Winter fun - Project “Freedom” 440cc 2 Stroke 1054 Snowmotractor

[Pullstart 62,848]

15 minutes ago, Blasterdad said:

#40 roller chain & sprockets? Maybe bigger...#50-60?

I had that setup, but it wouldn’t clear the axle casting in the rear.

[Pullstart 62,848]

20 minutes ago, Wild Bill 633 said:

@PullstartFYI, 2 strokes need very good compression. I think the reason the engine will not start on the first pull is compression. Most likely needs refurbished cylinder walls, pistons and rings.

now that it has fuel, it starts in one or two pulls 

[Pullstart 62,848]

Hopefully one of these works.  

[Pullstart 62,848]

Hopefully one of THESE works..

 

I’m losing snow fast!

[The Freightliner Guy 1,327]

1 minute ago, Pullstart said:

Hopefully one of THESE works..

 

I’m losing snow fast!

ow i know that all to well snow melted so fast i didnt have much time to ride my 99 xcr 120

 

Kollin  

[Pullstart 62,848]

Third trip’s a charm?  15430 too big.  15420 too small.  There’s a 15423 and 15425.  Ugh.

[Handy Don 12,217]

Alternate to the chain drive might be cogged belt and pulleys?

Hoping for another snowstorm for you!

Edited February 7, 2023 by Handy Don

[Handy Don 12,217]

Realized that at the relatively low RPM and modest belt wrap on that small pulley, getting it to handle the torque is gonna be a challenge.

[Pullstart 62,848]

3 minutes ago, Handy Don said:

challenge

My biggest yet… has been convincing the arrogant man at the local AutoZone that he can get me a belt without a vehicle application.  The next town over, they are super nice.  The closer one, not worth the trip.  

[8ntruck 6,999]

Got room around the small pulley that is slipping for another belt tensioner?  Position it near the small pulley to get more belt wrap around it?

[Pullstart 62,848]

15 minutes ago, 8ntruck said:

Got room around the small pulley that is slipping for another belt tensioner?  Position it near the small pulley to get more belt wrap around it?

I intended for that.  The larger pulley next to the small one is limiting the distance I can be from the pulley.  I’m beginning to believe I need to have one more jackshaft and a final chain drive it I can get one to fit.

[wallfish 16,995]

Try putting a idler pulley close to that small pulley and get as much belt to groove contact as possible. If you put it on an arm, swivel at the end mounting point and make it adjustable with a bolt you can crank it tight.

On the bike, it's even a smaller drive pulley but that's what ended up working. Super tight cogged  belt rigid idler close to small pulley but the belt tension is done at the rear tire, so may be worth a try.

Or do something to space the trans back to tighten the belt with a rigid mounted idler. Like studs in the trans and nuts to adjust and lock down???

Just throwing more $&!t to see what sticks

 

 

Edited February 7, 2023 by wallfish

[Pullstart 62,848]

@wallfish My thoughts, are maybe another shaft?  Maybe even go chain drive then?

 

 

[Pullstart 62,848]

Part of my issue @wallfish and @8ntruck is that a belt loose enough to allow the pulley to be installed (I have to remove the rear pulley, slide the belt on, install the pulley) will touch when compressed.  The one on it now, 15425 I believe, was so tight that it was all I had to get the pulley back on.  It still slips.  I just don’t think the pulley has enough surface area.

 

I have room inside the frame for one more belt.  One more jackshaft.  One more set of bearings.  I’m essentially building a belt drive transmission!  I thought about chains, but I think the belts will work if I have one more small reduction set.  With larger pulleys and more surface area, that is!

 

The first v belt pulley is spinning the fastest and so far is not slipping.  It is 2.85” and a I have not had an issue (yet) with it feeding the 4.95”.

 

This one is 2.25” and slips like crazy even though it’s 43% slower.  The extra 1.88” circumference must mean the world of difference!

 

 

I am also fighting cold oil and internal resistance inside the transmission.  I believe the belt slip might be the simple resistance of the trans is greater than the grip of the belts.

 

I am gaining confidence in this s additional jackshaft idea.  If it still does not perform well, my next plan will be to gut the transmission of any unused gear set internals.

 

Edited February 8, 2023 by Pullstart

[Wild Bill 633 845]

@Pullstart The speed of a v-belt is usually 2500-7000 FPM. A speed of 4000 FPM is ideal. Chain drives are used at lower speeds with higher torques. If the belt speed is less than 1000 FPM, consider a synchronous belt or chain.

Edited February 8, 2023 by Wild Bill 633

[Pullstart 62,848]

I ordered more stuff from Zoro today.  It might be a lost cause.  Now, the first v belt pulley will be vulnerable to the least amount of grip.  Hopefully it will prove to be enough, with the addition of another jackshaft.

 

 

I’m not sure if I’ll need to move the current jackshaft, due to the brake disc I built, or if it’ll all work out.  

 

 

[8ntruck 6,999]

What is the pulley diameter on the brake shaft on the setup that was slipping?  Looks like you want an input speed of about 700 rpm.  With that diameter, we can check the belt speed in ft/min.  If the belt speed is within cog belt guidelines, that is a possible solution instead of another jack shaft.

[Pullstart 62,848]

33 minutes ago, 8ntruck said:

What is the pulley diameter on the brake shaft on the setup that was slipping?  Looks like you want an input speed of about 700 rpm.  With that diameter, we can check the belt speed in ft/min.  If the belt speed is within cog belt guidelines, that is a possible solution instead of another jack shaft.

It’s 2.25” 

 

My Zoro order is on the way, and I’ll have another jackshaft on Monday.  Snow is gone, so for the time being I’ll be waiting in anticipation, or with the training wheels on the front.

[8ntruck 6,999]

The belt speed on a 2.25" diameter pulley running at 700 rpm is 412 ft/min.  A cog belt should work in this situation.

[Pullstart 62,848]

8 hours ago, 8ntruck said:

The belt speed on a 2.25" diameter pulley running at 700 rpm is 412 ft/min.  A cog belt should work in this situation.

I believe you, but I think the drag in the transmission is hard to overcome, plus the grip of the tires and the weight of the machine as well.  I really hope that adding this extra jackshaft, some larger diameter reduction pulleys and more surface area, will all help make it into an unstoppable beast!

[Pullstart 62,848]

I reduced a lot of parasitic drag today!

 

 

[Handy Don 12,217]

7 hours ago, Pullstart said:

I believe you, but I think the drag in the transmission is hard to overcome, plus the grip of the tires and the weight of the machine as well.  I really hope that adding this extra jackshaft, some larger diameter reduction pulleys and more surface area, will all help make it into an unstoppable beast!

The critical measure of slipping is the friction--normal force, coefficient of friction, and area. A small pulley just doesn’t offer enough area with sufficient friction to transmit the needed power--especially since you cannot really tighten the belt sufficiently. Yes, there is a lot of drag and inertia to be overcome within the transmission since those shifting gears would have to accelerate a lot due to the brake shaft input IF THEY WERE ENGAGED. But since you had the trans in neutral, they weren’t turning!

Echoing @8ntruck, cogged belt and pulleys in the final drive seems like a simpler solution than more shafts, belts, and bearings.

Edited February 9, 2023 by Handy Don

[The Freightliner Guy 1,327]

isnt the snowmotractors engine from like a 94 polaris indy 400 or 500 it sound familiar.

[Pullstart 62,848]

1 hour ago, The Freightliner Guy said:

isnt the snowmotractors engine from like a 94 polaris indy 400 or 500 it sound familiar.

Indy 440 yes.  I’m not positive on the year, but you’re close.

[Pullstart 62,848]

@Handy Don I realize that not just one thing is the issue.  The small pulley is out of the question, it’ll be removed soon.  The brake shaft still spun other gears and shafts, or at least one more.  There is even the drag from the oil it slings, and the grip that the oil had on the other gears too.  It’s like if you start a gear drive with the tires off the ground, and it’s in neutral, the axles still move.  
 

My extra pulleys for the last jackshaft arrived today.

 

 

Edited February 9, 2023 by Pullstart