In frame Predator fricton drive build

GoldenMotor.com

wayne z

Active Member
Dec 5, 2010
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I've been thinking about this a while, and I mocked up the prototype today.
This would be an easy way to turn these slanted motors around with the cyl facing foreward.
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I think that by using a 3" dia roller the efficency would be way better than the small dia rollers that are common. And the reliability and simplicity of a large roller FD would be great.
The first try will prolly be with the roller in a fixed positon.
I want to eventualy try a hinged one with the right geometry to make it swing in and "self engage" when a clutch lever is released, to get max tracton for bump starting. If this works, I can remove the pull starter and tin for a real cool look, and the total width with drive pulley will be 8.25" instead of a not too bad 10" with starter.
 

cannonball2

Well-Known Member
Oct 28, 2010
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Colonial Coast USA.
Thats cool Wayne! I have been thinking along those lines my self. The first whizzers were friction drive with a belt involved, with the engine inframe. That 3" roller will haul A$$ if you can pull 4800 from the engine- talking 40+ mph! You are right about the reliability of the larger FDs. I ride mine constantly with no issues. Might want to consider using an auto clutch, kills a roll start and the tin removal, but makes a delightful bike even my wife enjoys riding, makes traffic almost tolerable. Any way will be watching with interest!
 

deacon

minor bike philosopher
Jan 15, 2008
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I definitely like the in frame thinking. Actually they make lots of bike chain sprockets for those engines. You could put one of those on it and use the center from a caster wheel as the drive. just a thought. My mind is racing.
 

wayne z

Active Member
Dec 5, 2010
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Thanks guys, for the kudos.

I am going with a fixed roller and a v-belt auto clutch , and a 3.5 inch roller for max contact . I can change the rollershaft driven pully to easily change drive ratio to what works for me.

Hey CB, can you recomend a vendor for the MaxTorque clutch?

What is the width of the clutch that you are using?
 

cannonball2

Well-Known Member
Oct 28, 2010
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I was in the lawn equipment business for years,and now buy through a friends business who gives me a 25% discount on whatever I buy. The clutches are pricy list wise in the 50s maybe, funny I never even look at the invoice. There is to my knowledge only one Maxtorque for pulley application with a 5/8 shaft. It has a 3.2" pulley. I have tried, using my variable pulley ratios from 4"-3" on the pulley, its really cool to be able to change roller speed. My latest build is going to have roller overdrive, engine 4800, roller 5119 with a 2.25" roller for a 35mph to speed, interested to see how well it will pull it. I looked at trailer rollers, almost bought a polyurethane, they were too big/tall for a rack type mount, should be perfect for the inframe though. Ebay is a good source for flange/pillow bearings, have bought several sets in the 8$ ea range. This is gonna be cool!
 

wayne z

Active Member
Dec 5, 2010
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Dan, I don't think there's a noticable difference in the physical size or weight. This thing is tiny and light. 18.5 lbs. stripped as in the photo, 9" tall,12" long and 9" wide excluding pto shaft.

Cannonball, who did you buy the Maxtorque clutch from? Thanks for the E-bay tip
 

cannonball2

Well-Known Member
Oct 28, 2010
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Wayne, I pay about $46 for the clutch from my friend. Goggle them, I just found several in the $45-46 range. You could easily build your jackshaft using flange bearings and allow the bearing to pivot the adjust roller tension using a cam lock or similar. The biggest draw back to the trailer roller is it is very wide unless you are cutting it down.
 

wayne z

Active Member
Dec 5, 2010
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Thanks CB. Not gonna use the trailer roller, too small dia. it's in the pic just to show the location and idea.

Gonna start with a 3.5" wood roller for testing. If this concept works, I want to try 2 or 3 stacked bench grinder wheels
 

Dan

Staff
May 25, 2008
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Moosylvania
Dan, I don't think there's a noticable difference in the physical size or weight. This thing is tiny and light. 18.5 lbs. stripped as in the photo, 9" tall,12" long and 9" wide excluding pto shaft.

Cannonball, who did you buy the Maxtorque clutch from? Thanks for the E-bay tip
That is awesome, good news Wayne, thank you.
 

cannonball2

Well-Known Member
Oct 28, 2010
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Hey wayne, heres a pic of a solid plastic deck wheel I bought for a potential roller. These things are tough as nails. Even with its current slick finish it had good friction with a bike tire. I figured to slot it on my band saw, the rough it with 40 grit across. It is 3", with a 1/2" hole, easily enlarged to 5/8" for a jackshaft, exactly the width of a cruiser tire. Cost around 4 bucks as I remember. Was too big for my project. Something to think about.
 

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lowracer

New Member
Oct 17, 2008
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Wayne z,
I would email Jim @ Max-torque before buying the pulley clutch. I bought one & after a few emails w/Jim, I sent it to him for a major revamp. For $49 more he rebuilt the clutch with a 2.8 billet v-pulley, precision sealed cartridge bearing (no more oil-lite bushing) & better shoes & springs. I would have saved a few bucks just ordering the clutch w/the mods directly from Jim. The clutch is way better now & I dont need to constantly lube it.
-Lowracer-
 

rustycase

Gutter Rider
May 26, 2011
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Left coast
GREAT post!

This could very well be the silver bullet for the 'reverse running motor' and those required tiny diameter rollers for the friction drives!

There are truly great possibilities with this setup !

Best
rc
 

wayne z

Active Member
Dec 5, 2010
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CB, thanks for the info on the 3" roller, hafta get one or more of those to experiment with.

LR, thanks for the tip about the clutch with better bearings ect. I thought something like that was available, now I know a source. I agree with it is cheaper to spend a little more up front for stuff that will give better and longer service .
 

wayne z

Active Member
Dec 5, 2010
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Ok, I got a chance to work on my Predator fricton drive today.
I kinda designed it around what I had laying around,and a little scrounging.

I decided to put the clutch on the jackshaft, to keep the motor as narrow as possible, and to experiment with using the clutch drum as the fricton roller.
Ultimatly, I want to turn and knurl a 2" wide sleeve from 3.5 od pipe to press fit over the clutch drum.

Also wanted to do this project without welding anything,or drilling the bike frame. Notice that the aluminum plate in there is notched tight against the seat tube, to stop lateral movement in that end. Bolt thru the fender stay takes care of the other end.

I pedaled it around some today. Not much drag at all from the large roller. Felt about like the chain drag from a HT .
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wayne z

Active Member
Dec 5, 2010
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Got it running today,just before dark. Had to cancel the testride cuz It had just rained. It worked real good while in my basement, but when I hit the wet muddy driveway it quit pulling due to the narrow, slick clutch drum contact roller. Def will need the knurled sleeve in the future.

The Preditor engine starts and runs real good. Snappy throttle response, can't wait to load it and see what it does.

I want to try it out some before I commit to building a decent exhaust system

Won't be able to get back to it until Friday.
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