Polaris RMK 800 snowbike

[Hawkster]

The tracks already rub a little bit above , usually on the rear drop brackets , some models worse than others . So you may want to take that into consideration into the build . The track floats from side to side on the hyfax and the manufactures have narrowed the tunnels as much as they can , if it wasn't for the quality of track manufactures the tunnels of today would shred the old school tracks . No big deal with machines that have the power and at one time those drop brackets where designed not to hinder the width of the tunnel , funny how mistakes keep coming back .
A little trivia

 

[Brett Kobernik]

One of the things to consider is that Arctic Cat had a special track designed to go with the monorail. It has way stiffer support rods running thru it to help control how much the track flexes. If you use a regular track you may find that it will washout to easily on steep sidehills.

they make that track in various sizes from a 146x2.0 up to a 165x3 so I guess if you like the concept, you could buy one to go with your design.

I was wondering about this. I guess I’ll find out how a regular track works. Thanks for the thoughts.

 

[Brett Kobernik]

I haven’t made much progress with much fine tuning but I’ve been riding the thing a lot. I’m just so tickled!!

 

[Hawkster]

Nice , try stiffening your ski pivot up so it doesn't flex as much . You want the ski to help float but you don't want the ski to walk the terrain so easily .The aftermarket guys have figured this out , I accidentally did it since I make my own ski dampener , the factory ones tore all the time , who knew I was doing something people charge big bucks for

DuraPro Ski Dampener - Polaris RMK (Set of 2)

Replaces Polaris # 5415230, 5412794 and many others. The patented DuraPro ski dampener rubber offers many unique advantages including ...

www.duraprousa.com

Munster Ski Bushing Stiffener - Peakboys

Similar to the Ski Bushing Savers, the Ski Bushing Stiffeners stiffen ski articulation for better ski performance. Acting as a spacer underneath the ski rubber, they remove any extra play and applies more pressure against the spindle to stabilize the ski. Compatibility Installation Instructions...

peakboys.ca

Rigid

 

[Brett Kobernik]

Thanks for the suggestion @Hawkster. I'm interested about how you make your own.

 

[CATSLEDMAN1]

a must do on most all sno bikes, for sure MTHorse. Shims or/and DuroPro rubber. After a year I had to still shim my DuroPro.

 

[Brett Kobernik]

OK, I'm very intrigued. I haven't considered this before. You guys rock, thanks so much for the suggestions.

 

[J&L Snowhawk]

 

[Hawkster]

Very nice J&L , good for you , looks like a rush .
Brett , here is a version I use on the T/S and Yeti ski , the stiffer the better SPI makes them , supposable discontinued for some reason , like 10.00 bucks . You want that ski to really resist rocking . Rigid to the point that the heel of the ski holds the ski fairly straight .
Check on Kimpex also , lots of different versions .
Just get creative and secure the center hole to keep the rubber from moving .

 

[Brett Kobernik]

Yep, nice @J&L Snowhawk you got a build thread or more photos somewhere? You've seen the light obviously. I'd like to try a bike with the mid engine mounting position some time.

Thanks again @Hawkster I'll look for some of that stuff. I like the idea of just shimming my current bushings with some wedges under them. What do you guys think of that? Are these Timbersled bushings too soft?

To be honest, the bike felt great through the whoops even thought you can clearly see the ski flopping in the video. I mean, I can hit them about as fast as I can go. I'm excited to try with stiffer bushings.

 

[Hawkster]

It'll feel even better with a more rigid ski , think of it this way .
Right now it's like driving a bike with loose spokes , feels like a flat tire . It wonders and your constantly compensating , you just don't know it in this circumstance

It's actually really strange for a hard core sledder that rides any motorized bike and than climb on a one ski and ride it like a bike , they have a mind set to ride it like a sled and the only thing I can figure out is that it's the snow instead of dirt or pavement , I know sounds weird .

Also not making it sound like I'm taking sides it's just a comparison I'm trying to put in words .

 

[CATSLEDMAN1]

The loose ski bushing really goes bad when you turn in powder, the tip comes up you are trying to push the whole ski through the snow, take the bushing out and that maneuver will result in instant stall/fall. When we were building our own skis for the bikes way back, we over looked this minor detail bushing, wow oh wow, down the trail no big deal, out into the powder gliding under power, try and turn and you went down so quick it took us a morning to really figure out what was going wrong. The heavier the snow the worse it is. We put a cable from back of ski to spindle so ski tip could not rise above level, magic. So on the TS setup, when I bought my riot I didn't even ride it before I shimmed the back of the rubber. NOw have stiffer aftermarket rubber with shims.

 

[Brett Kobernik]

The loose ski bushing really goes bad when you turn in powder, the tip comes up you are trying to push the whole ski through the snow, take the bushing out and that maneuver will result in instant stall/fall.

I've noticed this.

We put a cable from back of ski to spindle so ski tip could not rise above level, magic.

I did this also!

I'm really excited to play around with the shimming and stiffer rubber. You guys are awesome, thanks for the encouragement.

 

[NEWDUCK]

Sometimes we find it best to not even use the ski while turning ? .
Also Brett, Its fairly easy to make a wood mold of what you want for a bushing/rubber. Buy a two part urethane kit and pour it yourself. I use to do small batches of urethane molding. Really easy stuff to work with and fairly inexpensive. Something like this Two part If you have a cad modeling program you can design a mold and have it 3d printed for cheap also. WE NEED MORE VIDEOS OF YOUR BUILD!

 

[Brett Kobernik]

Sometimes we find it best to not even use the ski while turning ? .
Also Brett, Its fairly easy to make a wood mold of what you want for a bushing/rubber. Buy a two part urethane kit and pour it yourself. I use to do small batches of urethane molding. Really easy stuff to work with and fairly inexpensive. Something like this Two part If you have a cad modeling program you can design a mold and have it 3d printed for cheap also. WE NEED MORE VIDEOS OF YOUR BUILD!

I had a loudmouth on a Facebook group tell me that I wasn't going to be able to turn my machine because the ski wasn't on the snow. I couldn't even engage with his level of understanding.

I'm really interested in that urethane compound. Anything else I should know about the stuff?

We are just finally getting enough snow to where I'll be able to really ride the Yamalaris. However, avalanche conditions are as bad as I've seen so this is going to limit what I can actually do. Nonetheless, we'll get some more video clips of the thing sidehilling and in deep snow soon. I'm excited to get it into the trees and see what it can do.

 

[byeatts]

I haven’t made much progress with much fine tuning but I’ve been riding the thing a lot. I’m just so tickled!!

Brett lets see some vid riding in snowbike terrain not open hills?

 

[Marty UT]

It's actually really strange for a hard core sledder that rides any motorized bike and than climb on a one ski and ride it like a bike , they have a mind set to ride it like a sled and the only thing I can figure out is that it's the snow instead of dirt or pavement , I know sounds weird .

Rode a snow bike for the first time, a couple years ago. In the beginning, I fought that thing like hell until realized I needed to ride it more like a bike. Having to shift, while I'm riding snow, felt kinda weird too!

 

[Brett Kobernik]

Brett lets see some vid riding in snowbike terrain not open hills?

Yeah, like I said, we've been starved for snow in my region and haven't been able to really get off the main roads until recently. The video was the first time this season that I cautiously got off the main roads. We'll be able to get into more terrain now that we've had a couple decent storms and some more coming.

 

[NEWDUCK]

I had a loudmouth on a Facebook group tell me that I wasn't going to be able to turn my machine because the ski wasn't on the snow. I couldn't even engage with his level of understanding.

I'm really interested in that urethane compound. Anything else I should know about the stuff?

We are just finally getting enough snow to where I'll be able to really ride the Yamalaris. However, avalanche conditions are as bad as I've seen so this is going to limit what I can actually do. Nonetheless, we'll get some more video clips of the thing sidehilling and in deep snow soon. I'm excited to get it into the trees and see what it can do.

Facebook is great for that sort of stuff!

Really all you need to know about the urethane is use a mold release spray and do not spill it. Acetone will clean up your spills but it is still a messy goo. Youll have some air bubbles in it but for your application I don't think it will matter.

Since we are pretty close to the same riding areas I figured Id ask the expert. Is that sugary base layer we have in utah ever going to settle? Seems like all these slides im seeing are 4ft plus on top of 7 inches of sugar.

 

[Brett Kobernik]

Thanks @NEWDUCK I'm gonna give that stuff a try.

That sugary faceted snow at the base of the snowpack will slowly gain some strength especially if we keep adding more snow. However, my best guess is that it will never get to the point where I consider things 100% stable. What's going to happen is as it slowly gains strength, we'll see fewer human triggered avalanches. We'll see people punching more steep slopes and not triggering anything. But it will be like having scattered landmines around. Some slopes will release, others won't and there's no way of telling which will do what.

Where are you located?