RMK EVO upgrade kit

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
After a couple of rides on the new EVO I need to upgrade it for my grandson. I already have all the Pro shocks, new longer limiter strap, Pro running board takeoffs and possibly the throttle (gotta look). The upgrade kit includes a clutch spring and weights but they are for 0 - 4,000' so they don't do me any good - we're at 8,000' and above so we'll clutch it after the upgrades. We may or may not change the gearing. I will drop the skid to the lower holes in front and drill a new hole 1" lower and 1/4" back in the rear bracket. From other posts and sources that appears to be the right spot. I might chop the tunnel a bit. Since there are no coolers to worry about it's pretty simple and right now the tunnel looks extra long.

Does anyone know why Polaris includes a new CDI box in their kit? It's the exact same part number as the original.

Anything else I am missing?
 

beans

Well-known member
Nov 27, 2007
285
63
28
Preston, WA
I am considering purchasing an RMK EVO for my daughter. In stock form what makes the sled a poor performer? Is the low height pretty limiting off trail?

I am already adding up the cost to mod the sled. Are Axys and Pro shocks the same lengths?

Please document your mods! I am excited to hear how it goes.
 

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
In stock form it's pretty low to the ground and the drag factor is what gets it when it's off trail but being that low to the ground makes it nice and stable going down the trail. My grandson is much more confident and rides faster down the trail on it than he did his old Indy Lite 340. ( which makes it a more pleasant ride for all of us because trail time is wasted time! ;) ) Also the throttle flipper is designed to only open the carbs part way which works well on the trail but off trail can be pretty limiting when you need power. I think it would be perfect for a younger child than mine - he's just too big for it already. With the stock setup it's runs 48 mph down the trail with me on it so it's not a slob power wise as it is but it could be much better with access to all the power the motor can make.

If I still had little kids ( 5 to 9 years or so) it would be perfect just the way it sits. As it is we are past that stage and need to change the setup. Since it is a Pro chassis a full set of shocks off of a Pro will fit. The Axys chassis is different so I don't know what will fit or not. I am actually doing the shock swap tonight so I will take measurements and pictures as I go. Interestingly my grandson can already get it up on one ski so I expect he is going to be shocked the next time he rides it! I'm sure he'll tip it over sometime in the first five minutes!

The ergos are great by the way - he's not a big boy and the sled fits him. That's why I'm willing to spend a bit to mod it.
 

powdrdaz

Active member
Lifetime Membership
Jan 15, 2012
136
29
28
Hi Catey5312. did you find anything about the cdi box? I looked it up and the part numbers are the same. sorry just reread your first post
For beans the new snowest has a good article on Chris Burant's build on the Evo
 

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
I did not find out anything about the CDI box. My dealer did a Chris Burandt install and they didn't change the CDI box either. I looked at that sled - it came out pretty cool although they didn't chop the tunnel. That's kind of a Burandt thing. I'm not going to the expense or trouble to change to the React front end though, I'm sticking with the Pro. I don't have ten sets of takeoffs laying around like some folks might (Burandt). (Wish I did - I'd slap one on my 2017! Love that new front end )

I have an Indy 550 throttle from a 2014 - different part number than the 2020 - wondering if I can use the 2014 on it? The Poo upgrade kit uses an Indy 550 throttle with the 2020 part number. The Evo throttle is physically flatter so the distance that it can pull the throttle cable is about half of a regular throttle.
 

powdrdaz

Active member
Lifetime Membership
Jan 15, 2012
136
29
28
I was thinking about cutting my tunnel so my cover will fit. I'm also going to stay with the pro front.
Would like to change the running boards but I'm afraid her foot could fall through the openings.
 

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
The running boards are a definite issue. After a couple of hours in the powder both of them had 4 to 5 inches of icy snow built up on them. RSI used to make what they called 'dumpers', you rivet them to the running boards and cut out the openings. The openings are smaller than a Pro running board. That might work for you. There's still alot of them for sale on ebay - just gotta be careful - I ordered a set for a 550 Voyager (same running board as the EVO) and even though the ad said it fit Polaris they sent me Ski Doo which were 3/4" too wide. I cut them down but lost 6" in the process.
 

Reeb

Modding mini's
Lifetime Membership
Jul 6, 2001
2,848
992
113
35
Twin Rivers
www.robinsms.com
We just did the upgrade to a friends EVO for his grandson. a Pro or Axys throttle block and flipper works perfect. The Axys one is cheap too since its plastic. We were going to throw a 144 under the sled but found a nice 136x2 and we used instead. Makes a world of difference going to a better track. The clutching they give you is dismal at any rate. We were at 3500ft and it wouldn't pull 6200rpm up a small slope. A few changes back at the shop and we had it running right on the money. We didn't swap a ECU as my dealer said it was not needed. I don't see a gain by going that route now that this thing can hang with the older 550's across a lake and in the snow now. No loss in performance has been seen by keeping the stock ECU.
 

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
The only challenge with the flipper is making sure you get the right length of pull. I used a 2014 550 Indy flipper - the length of pull appears to be about 1/16th of an inch greater than the flipper part number Polaris specifies. I can't feel the carbs bottoming out so I think it's ok.
 
Mar 13, 2019
109
80
28
On a sled this size, what are your thoughts of the 136" vs the 144" offered on the RMK model?

A nieghbor has the indy version and it sits SO low in the front end. I would bet it's not much higher then the kids Indy 120?? Are the Pro shocks lifting the front of the sled as well or does that require a spindle change.
 

powdrdaz

Active member
Lifetime Membership
Jan 15, 2012
136
29
28
I don't know about the 136" but for the RMK new shocks and a limiter strap will get them up off the ground
Cateye5312 when you did the shocks did you install the torsion bar ?
 

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
I don't know about the 136" but for the RMK new shocks and a limiter strap will get them up off the ground
Cateye5312 when you did the shocks did you install the torsion bar ?
I did not.

The EVO 121 has the same front end as the RMK EVO - same part numbers for shocks, A arms, spindles. On my RMK EVO switching to the Pro shocks lifted the nose 2 1/2". Dropping to the lower holes in the front tunnel bracket, drilling a new hole 1" lower in the rear bracket and adding the Pro track shocks raised the rear of the sled 3" - and that measurement is at the rear bracket not at the bumper. If I owned a 121, I wouldn't hesitate to put a 136" under it and switch to the Pro shocks. As a matter of fact I'm thinking about buying a 121 and putting a 144 under it (because I own a 144 track and suspension off an Indy LXT ) Talk about a shorty tunnel!
 
Mar 13, 2019
109
80
28
Ok THANKs for the info. I've got the kids on the 120s right now (one of them is long tracked) and I am hoping to find someone that wants to upgrade to the Evo RMK over their Evo 121. I have a 136 track sitting on the floor that could work. I would still like to lighten the Evo up a whole bunch. That's the only thing that intrigues about the Blast 400. That engine could be REALLY sweet if they get the sled down to sub 375 lbs.

I really like the possibilities with the Evo too, I just wish it was lighter for that 120lbs rider
 

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
The RMK EVO has a claimed dry weight of 420 lbs (which is 55 lbs lighter than the 2008 340 that my kids were riding FYI). I wish I had taken the time to weigh things as I was switching. Each Walker Evans shock that I put on felt like it weighed 2 plus pounds less than the ones I took off plus I dropped a couple of the bogie wheels. I'm thinking I lost ten plus pounds - next is to cut the tunnel and swap the boards out which should reduce it some more. And with a smaller gas tank there's 16 or so pounds we're not carrying around. What is the dry weight of the Blast?
 
Mar 13, 2019
109
80
28
I think the blast will be in that 425lbs mark as well. They claim the engine is only 55lbs. Lots of options.

I'll have to weigh the 120 now that it has a 208cc and the long track (and electric start with battery) I can still lift into the truck myself so I am guessing sub 200lbs. For myself (and our kids) that smaller chassis long tracked (121" would be fine) with a 300cc 2stroke, chain case and proper clutch would be the ticket at sub 300lbs.
 

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
Here are the before and after shots of the height difference from switching to a set of Pro shocks and dropping the skid to the lower hole upfront and down 1" in the back.
 

cateye5312

Well-known member
Premium Member
Mar 28, 2009
800
444
63
Grand Junction CO
Here's a shot of one running board installed - took two hours to get to that point. In order to attach the axys running board to the EVO up front, we took the front attachment off the axys running board by heating it, drilling the rivets out and tapping it out of the board, took the old outer edge off the EVO's boards, split the tubing that held the EVO's old outer edge on, slid the Axys board on over that, clamped everything down, marked all the openings, took it all back apart and cut out all the unnecessary aluminum. Then we re-mounted everything and riveted it all back together. It came out looking pretty nice. ps - I had to split the tubing because there is a vertical web inside the Axys tubing and I didn't want to cut it out for structural reasons. 5931.jpeg
 

FlynHigh

Member
Premium Member
Jan 3, 2008
50
11
8
CatEye That is sweet!!!! Any chance you have more pictures showing how you did it?? Also do you know what they eye to eye measurements of all the shocks are that you used? I have set of front Fox shocks that are 17.5" from center to center of the eye. Wondering if these shocks would work. Did you change the A-Arms to ones you took off a Pro or just stick with the EVO A- Arms? Did you change spindles? Is the caster or camber affected by these longer shocks?
 
Premium Features