I long tracked to 141 could muster 70 MPH across a lake back here in the flat lands of upper Michigan.

 

[law.74]

Thanks for the response and suggestions. I definitely need to learn more about the tempa flow device. Sounds interesting.

I definitely need to pull some weight from the primary clutch. Fortunately the upgrade kit instructions walks through that process. I now remember reading about that wire early on. I wasn't too concerned about top speed at first but I definitely need to find it for this season.

 

[law.74]

Too chicken to drill / modify the carburetors. I adjusted the needle clips and installed a main jet for my elevation. Praying for snow to test it out...

Clutching still needs to be adjusted pending purchase of the right springs and a 1 7/16 socket. 36mm is too small.
I read I can work on the primary on the sled without pulling it. Any comments to that effect?
I don't own the puller for this sled...

 

[gmacp]

Your clutching may also require removing weight pucks inside your drive clutch if it was initially set up for a lower elevation than you ride in. Polaris sells a repair manual that has clutching and jetting specs for elevation as well as direction on how to perform these tasks. They are kind of pricy but this puts all the correct info at your fingertips when it is needed. I have two 2019 indy evo trail sleds and there is a wire that can be disconnected to eliminate the speed limiter without having to purchase the upgrade kit with the new CDI. There were posts about that process here on Snow west also. The one I long tracked to 141 could muster 70 MPH across a lake back here in the flat lands of upper Michigan.

Hey Bushwacker1, I need the manual that you mention here, I have the owner's manual, and I bought another one needing more info, and they both are USELESS. Where might I find the manual you speak of. A link would be awesome. Thanks

 

[Bushwacker1]

Your local polaris dealer can order you a repair manual.