Small-Doo AMX

Ben550

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Feb 6, 2012
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Snowmobile made from scratch, apart from the track and skis, the front of the rails, there is virtually nothing that comes from an existing snowmobile.

The main goal is buoyancy, traction and maneuverability.















 

Ben550

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Feb 6, 2012
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Still snow, even if I miss my shot in a mounted, it is back and not even need to go back down, which saves the energy of the driver.

Mounted in a very narrow ditch because the snow is even softer and difficult not to overturn as the skis graze on one side and the other.






















 

Ben550

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There was a big storm at the beginning of the week, but the Small-doo stays on the surface.
The longest slope of the region on a private land that has no trace of winter (we know the owner! The coast is not technical because clear, so it's full gas the limit is the machine and not the pilot I was not sure if the weight-to-weight ratio (Snow bike) or the low pressure on the snow (Small-Doo) had the advantage (1 minute on the video)
I already had difficulties in this coast with my 153 '+ + 110hp because modified, with less snow, when it begins to dig, we need power folds, and the more power we have, the more the snowmobile is inclined. The Small-Doo has enough volume of snow to grip the surface with its caterpillar in relation to its weight to move forward without the need to project a snow tsunami behind.




https://www.youtube.com/watch?v=2vFJIYRxTCc&feature=youtu.be












 

Sheetmetalfab

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Pretty impressive psi on the snow.



Nice work.



I wonder how that sled would do with a 450 single cylinder 2 stroke from FTX Motorsports.



Contact them for further information.
 

Ben550

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Thanks,

The 450 2 stroke engine of this snow bike is placed further back than on a normal snowbike, it must give more traction initially than a YZF450 whose driver and engine are in front of the track. I found a similar engine:

It seems well done and it has everything ready for 100HP !, directly compatible on a CRF450R.
https://www.pantheramotorsports.com/us/



I evaluated different engine to put in the Small-Doo, the simplicity of industrial engines has the consequence of giving the lowest possible weight on the snowmobile. (They also more affordable) I am however close to the limit of HP possible on an engine block that is designed initially for only 17hp, (but in continuous) It is always more fun to have more power, but with the industrial engine I have the best buoyancy possible with enough power to do the job. The second best choice, (but much more expensive) would be a 4t 450 dirt bike, I would like it to be possible to remove the manual transmission to put a CVT.
 

Ben550

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Feb 6, 2012
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The weight of an engine and all that has to come around is not only connected to the engine or to the 4-stroke type. The number of cylinders and the complexity of the engine counts more.



My little 4-stroke engines are very simple, no need to add a lot of parts needed for its operation around. A sheet metal duct does well as an exhaust system given the low engine revolution. A 2-stroke needs a large calibrated exhaust system, if you keep only the tune pipe, it's tiring not bad. I did not even add the weight required at the front of the chassis to cover the bulky exhaust system. A 550 needs more than 6 liters of gas to drive at least 4 hours continuous, no choice to consider this factor, unless you turn around the cottage, the gas can already ready, are not worth closing the plug.

In the end, the only one that is comparable in weight is the 277 Tundra (possible to mount the HP, but then no torque and very noisy) And if you want to get your hands on one of these engines (especially with RER) You have to buy a complete Tundra, it's far too rare a complete engine alone.













The engine MEGA (Australia) and Le Panthera (Quebec) are 2 beautiful exotic engines big single cylinder 2t. They are very expensive and not certain of their reliability, but an unlimited budget can be.

The MEGA has no 12volt output, (no light) the output of the crank is too small to put a CVT clutch.



With the Pantera (engine designed to fitter in a bike CRF450 or MTB TRX450R), I would need a training system more solid (heavier) to support the power (not added in the table) he would need to a new base to fit a CVT clutch, which would remove gears (and weight), would compensate for the added strength of the drive system. But it's a crazy project $$

Rendered that weight, as well put a Rotax 600 first generation (110hp) as in my MXZ, which was much lighter than a 600Etec (800 base and full of components). The 600Rtec consumes just a little less than the 600 carb of the years 2010+. The 600CARB can work with gas mixer, not the Etech which needs a tank of eight and all the hardware.

New technologies have a weight and a price, they invent a lot of things to remove weight, but it does not compensate for all the components that are added.



With a 600, That would give a Small-Doo whose weight is getting dangerously close to my lightening MXZ, an anvil of 390lbs dry. It's 90lbs of difference dry for dry in addition (30% more weight on the skis) Of course that the report power weight is higher with almost 3 times more HP, but the flotability, the capacity to stop and to leave again anywhere is not even comparable.
 

Sheetmetalfab

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Thanks,



The 450 2 stroke engine of this snow bike is placed further back than on a normal snowbike, it must give more traction initially than a YZF450 whose driver and engine are in front of the track. I found a similar engine:



It seems well done and it has everything ready for 100HP !, directly compatible on a CRF450R.

https://www.pantheramotorsports.com/us/







I evaluated different engine to put in the Small-Doo, the simplicity of industrial engines has the consequence of giving the lowest possible weight on the snowmobile. (They also more affordable) I am however close to the limit of HP possible on an engine block that is designed initially for only 17hp, (but in continuous) It is always more fun to have more power, but with the industrial engine I have the best buoyancy possible with enough power to do the job. The second best choice, (but much more expensive) would be a 4t 450 dirt bike, I would like it to be possible to remove the manual transmission to put a CVT.


Fastrax Motorsports motor is a fully developed single cylinder cvt motor.

90 hp cvt. (The only one in the world I know of)

 

Ben550

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Feb 6, 2012
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Fastrax Motorsports motor is a fully developed single cylinder cvt motor.

90 hp cvt. (The only one in the world I know of)
Very interesting engine for a light snowmobile!
I only found it on Facebook, and it seems to have been made to a single copy, engine machined.

I had not considered a snowmobile 4 times before making me (because there was nothing light) but the more I roll with the more I appreciate the idle only at 1300RPM and the strong torque has only 3000RPM, unlike the 2 stroke that stuffs when you roll slowly.

It would be wonderful to build another Small-Doo with this 450 2-stroke engine, I doubt it should cost a fortune
 

Ben550

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Feb 6, 2012
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I was able to compare with the ski-doo snowmobile that has the lowest ground pressure among all. A SWT 550 2007, 610lbs dry is the least heavy of the 24 '' that has been manufactured.
I would have liked to have more difficult snow conditions, but still a lot of snow with a crust that breaks easily as soon as the trackr skates.
The Small-Doo would be moreTundra category because can not do heavy towing, but the new Tundra is so much back side buoyancy and traction, that it does not bother to compare. The 20 "and 24" hybrids that can make the trail (this is not the case of the SWT550) have lost some of their buoyancy and reverse performance(weight on the front).
Several tests of reverse at low speed on a slight upward slope so the inclination increases rapidly and the amount of soft snow also increases more and more. The Small-Doo is always made further but without declassing the SWT which is excellent.

In uphill climbs (impossible to test on the board, this would require crazy conditions for the Small-Doo or SWT to stop moving forward). The Small-Doo can stop and restart where the SWT has stopped climbing. himself. I took care to approach the slopes slowly in 2 cases to give equal chances, with more experienced and less experienced pilot exchange.

Ground pressure of SWT 550 2007 with pilot = 0.47lbs / in2
Small-Doo AMX ground pressure with pilot = 0.37lbs / in2
Small-Doo X ground pressure with pilot = 0.50lbs / in2

This figure, which nobody is looking at, is very revealing, especially for the crossing capacity at less than 50km / h on no solid bottomless snow. At high speed, the power and the pallets can take over, but in full wood it is rather at risk.


https://www.youtube.com/watch?v=WRLCBuv8Mjw&t=122s




 

Ben550

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Feb 6, 2012
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Ryde Small-doo AMX and Small-Doo X together. Each with a track end (174-120). Better to have 2 different snowmobiles than 2 same. The Small-Doo X asks to keep a higher speed to climb the side, the difference would be even more marked if there was a greater amount of fresh snow.

The first rib (which I have hardly used this winter to keep it soft) I probably would have been able to mount it the first time with the Small-Doo AMX. After digging a hole in the side, it is difficult to cross the hole because the exit angle of the hole adds to the angle of the slope to put the snowmobile upright. The coast goes down well from the back even without gearing the reverse, the track with the brake slips down ... A small difference in driving experience still allowed me to climb the coast with the 120 '' first.




The Small-doo X shorter and a little lower, behaves like a gokart in narrow and winding small ways, consumes very little, it gives the impression of driving a motorcycle on hard snow so its rolling friction is low , need the brake otherwise it will not stop. The Small-Doo AMX still behaves better than my MXZ 153 in small winding roads. (rotates more easily with less effort) It is less stable laterally due to the long unwrapping of the air suspension (which aids maneuverability in deep snow)

The Small-Doo AMX can stop and restart in a 30-degree climb, without digging a 5-foot trench, quite unique.




https://www.youtube.com/watch?v=kTE3xqMrsAA

Small Doo X and Small Doo AMX
Small Doo X and Small Doo AMX
www.youtube.com











 

Ben550

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Feb 6, 2012
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Probably a last little tour.

At +17 degrees C (63 F) the snow is in liquefied salt a bit like slutch. But it does not sink, can still stop and start again up hill.




 
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