Outside the box again.....and in the dirt.

[Snaggletooth]

Well, it seems everytime one of my buddies comes up with a crazy, hair brain idea they end up coming to me. I must have a rep as a nut job to be targeted like this. Well, yeah, done some odd things myself.

 

I'm gonna need all the advise I can get on this one.

 

So here's the deal. Buddy used to hill climb Yammy Y2's that he stretched out. He's getting back into it and he's shooting to do the 600cc 2 stroke class.

 

Sounds simple right? Buy a 600cc 2 stroke and stretch it. Simple. Nope. Not this guy.

 

He's found a sled engine, a Rotax 570 that pushes 105 hp. He's got a couple of frames that it will fit into nicely.

 

The deal is.....the drive system is the dual centifigul clutch/pulley set up from the sled. Get the picture?

 

So.... the drafting of a plan is on the board to find a way to go to a single clutch/belt drive to more than likely a jackshaft to convert to chain drive to the rear wheel. In my mind....too much HP would be lost through a jackshaft setup. Not to mention the issues of tenisoning the belt from clutch to jackshaft.

 

My thought is to use a single notched belt from the centrifigul clutch to a notched hub pulley on the rear wheel. Tension adjustment would be simpler and less power loss.

 

Now I might mention the last time I messed with centifigul clutches was when I built my first mini bike.

 

I see this working but it's going to take some creative engineering to pull it off. But like it has been said here before......Nothing is impossible.

 

Anybody care to throw some ideas out this way?

 

Mike

Edited December 5, 2010 by Snaggletooth

[dingy]

Does the clutch have notching on it that will match a notched belt? If clutch is not notched then you can't use a notched belt. There would be less than 50% contact surface area between a notched belt and an non notched pulley, which would slip for sure.

 

Gates has a wide selection of notched belts & pulleys I have used quite a bit on conveyor designs. Also have hub sizes to fit about any standard shaft.

 

http://www.gates.com/index.cfm?location_id=534

 

Gary

[oldgoat]

call me dumb but why not go with a belt driven rear wheel?

once the engines clutch grabs the belt it will power the wheel?

[friesman]

Go look at a snowmobile setup. the clutches have come a long way in the last decade or so. I used to run Kevlar notched belts in my Yamaha sled all the time, as the clutch face is tapered and the belt grips on the sides, not the inside of the belt. Yamaha also used a variable sheaves on the track end of the belt to give contsant variability and torque and engine speed.

 

I also used to put heavier weights inside the clutch to give higher stall speeds, with the heaviest weights my old EX440 would not move until it got to 5000 rpm then it was like dropping the clutch.....hard! you couldnt leave a stop without both skiis at least 2 feet in the air

 

Brian

[Snaggletooth]

Gary had a good point. Unless the clutch has a cog drive the belt is limited in contact footprint. I do need to see the centifigul from the old sled to see if it can be used.

 

Brian, I've seen some of the new sleds set up for racing and they do hook up rather nicely. LOL! Maybe I can find some local sledders to take a look at how they are set up.

The high stall would be great in this this application.

 

I did run across the http://www.revloc.com/index.cfm/id/14/Revloc-Clutch/ website. They have several choices on centifigul auto clutches that are used in dirtbike setups. Going to be looking into that. Maybe they have something that can deal with 100 HP.

 

If I can find a centifigul auto clutch that has lockup, the ability to change the weights, a replaceable chain sprocket, and can deal with having 105 HP dumped on it.....this may work without breaking the guys bank.

 

I mean afterall.....how hard can it be? All he needs is idle and GO! GO! GO!

 

If this works out, maybe I'll set him up with a 1/4 turn throttle. That should make it fun to ride. :rotf: