New vari speed tranny build

[wayne z]

Ahhh, COOL!
The sparse info Harbor Freight had didn't mention it had a governor on it, that would explain a great many questions I had when I looked into the motor yesterday.

One thing I did find answered from the sparse info is why you didn't just use a SBP shift kit and bike gears though, with the motors cylinder facing backwards there just isn't enough room to Jackshaft it over to the right.

Spiffy creative work there WZ, very cool.
My limited experience with 4-strokers is if you can get it off the line in a hurry like a geared 2-stroke and then walk away from them with a shift at 30 or so you'll have one heck of a sweet ride ;-}

Hey KC ,thanks. I never considered using a SBP jackshaft and derailer shift ect. I figured that stuff ain't up to the heavy duty power pulses of a 4 stroke and wouldn't be reliable. too many light weight moving parts. With a belt primary and secondary, there is slight slippage that eliminates the damage from torsonal viberation which is worse with a 4 stroke cuz they fire every other rev.

 

[wayne z]

OK, I mocked up the housing in wood today. The final shape will be similar to what is drawn on the outer plate.
I did some layout geometry and estimate that the idler will have to have nearly 6 inches travel to mash the belt enough to complety actuate the vari-pulley! Might hafta go to the jockey shift. I don't know if I can get a hand clutch lever to work with that much movement, but I'm gonna find out.

 

[cannonball2]

Possibly a scissor hinge like we lift the engines with on the direct drive FDs? The normal lift can be nearly three inches with a hand lever depending how you configure the hinge. That is starting with the hinge closer to vertical. What if the hinge was pulled in reverse closing it instead of opening it? Maybe one of these hinges combined with a form of traver extender? Would be nice to keep the controls on the bar especially with the auto clutch. If you go jocky shift might as well use that as the clutch also with neutral at the top.

 

[wayne z]

Yeah, I'm gonna look closely at the scissor actuator,and gonna study a harley mousetrap. A larger dia idler will help some in lessening the amount of travel needed.
If I hafta go with a jockey shifter, I'll drop the auto clutch and use the handlever for an idler clutch.

 

[wayne z]

OK, made a little progress today . Got around to modifying and adapting the mount to the engine so I could bolt it down and try out the belt and pully..
Only took 3 trips to napa this week on the way to work to get the right sized belt. Doin the math got me that close LOL.

Good News! My math was wrong again, on idler travel, only takes 3" movement to get the full range. I think I can get a hand clutch lever to do that. Get one with a locking button and I can lock it in a lower gear if I am in slow traffic ect

 

[cannonball2]

This is looking like its going to work out great. If you can stay with the auto clutch, should make a great ride for high traffic situations. Also with the lower ratio you will have should pull smoothly from stop and acclerate pretty well. This is gonna be killer! BTW what color stain you gonna use on the primary drive-lol.

 

[KCvale]

Hey KC ,thanks. I never considered using a SBP jackshaft and derailer shift ect. I figured that stuff ain't up to the heavy duty power pulses of a 4 stroke and wouldn't be reliable. too many light weight moving parts. With a belt primary and secondary, there is slight slippage that eliminates the damage from torsonal viberation which is worse with a 4 stroke cuz they fire every other rev.

You are very welcome, I have a LOT of experience with the 2-stroke SBP jackshaft kits, I just haven't tried their 4-stroke one yet.

I haven't really found 'power pulsing' to be a main issue, that is trying to shift under power, but it is sure a concern with internal hub makers, especially NuVinci, but I won't go into that in your new tranny topic ;-}

NuVinci however recommends using a 'cush drive' with any piston powered motor on ANY type of drive.
For some reason they think a cent clutch, which 4-stroke kits have, helps that but I don't see how.

A 'cush drive' in essence is something pliable to even out the power pulses to as steady a power out curve as possible. Your belts and tensioner will do some of that.

I came up with this design for a 'cush' sprocket for the main sprocket on a Jackshaft for 2 or 4 stroke motors, I just haven't made it yet.

In short just a new primary JS sprocket with built in cush.

Like my crude Paintshop artwork? Heheheh ;-}

This is using actual available parts.

And this is how the power flows.

Anyway, you shouldn't have a problem with yours with the belts, they absorb a lost of shock.
If you want to look into Cush though I have a 3 page topic of what I working on here.
KC's Kruisers - Motorized Bike Forum - NuVinci shifter updated?

 

[wayne z]

OK, I got a little farther on the refinement of my primary drive case. Think I need to add a tab underneath for a primary idler in case I need it.
[/ATTACH]
All's fair game in a mock-up. Check out my battrey terminal pillow block jammed in there to take the belt pressure off the wood box LOL .

 

[cannonball2]

Thats gonna be sweet, but the engines backwards-lol. Seriously some really nice engineering.

 

[wayne z]

Thats gonna be sweet, but the engines backwards-lol. Seriously some really nice engineering.

LOL, Thanks. I have another idea about turning the engine around and keeping a variable belt secondary. Prolly be my next build if this one works out.

 

[curtisfox]

So nwhat do you think about useing a varie-drive out of a lawn tractor. They are on a pivit and when you move them forward and back the center web moves. When foward the belt is high on the outside and low on the inside. so when it is moved rearward it does just the opiset and giving you a double the change of your setup?
I can't waite to see how yours works out and I will be defently doing something like it. Love it ............Curt

 

[silverbear]

Yeah, I was thinking about a lawn tractor axle and drive set up and wondering if there is a way to come up with a rear axle set up on the cheap that works well. Always scrounging...
SB

 

[wayne z]

Yeah, That would be the MTD drive. I looked at those hard. I realised they sorta bulky harder to mount, had more range than I needed for a motorbike. I thought about it a while, and came up with this simpler and smaller design.

My ratios will be variable from around 15:1 low to about 10:1 using a 5" pully on the jackshaft.

I'm about 1/2 donewith machining the aluminum plates and spacers for the jackshaft case.
Been working out of town, making my time to work on it sporadic right now.

 

[curtisfox]

I think there are smaller versions of the MTD drive about the size of yours. I just can't waite to see how yours works out, along with the rest of the guys here.........Love it .........Curt

 

[wayne z]

Gettin a lil closer to havin it ready to run.
One of the hardest things about this build so far, is how to drill a hole in 1/4 aluminum that is about .001" smaller than the snap ring bearings that I want to use, for a good tight interference fit, with only a drill press.
Guess what! a 1 3/8" step drill from Harbor Freight does the job perfect
Now I have to set up a fly cutter and cut out a large dia hole in the outer plate to clear the auto clutch, and machine the spacers.

Wit a little luck, I might get a maiden ride tomorrow eve!

 

[silverbear]

Wayne,
If that runs half as well as it looks, you're good to go. I like it just sitting there. The way the engine fills up the frame, the belt drive and rear sheave... Oh yes!
SB

 

[BeaverRat]

Gettin a lil closer to havin it ready to run.
One of the hardest things about this build so far, is how to drill a hole in 1/4 aluminum that is about .001" smaller than the snap ring bearings that I want to use, for a good tight interference fit, with only a drill press.
Guess what! a 1 3/8" step drill from Harbor Freight does the job perfect
Now I have to set up a fly cutter and cut out a large dia hole in the outer plate to clear the auto clutch, and machine the spacers.

Wit a little luck, I might get a maiden ride tomorrow eve!
View attachment 43981

I'm getting anxious to see how this performs! Good job, if this works well, it will be one of my all time favorite builds on this site!

 

[vintagebiker]

Wayne,
I am looking forward to seeing how this vari speed system works out.
I admire people that build their own gadgets.
I have been kicking around a few different styles of drives, with simplicity, size and cost being a few of the most important factors, at least to me.
Maybe you have seen this already, but here is a cool website that has some basic layman engineering for a few different styles of vari speed drive pulley systems. Gives you an idea of horsepower requirements etc.
These are designed for electric motor drives but some of the info should carry over to any type belt drive.
Their set ups are not cheap but their design info is good food for thought.
Manufacturer of Variable Speed Pulleys, Adjustable Speed Pulleys and Variable Speed Belt Drives

 

[wayne z]

OK, gettin closer to a test ride. Got all the hard mechanical stuff done.
Just gotta finish up the idler control and throttle linkage , and fab the exhaust.

 

[cannonball2]

Stunningly nice fab work Wayne!