Finally, a Snowbike Exhaust Cooker! (And complete custom CVT bike)

[egesledder]

I'm curious; what diameter and wall thickness was the chromoly you used to build your tube frame?

Very nice build.

It depends on the location, I used a variety of 3/4" and 1" OD tubing with either .049" or .035" wall thickness. I think one section was actually .028", but I'd have to look back through the design.

A future build will be completely chromoly without aluminum side panels. The panels actually add a lot of unnecessary weight. It gets tricky though since the panels make a nice alignment datum.

 

[mrquick68]

Yep, after looking at the clutches, they're only shifting half way out and they're definitely upshifting too fast based on the riding I did. Something isn't right in there, but I've got a full clutch kit coming for it and all new bushings for everything.

And yea, its a 600HO motor with a fresh top end, so it should pull quite a bit harder than it is right now with proper clutching.

Colorado is getting hammered between now and this weekend, so deep snow is coming!

Cool build! how far your clutches shift out is in many ways a function of speed, never gonna shift out all the way unless you get that mother on trail going 80mph+, UNLESS you gear it down. My guess is its likely geared too high, and/or you have too shallow of a helix. what you are looking for is: peak RPM in a climb (8300?), under full load in 18" of snow or so, WOT, and the clutches at about 1:1 in ratio (where they are most efficient). you can confirm this using a black pen and see how far it shifts out in that specific scenario.

should be a fun project to watch. It's gonna be hard not to have a snow-hawk like product in the end with a motor that size though. I'd like to see some more discussion on packaging. You've got a lot. Is a 600CC twin pipe that much bigger than a 500CC single pipe? Does it really need to be a CVT, or is there another option?

 

[egesledder]

Cool build! how far your clutches shift out is in many ways a function of speed, never gonna shift out all the way unless you get that mother on trail going 80mph+, UNLESS you gear it down. My guess is its likely geared too high, and/or you have too shallow of a helix. what you are looking for is: peak RPM in a climb (8300?), under full load in 18" of snow or so, WOT, and the clutches at about 1:1 in ratio (where they are most efficient). you can confirm this using a black pen and see how far it shifts out in that specific scenario.

should be a fun project to watch. It's gonna be hard not to have a snow-hawk like product in the end with a motor that size though. I'd like to see some more discussion on packaging. You've got a lot. Is a 600CC twin pipe that much bigger than a 500CC single pipe? Does it really need to be a CVT, or is there another option?

Thanks for the info, its helpful. I'm re-learning clutching after being away from it for a while. I'm working with Joey (dynamojoe) to get a start for the clutching. Gearing down is definitely in the works, its too high right now. Timbersled sprockets don't go low enough, so I'm modifying some standard gears from Mcmaster to fit. Looks like it should work well.

As far as this versus a snow hawk, its a heck of a lot smaller feeling than any hawk I've ever been around. The weight is also further back. It honestly doesn't feel that different than a standard bike conversion, except with a lot more power and better noise. I'll be working on more weight reduction and more compact layout on the next one, there are still lots of areas for improvement with this first one.

A CVT makes snow riding a lot easier than shifting gears due to all the quickly changing conditions you encounter. If you can figure out another option than can accomplish the same thing, that would be a big deal. Maybe a hybrid turbo 2-stroke / electric motor?? Haha

 

[mrquick68]

sounds really cool! I totally agree on the functionality of the CVT, my issue with CVTs is their size, power loss, as well as rotating mass. i agree they are work better in snow though. Just wonder if they can be moved, or made smaller?

 

[Sheetmetalfab]

Thanks for the info, its helpful. I'm re-learning clutching after being away from it for a while. I'm working with Joey (dynamojoe) to get a start for the clutching. Gearing down is definitely in the works, its too high right now. Timbersled sprockets don't go low enough, so I'm modifying some standard gears from Mcmaster to fit. Looks like it should work well.

As far as this versus a snow hawk, its a heck of a lot smaller feeling than any hawk I've ever been around. The weight is also further back. It honestly doesn't feel that different than a standard bike conversion, except with a lot more power and better noise. I'll be working on more weight reduction and more compact layout on the next one, there are still lots of areas for improvement with this first one.

A CVT makes snow riding a lot easier than shifting gears due to all the quickly changing conditions you encounter. If you can figure out another option than can accomplish the same thing, that would be a big deal. Maybe a hybrid turbo 2-stroke / electric motor?? Haha

Narrowing it up between your thighs will be huge for body English.

 

[fordpickupman]

Great job!

This is an awesome build! You've got me eyeing my wife's old 700 RMK as an engine donor.

 

[Sheetmetalfab]

This is an awesome build! You've got me eyeing my wife's old 700 RMK as an engine donor.

The rotax 600 motor is 10# lighter and 3" narrower. Fwiw

 

[egesledder]

Lots of updates since the last time:

-Completely custom belt drive setup, see pics

-Custom Dynamo Joe clutching. He wasn't sure where to start, but he nailed it pretty well the first time. Fast backshifting and pulls well.

-Dirt Labs shock revalve and new springs. Luby at Dirt Labs revalved the stock '14 Timbersled shocks. Stiffer rebound and compression on both, more on the front. Went from the stock 200lb spring in the front to a 300lb spring. Fork got .60 springs and 20wt oil. This thing handles awesome now, and can do 4-5 foot drops at speed without bottoming.

-Jetting is getting closer. The stock trail sled jetting was waaaay to fat.

Finally, a good hot delicious gas station burrito in the backcountry:

https://youtu.be/pow3JMmHSOE

 

[Sheetmetalfab]

Any more development?

Maybe production?

 

[egesledder]

Any more development?

Maybe production?

We're starting to swap in the 600SDI motor and reworking a few drivetrain items that wore more than I'd like to see after last season.

I have a new design finished for the next one that should shed a ton of weight, but I've got a few other projects on my plate at the moment and this one isn't one of them unfortunately. Building and racing cars is time consuming. I need to quit my day job and build stuff full time.

 

[Hawkster]

That HO should of been putting out somewhere around 115 to 118 ponies with that pipe and I think the SDI is somewhere around there stock . The electrical is a big bump too ? 480 I think ? With the correct mapping that is an excellent engine .

Let her rip

 

[J&L Snowhawk]

That HO should of been putting out somewhere around 115 to 118 ponies with that pipe and I think the SDI is somewhere around there stock . The electrical is a big bump too ? 480 I think ? With the correct mapping that is an excellent engine .

Let her rip

Do you feel the sdi is a good engine to run? Thought about one before just didn't know if I wanted to mess with all the electronics again. Will be doing 800 pro soon so begins the headache

 

[Hawkster]

It's a strong engine , it also was one of the early SDI's and they got a bad rap because of the lack of tuning compared to carbs and the whole mapping process was new and locked up like fort knox so it got shunned from everyone .

It took a couple of years before anyone could even do the mapping besides Doo and no one could even make a can that didn't rob horse power . By than the craze was the 8's since you could by one for the same price .

Good luck with the Pro , I believe that their problem was the lack of electrical with the IQ and earlier Pros , all you have to do is follow the threads to see that . Everyone made bank but the owners on those .

Hope your riding

https://www.rotax.com/en/products/rotax-powertrains.html

 

[El Gringo]

Egesledder, congratualtions on making what I think is a very well executed snowbike. While I really enjoy the dirt bike based bikes we are riding now I think that what you have built points the way to the future. Thanks for sharing your creation, I look forward to seeing it evolve and would love to see the ball picked up by others.

 

[Mendomotox]

I'm late but wow! That bike looks like a blast. I'm researching doing something similar. I have a 2008 m8 that would likely be the engine done. The 162" 2.25 powerclaw would probably be more track that nessasary even when narrowed though. I also have a 151x2 16 wide ski doo track and skid. And a 144x2 15 wide polaris track and skid that may be better suited. It seems like narrowing the track is the way that all the bikes have went. So whatever track I end up using will get narrowed to just wider than the drivers. Engine placement looks to be key, with the suzuki engine from the arctic cat the exhaust and intake are both on the front of the engine so that may make packaging easier.. or may make it worse. Will just have to wait and see there. Is the ARO ski the best option for a ski right now? Any one attempted a custom wide 4 runner ski? I've got lost of sled parts laying around. Man these winter sports are really hogging up all my spare time haha, the thought of a 150hp, efi, sub 400lb snowbike is hard to shake. The suzuki 800 really likes boost too so that could take it to 250hp. Might not be worth the weight though.