Author Topic: Homemade diy snow dog tracksled build help  (Read 866 times)

Offline Cortland15b

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Homemade diy snow dog tracksled build help
« on: Mar 21, 2020, 06:10 PM »
Hello everyone, I just traded a old trailer axle for the guts from a 92ish skidoo touring and I donít know what the heck Iím doing. I have mechanical skills, welder, automotive experience working on cars, electronics degree, tools and a heated garage but donít know a dam thing about snowmobiles. I never had them growing up and I can count on one hand the times Iíve even ridden one.

I apologize in advance the names that I call components because I donít know so please correct me.

With that said I have the tunnel which is separated from the suspension which I want to use instead of building my own frame, a track thatís in pretty good shape but not terribly tall lugs, the rubber driving cog, the chain case which the guy says has reverse and the brake is on that as well. On the opposite end thereís a pulley wheel. Track is 16 1/2 inches wide and is a bombardier p1570-2033 which I found on eBay saying itís 124Ē long.

Iíve read almost every diy thread Iíve found but Iím a noobie so I still have questions.

So I think the parts I need are a 30 or 40 series torque converter. What exactly is the difference? Are there any one options out there? Whereís a good place to buy this stuff? I saw a nice blue homemade snow dog that looked like it had a chain going directly from the engine to the drive sprocket but I looked closer and thereís some type of gearbox hooked to the engine first but itís not a torque converter. What is it? I think it might be metalbenders 2nd build but Iím not sure.

Iíve read gearing is an issue and I need the biggest gear I can fit somewhere around 72 teeth to get the best ratio and not run it hot and burn up belts. Where is this gear actually at? Is this the gear that replaces the big pulley wheel on the opposite side of the shaft across from the chain case? Why do they use a chain here and not the pulley already on the snowmobile?

Iíd be looking at the predator engines. What engine do you think would be the smallest I should go so I know where to start? Thinking 8-10 hp models. I saw someone on YouTube just use a 6.5 hp model, how would that be? I donít know if I can shovel out the money for the 13.5 hp model though itíd be nice. Maybe if I can get a deal on one. How about the Briggs & Stratton CR950? 200$ doesnít seem bad for 9.5 hp.

Iím not wanting to shorten the track but may consider it. To get passed any turning issues the longer track may give me I plan on having a pretty long handle to give me more leverage.

Thanks in advance. Pictures to come.

Online MTJ

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Re: Homemade diy snow dog tracksled build help
« Reply #1 on: Mar 21, 2020, 06:23 PM »
I don't have any experience with these but of you search "diy snow dog" on YouTube there are plenty of videos. One of the videos uses a predator engine but I am not sure what horse power it is.

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Re: Homemade diy snow dog tracksled build help
« Reply #2 on: Mar 21, 2020, 06:34 PM »
The difference in 30 and 40 series torque converter,one is for lighter duty and smaller engine hp and the 40 is heavy duty and for larger hp motors.the big gear will go where the large pulley is on the sled.i have not built one yet but i will be using a predator 6.5 engine to power mine and should be fine if geared right.electric start would be nice on the larger predator engines.i have everything to build one but the snowmobile drivetrain sitting here because i build alot of old school minibikes.

Offline Cortland15b

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Re: Homemade diy snow dog tracksled build help
« Reply #3 on: Mar 21, 2020, 06:52 PM »
The difference in 30 and 40 series torque converter,one is for lighter duty and smaller engine hp and the 40 is heavy duty and for larger hp motors.the big gear will go where the large pulley is on the sled.i have not built one yet but i will be using a predator 6.5 engine to power mine and should be fine if geared right.electric start would be nice on the larger predator engines.i have everything to build one but the snowmobile drivetrain sitting here because i build alot of old school minibikes.

Nice! Hopefully you post pictures as you go along. What made you decide on the 6.5 hp motor? Iím guessing youíll be using the 30 series clutch with that size engine?

Offline Cortland15b

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Re: Homemade diy snow dog tracksled build help
« Reply #4 on: Mar 21, 2020, 06:57 PM »
Just remembered another question, most guys I see take out the springs and ďlowerĒ the track somehow.

Why do they take out the suspension springs and make it a solid suspension? What advantages does that have?

How do they lower/level/ flatten the track?

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Re: Homemade diy snow dog tracksled build help
« Reply #5 on: Mar 21, 2020, 08:06 PM »
Nice! Hopefully you post pictures as you go along. What made you decide on the 6.5 hp motor? Iím guessing youíll be using the 30 series clutch with that size engine?
ive already got a few new predator 6.5 engines.also tecumseh and briggs laying around.yeah im starting with 30 torque converters just because i have them too.think you remove the suspension for better steering and traction.i did get a 1990 arctic cat cougar sled for free last week but it is still decent and i had it running already so im still looking for a drivetrain for a snowdog.i have all the other parts here except the primary drive sprocket.

Offline Cortland15b

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Re: Homemade diy snow dog tracksled build help
« Reply #6 on: Mar 21, 2020, 10:00 PM »
ive already got a few new predator 6.5 engines.also tecumseh and briggs laying around.yeah im starting with 30 torque converters just because i have them too.think you remove the suspension for better steering and traction.i did get a 1990 arctic cat cougar sled for free last week but it is still decent and i had it running already so im still looking for a drivetrain for a snowdog.i have all the other parts here except the primary drive sprocket.

How many tooth sprocket are you thinking of going and whereís a good place to get those? Iím considering the 6.5 predator and 30 series just cause of the cost factor. Do you plan on shortening whatever suspension you end up using or leaving it stock?

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Re: Homemade diy snow dog tracksled build help
« Reply #7 on: Mar 22, 2020, 06:53 AM »
How many tooth sprocket are you thinking of going and whereís a good place to get those? Iím considering the 6.5 predator and 30 series just cause of the cost factor. Do you plan on shortening whatever suspension you end up using or leaving it stock?
probably the biggest sprocket i can find.i have tractor supply or get one online thats for minibikes.72 tooth probably good.might have to make a key way in the shaft of sled to hold the sprocket on.far as suspension goes i will probably just level it off.if its a older sled that doesnít have shocks i will leave it.some old sled  have wire springs with no shocks for suspension.if it has shocks just replace with steel square tube.

Offline metalbender

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Re: Homemade diy snow dog tracksled build help
« Reply #8 on: Mar 22, 2020, 12:03 PM »
A bit of advice, don't take out the suspension.  Mine's a tad soft, crashes pretty hard on short drifts. I have heavier springs, just haven't installed them yet. Don't go less than the 9.5 hp, better to have enough grunt than push the darn thing. Lots of good info on building, couple of nice ones using a sled tunnel. The two I built were done with sq tube.

Offline metalbender

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Re: Homemade diy snow dog tracksled build help
« Reply #9 on: Mar 22, 2020, 12:22 PM »
A couple of pics. Small one is 6.5 hp, bigger one is 13.5hp, elct start, also wide track.




Offline Cortland15b

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Re: Homemade diy snow dog tracksled build help
« Reply #10 on: Mar 22, 2020, 02:17 PM »
A bit of advice, don't take out the suspension.  Mine's a tad soft, crashes pretty hard on short drifts. I have heavier springs, just haven't installed them yet. Don't go less than the 9.5 hp, better to have enough grunt than push the darn thing. Lots of good info on building, couple of nice ones using a sled tunnel. The two I built were done with sq tube.

What do you recommend using for the clutch function, 40 series torque converter and something different? Right now the cost of the 40 series has me wanting to do a 6.5 predator engine and keeping the hp within the rating of a 30 series.

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Re: Homemade diy snow dog tracksled build help
« Reply #11 on: Mar 22, 2020, 02:35 PM »
From my use of torque converters on minibikes the comet clutch series are real nice and reliable but cost big $$$.ive been using the cheap china ebay torque converter systems that are around 50$ and get a spare belt but i have not burn up a belt or burnt a torque converter clutch up yet on minibikes or go carts.if geared properly a 6.5 and 30 series should work.gear it low for power as speed is not needed for pulling ice gear.if geared to high it will burn the belt and clutch up just like a mini or kart.

Offline XN

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Re: Homemade diy snow dog tracksled build help
« Reply #12 on: Mar 23, 2020, 06:49 AM »
I used the tunnel, track, and gear box on the one I built. Had an 8hp HF motor on it with a ebay knockoff 30 series knockoff clutch on it. My gear box was around 3:1 so it worked well with gear that came with the clutch. I used a 10 tooth on the clutch output and something around 21 tooth on the gearbox input. I was geared a little high an it would do 30-35 mph, really too fast.
https://www.ebay.com/itm/COMET-TORQUE-CONVERTER-30-SERIES-GO-KART-KIT-CLUTCH-1-30-75-10T-40-41-M-CT25/232259598071?hash=item3613c036f7:g:ZIQAAOSwnVVZpf9L

I took out the suspension out of the track.

My biggest problem with mine was I had too much flex between the motor and the gear box mount so my chain would flex and skipped teeth under high load situations.

With all the high performance parts for the 6.5 hp motors you may want to hop one up and use that. It will be lighter and your cost may be similar to going with a larger motor.
http://www.nrracing.com/product-p/stage2hopup-ph.htm

Offline Cortland15b

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Re: Homemade diy snow dog tracksled build help
« Reply #13 on: Mar 24, 2020, 12:34 PM »
Hereís the photos I took after I cut some stuff off. Ran out of cutoff wheels for my grinder so I had to stop plus it was before I picked up the suspension and gearing and driveshafts so I didnít want to cut too much off either. I want to try and modify that front tubes to make some kind of bumper, shorten it or move it rearward somehow.


Iíll need help getting the chain case back together itís all in pieces in a box. Are there torque specs to follow and I heard that you should use locktite on the bolts. Any guidance would be appreciated Iíll take some photos next time I work on it

Offline Cortland15b

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Re: Homemade diy snow dog tracksled build help
« Reply #14 on: Mar 24, 2020, 12:38 PM »
















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Re: Homemade diy snow dog tracksled build help
« Reply #15 on: Mar 24, 2020, 12:39 PM »
 as far as the chaincase goes its a maintenance area and i would not use locktight on any of it.make sure the chain tightener is set right  or chain too loose will skip and 2 tight will break.i would remove all those bars upfront.keep it light as possible.this snowdog is not mine but has the simplicity on how i will make mine.


Offline Cortland15b

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Re: Homemade diy snow dog tracksled build help
« Reply #16 on: Mar 25, 2020, 09:05 AM »
Thatís a nice simple design but it looks like the engine is off to one side too far cause they used the original position of the belt pulley wheel. Move that to the center or counter weight it somehow and itíd be a good machine. Iíve debated using angle iron to make a box around the tunnel or go with a tubing cage that would protect the cargo if it tips over.

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Re: Homemade diy snow dog tracksled build help
« Reply #17 on: Mar 25, 2020, 09:11 AM »
Right but i plan on building a rack on back of tunnel and can load gear and balance it out.a 6.5 engine with torque converter is not major weight and should balance decent with the original chaincase and brake system on the other side.idk see when i get a doaner snowmobile.i also have electric start briggs motors and can offset weight with the battery.using the middle of shaft you will have to cut the tunnel and risk the big sprocket rubbing on the track.im sure there is flexibility on primary gearing tho considering its geared from the original sled drivetrain.similiar to jackshaft gearing on minibikes.

Offline Cortland15b

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Re: Homemade diy snow dog tracksled build help
« Reply #18 on: Mar 25, 2020, 08:13 PM »
I saw the build thread of the guy who made that sled I think his user name is team rapo heís on here but the thread I saw was on another forum. I see the simplicity of the design and didnít think about the crank case being the counter weight plus maybe a battery or a gas can to balance it out as well. Iíll definitely look into it. He said he tried 3 different engines to balance it the best and he settled on a 7hp engine and a 72 tooth gear and a 30 series.

What would happen if you used a centrifugal clutch like this straight to a 72 tooth gear instead of the torque converter?

https://m.northerntool.com/shop/tools/product_200310374_200310374


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Re: Homemade diy snow dog tracksled build help
« Reply #19 on: Mar 25, 2020, 08:49 PM »
I saw the build thread of the guy who made that sled I think his user name is team rapo heís on here but the thread I saw was on another forum. I see the simplicity of the design and didnít think about the crank case being the counter weight plus maybe a battery or a gas can to balance it out as well. Iíll definitely look into it. He said he tried 3 different engines to balance it the best and he settled on a 7hp engine and a 72 tooth gear and a 30 series.

What would happen if you used a centrifugal clutch like this straight to a 72 tooth gear instead of the torque converter?

https://m.northerntool.com/shop/tools/product_200310374_200310374
you will burn it right out.they get real hot even running on minibikes.i get about a year on one when geared right and jackshaft gearing is right on small minibikes turning 4 to 6Ē tires.by the time rpm gets enough to start the clutch it will get hot and wreck the springs inside.those are for light duty only.my ice minibike has that on it and it gets jerky and very hot in a few minutes.it does about 28mph.i have the exact same mini with torque converter is smooth power and does 50 with no heat.torque converters you get more torque with the smaller engines.jmo.a centrifugal clutch wont turn the track and if it did not for long and being stranded with a track sled would suck to push or pull back to the truck.

Offline metalbender

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Re: Homemade diy snow dog tracksled build help
« Reply #20 on: Mar 25, 2020, 09:51 PM »
My first sled had a double reduction using a simple clutch.  Even at that it was smokin' hot most of the time. Second one I used a 2-1 reduction gearcase with built in clutch. This is a multple disc unit running in oil. Works good but I give it lots to start with to set the clutch.

 



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