New vari speed tranny build

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wayne z

wayne z

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Dec 5, 2010
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That's a real good question. I did give this some consideration, and decided to gamble and see.

This pully is designed to keep a constant working tension and lower maintenance intervals on belts in hard to reach air handling equipment. Sometimes it is used to adjust the speed of the blower by adjusting the motor distance.

I decided that if it is supposed to keep the belt tight enough to do work, then it's a fair gamble to buy one and try it.

Hopefully, 3 hp isn't enough to overpower the spring pressure of the sheave, which is kinda stiff, With 8 fingers and both hands, it is slightly easier to operate for me than a HT clutch case lever with 4 fingers.
Only a test drive will tell for sure.

I luv experimenting :~)
 
wayne z

wayne z

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Hey SB, so far, I've got about 300 bux in all the drive train parts except belts. That don't count the cent clutch I already had.
Engine $99, engine mount $30, 12x24 x1/4 aluminum plate $40, vari sheave $65, Wizzer sheave $65 bearings $15, jackshaft $24. These prices include shipping from seperate vendors.
Curtis, the catalog # for this pully with 3/4 bore: 6568k13
 
silverbear

silverbear

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Jul 9, 2009
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And that is a Comet clutch that you have? What would one of those go for roughly?
I can see that I could cut the expense for myself by making my own engine mount for about $10.00 using scrap aluminum plate, angle, hockey pucks and U bolts. I think I have aluminum plate that size(12x24) and a sheave could be made from a bicycle wheel. Money saved on things like that can go into better wheels, brakes, etc. I sure hope this works the way you want it to. Thanks again for sharing, Wayne!
SB
 
wayne z

wayne z

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Hey SB, The Comet clutches are kinda pricey new.
Comet SCDP 350 Series Double Pulley Clutch. | MFG Supply

I already had a couple laying around. They were standard on some Yazoo pushmowers. I like them cuz they have a bushing twice as long as the single pully Maxtorque, and give less trouble with clutch bell chattering at low speeds. This is a slipper type clutch that don't lock up early.

You can buy a Maxtorque roller bearing clutch for about 80 bux or the standard bushing model for abt 50 bux.

The maxtorque has a larger pully, so you would need a larger jack pully to keep ratios the same.
If you use a jockey shifter, you can build an idler clutch real cheap, and I perfer them over the cent clutch.
 
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wayne z

wayne z

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Ok, I stripped down the Huffy and started the mock-up last night.
I cold set and adjusted the spokes and trued the wheels. thet came out tight and straight. They are steel wheels and large dia spokes, I'm gonna give them a try. Really like to save my new wheels for a better bike. IMAG0146.jpg

Now I need to start figuring out the jackshaft plate for the motor next.
 
cannonball2

cannonball2

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Oct 28, 2010
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Looks good Wayne. We have discussed this before, the MTD pulley. This should work also with a dual belt drive. Would require two spring loaded idlers which are a good thing any way on an all belt drive bike. This thing should have a big ratio range as both pulleys change size. In low the primary is very large and the secondary is very small. In high the primary is very small and the secondary very large. Probably has more range than the bike needs. It runs on a fixed shaft on Torrington bearings, doesnt really even need a formal jackshaft. The mounting bolt as I remember is hardened and has a Zerk in the top. These things run for years in mowers totally negelected. I may look into putting one on my dual belt Cranny after I finish my current build. Will be almost a bolt on except for the linkage. I imagine it would have to be a gated hand shift of sorts.I think I can lay hands on in the $60 range if they are still in the aftermarket.917-0800A NEW *OEM* MTD VARIABLE SPEED PULLEY 717-0800,717-0800A *OEM* | eBay
 
wayne z

wayne z

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Hey CB, Merry Christmas. Yes, we discussed the MTD pully and the constant tension pullies before. That's what got me thinking, and inspired to try the single vari-pully setup.
In fact, most of my bike projects lately have been inspired by your experiments and discussions. I would never considered belt powered fricton drive on my last build if I hadn't seen where you tried it. Thanks :~)
 
C

curtisfox

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Dec 29, 2008
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cannonball2 said:
Looks good Wayne. We have discussed this before, the MTD pulley. This should work also with a dual belt drive. Would require two spring loaded idlers which are a good thing any way on an all belt drive bike. This thing should have a big ratio range as both pulleys change size. In low the primary is very large and the secondary is very small. In high the primary is very small and the secondary very large. Probably has more range than the bike needs. It runs on a fixed shaft on Torrington bearings, doesnt really even need a formal jackshaft. The mounting bolt as I remember is hardened and has a Zerk in the top. These things run for years in mowers totally negelected. I may look into putting one on my dual belt Cranny after I finish my current build. Will be almost a bolt on except for the linkage. I imagine it would have to be a gated hand shift of sorts.I think I can lay hands on in the $60 range if they are still in the aftermarket.917-0800A NEW *OEM* MTD VARIABLE SPEED PULLEY 717-0800,717-0800A *OEM* | eBay
Click to expand...
I have some of these and thought they were to big around about 5" in diamiter. If a guy could find a small say 3" it would be a lot better........Curt
 
cannonball2

cannonball2

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The current pulley I am running is 5" in order to get the desired 11:1 ratio I am running, so should fit in the same spot easily, and it basically not much wider. I imagine the full range of travel would not have to be used as it would be quite broad simplifying the shifter arrangement. The lawn tractors had as many as 7speeds/positions over the travel. Heck might could use one of the shift gates from the tractor.
 
rustycase

rustycase

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May 26, 2011
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Roger that...

lol
I NEVER could adjust mine quite right.
My bud had one on his, it was like passing yer finger thru butter... worked like magic.
and all he did was make adjustments precisely by the book.
lol I tried, and tried... never could get it as nice as his.

working out the geometry and getting a suitable spring would be a task.
fun stuff!
rc
 
KCvale

KCvale

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Feb 28, 2010
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wayne z said:
Ok, I stripped down the Huffy and started the mock-up last night.
I cold set and adjusted the spokes and trued the wheels. they came out tight and straight
Click to expand...
Outstanding!
This is certainly one heck of a drive train you have going.



(I took the liberty of taking your pic and making it a little easier to see)

I was looking at the stats for the Harbor Freight 99cc and the HS/Honda 49/50cc motors today and seen a stark difference.

The HF 99cc Predator has a max RPM of 3600RPM with 3.5 Ft/lb max torque at just 2500RPM.
The Honda 50cc has a max RPM of 7000RPM with 1.9 Ft/lb max torque at 4500 RPM.

Are you gearing towards the dramatically lower Predator motor RPM power range?
 
cannonball2

cannonball2

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KC, the Preddy turns ungoverned upwards of 6000 rpm according to the latest work Quenton has done with it. He has been getting speeds over 50mph with the EZM. With a variable ratio like Waynes I would exlect at least the same.
 
wayne z

wayne z

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Hey KC, yes, I am gearing for 5000 rpm. That is where my current 99cc seems to like to top out. Shooting for 15:1 in low and 9.75:1 in high.

Got a little farther on the build last night. Had to make a little jack to spread the chainstays for sheave clearence.

Then I started with plywood plates for the mock up. When I get the geometry figured out they will be templates for the aluminum plate housing. Also have go grind on the engine mount some for belt clearance.
IMAG0162.jpg

IMAG0157.jpg

IMAG0151.jpg
 
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KCvale

KCvale

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Feb 28, 2010
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cannonball2 said:
KC, the Preddy turns ungoverned upwards of 6000 rpm according to the latest work Quenton has done with it.
Click to expand...
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 ;-}
 
C

curtisfox

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The part # is posted in earlier post.

That jack looks like a miniture spring spreder used to spred a old car spring. Simple tools love the homemade. Did you bend the cranks?

Thanks for showing lots of closeup pictures and detail................Curt
 
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