Reverse-neutral?

Clutches, Chain & Belt Drives

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TimppaX
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Reverse-neutral?

Post by TimppaX » Sun Jul 18, 2010 3:47 pm

Been on busy at other parts of life, but building bike. :x

Anyone know is there way to add reverse & neutral to cvt?
that should do it

IgorVigor
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Re: Reverse-neutral?

Post by IgorVigor » Sun Jul 18, 2010 4:09 pm

from what I know, you cant really have a neutral or reverse on a CVT itself.

what you have is a reversing box, which sometimes have a neutral...

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Re: Reverse-neutral?

Post by albertaphil » Sun Jul 18, 2010 9:17 pm

If your CVT jackshaft does not go into a gearbox with a neutral and reverse, what you can do is add a disengagable drive to your jackshaft to turn the shaft in reverse when your engine is at idle.

Picture it...your CVT consists of the primary pulley on the end of the crankshaft which doesn't engage the belt when the engine is at idle. Above idle speed the primary pulley grips the belt and moves it, which then spins the secondary pulley. The secondary pulley turns the jackshaft which has a sprocket on it to turn the chain to your rear wheel. It really wouldn't be very hard to mount a little gear onto your jackshaft in addition to the chain sprocket. You could then drive the gear with a starter motor from a small engine that you could activate with a push button on your handlebars.

Alternatively (and this wouldn't be quite as sexy), you could extend your crankshaft on the flywheel side and add a v-belt pulley. Then you would need a jackshaft that was long enough to extend out as far as your new flywheel-side belt pulley. Add another belt pulley onto your jackshaft and string a v-belt between the two with a twist in it to reverse the direction of rotation. The hangup here is that you would need a lever setup or something to loosen the belt when you don't need reverse. Or you would need some sort of little clutch at one of the belt pulleys.

These aren't really well-formed ideas, but they seem like they would be workable for someone who liked to tinker.

Thoughts, anyone?

Cheers,
Phil

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coachgeo
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Re: Reverse-neutral?

Post by coachgeo » Sun Jul 18, 2010 10:18 pm

Electric reverse as you mentioned was my thought too.

For neutral.... was thinking of a throttle stop, preferably on the hand throttle that you can thumb click and lock the throttle so it can NOT be accelerated. Not just for reversing reasons... but so a dimwit can't bump your throttle thinking he's going to listen to the engine rev., and make the bike take off.

Had not thought about the opposite side crankshaft belt idea (fan side of the engine you might say), but that would require also a disconnect of CVT belt drive somehow since you would be accelerating the engine to get it rolling back.

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Re: Reverse-neutral?

Post by TimppaX » Mon Jul 19, 2010 5:25 pm

I´ve seen&used snowmobiles with reverse-neutral-drive lever, sometimes 1 & 2 different forward "gears".

Anyone ever isntalled such a system to shaftdriven bike?

Other way around is to use customised Aixam/Microcar/.. transmission. But space is the issue, they are too bulky for my build. Unless it evolvs to a trike.
that should do it

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Re: Reverse-neutral?

Post by coachgeo » Mon Jul 19, 2010 6:08 pm

crazy idea? Put reverse on the front tire. Electric with either chain drive or wheel that you push against the tire type drive.

hmmm...... with that in mind a push against the tire type might can be put in back too if there is room.

If your a dual sport bike.... extra electric motor drive on front tire, if you can spin motor in both fwd and rev.... might help you thru some nasty stuff like mud or sand hmmmmmmmm

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Re: Reverse-neutral?

Post by coachgeo » Mon Jul 19, 2010 6:12 pm

idea above gave me another reverse idea.

Electric motor with chain a second sprocket on either side of rear tire.

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Re: Reverse-neutral?

Post by IgorVigor » Mon Jul 19, 2010 6:20 pm

coachgeo wrote:idea above gave me another reverse idea.

Electric motor with chain a second sprocket on either side of rear tire.
If you chose the correct motor, you could double it up as a alternator :P

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Re: Reverse-neutral?

Post by coachgeo » Mon Jul 19, 2010 7:06 pm

IgorVigor wrote:
coachgeo wrote:idea above gave me another reverse idea.

Electric motor with chain a second sprocket on either side of rear tire.
If you chose the correct motor, you could double it up as a alternator :P
ahhhhhh.... good point.

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Re: Reverse-neutral?

Post by roodesign » Fri Sep 24, 2010 3:11 am

Check this unit out...I ordered one of these with the appropriate shaft for a Comet 94c just about have it installed in the ROOPOD ( http://www.roopod.com ) I will have pictures of it on my site soon! Pricey but looks very first rate...




http://www.novaracing.co.uk/reversing-g ... ng-kit.htm
Attachments
CVT Reverse Gearbox 003.jpg
CVT Reverse Gearbox 002.jpg
CVT Reverse Gearbox 001.jpg
roo trimble
http://www.roopod.com
Shutesbury, MA USA

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coachgeo
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Re: Reverse-neutral?

Post by coachgeo » Fri Sep 24, 2010 4:34 am

Wow very interesting. Look forward to your report on it.

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Re: Reverse-neutral?

Post by roodesign » Sat Nov 06, 2010 4:23 am

The roopod is far from done, but is now street legal..check out more on the blog: http://www.roopod.com that's me and the misses' when we got the 'pod inspected...now have 170 miles on it! nova racing reverse gearbox is doing great shifts like a dream!
Attachments
IMG_2246.jpg
LEGAL!
IMG_2219.jpg
out on the road!
IMG_2255.jpg
My Wife and Me
roo trimble
http://www.roopod.com
Shutesbury, MA USA

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