5:1 Transmission FWD Project

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lowracer

lowracer

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I really think this hobby of ours is wildly addicting & may become hazardous to our health...lol
My two MB's are running great & I hope I'm done tinkering with them for awhile. One is front V-Belt drive & the 2nd is rear Friction drive. I've never built a chain drive, so here we go.
I ended up with a 5:1 pocket bike transmission w/10T sprocket as a bonus for an engine I just bought (really didnt want the transmission, but got it).
I want to build a simple drivetrain with a freewheel so the engine can idle when I'm not on the gas (less clutch wear without engine braking & better fuel economy). I really like my front drive MB so this seemed like the simplest solution. I have an old fork lying around and spread the fork legs from 100mm to 120mm to fit a road wheel with screw-on 7 speed freewheel cluster. The 10T sprocket on the 5:1 transmission will fit a Track/Fixie chain which will also run the largest gear on the cluster. I may need to bust out one of my 3 boxed up pocket bike cag engines just to test this puppy out. I'll build a simple rack using the extra long 3/8 bolt-on axle & cantilever bosses as a 2nd mounting point.
Here is a pic of what I'm thinking...Has anyone built such a creature?
Please chime in.
-Lowracer-
 

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lowracer

lowracer

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wayne z,
Thanks!
I'm trying to do this project with absolutely no out of pocket expenses since I have all the bike parts, engine, transmission, scrap angle aluminum & steel, nuts & bolts & a house full of bikes...lol
If it all goes together well & has potential, I made a wish list of nice parts I'd like to buy to make it pro.
Surly makes the Pugsly fork & is 135mm wide & offset to fit a rear wheel w/cassette.
I'd ideally like a front disc brake as well so buying a nice MTB 26" disc rear wheel would also be nice & allow a fatter tire than the roadie wheel I got now.
But just to get the idea onto the road I'll do it cheapy style to see if it performs well & if I like chain drive.
I can already see gearing may be an issue since the large ring on my freewheel is only 28T (thought I had a 32T). Driven by the 10T & 5:1 transmission on a 27" OD wheel it may be a bit high on the gearing (8K rpm=45 mph). I'll either need a smaller OD wheel or less than 10T or 32T-34T on the freewheel...
I'll put it together anyway & see how it goes.
-Lowracer-
 
lowracer

lowracer

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bowljoman,
Cool scooter u built!
I found two other rear wheels on 2 of my bikes that will work better than the 700c in the previous pic. One is a 24" with megarange freewheel w/34T & the other is a 26" single speed conversion that I could cut off a 32T from an old cassette & use the many spacers to align the 32T exactly where I'll get a nice straight chain line. Just need to spread the forks another 15mm's for that one to fit...Its probably the best way to go since then I'll be able to use v-brakes to stop the front wheel too. I'm good without the ability to shift gears for both the motorized side of things & pedal side on all my bikes (not many hills here).
See pics
p.s. Are these 5:1 transmissions any good? I dont want that thing to be the weak link in this project since I need the reduction for it to work & I'm not a jackshaft kinda guy.
-Lowracer-
 

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Ludwig II

Ludwig II

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The little I know, I have from forums, but it should be better than the chain reduction boxes. Actually, to listen to the complaints, cutting your foot off with a hammer and chisel would be better than a chain box.
 
NEAT TIMES

NEAT TIMES

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lowracer

The 5:1 box is well built. Your final ratio with the 10 & 34 tooth will b 17:1 final ratio.

Your Cag motors like to turn rpm`s, a freewheel adapter with a 40 tooth would give you 20:1 final ratio. The 17:1 mite not let the Cag develope power. Knowing you, we will find out soon!! lol.

Ron
 
lowracer

lowracer

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Thanks Ron,
I have the v-belt drivetrain set at 15.6:1 & it is a good ratio for my weight & flat area for the Cags & Tanaka's. I have the 32cc & 40cc Tanaka's & really like them both but would love to find a new 47cc Tanaka somewhere? I found that spare MTB cassette I was looking for & sure enough its like brand new w/ 32T. I had to drill out one of the rivets to get it apart but that was easy. After cleaning it up I took a pic.
Now I know I'll go with the 26" MTB wheel converted to single speed with this 32T (its a Shimano XTR hub wheel too...sweet)
-Lowracer-
 

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B

bowljoman

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these 5-to-1's are awesome for longevity. Some of the other ones are not so good. The internal chain ones, and a couple others when not applied correctly.

On my setup, I have the 10-tooth tranny sprocket driving a 21-tooth input sprocket. The output and wheel sprocket are the same size, 20 teeth, and the rear wheel has a 12.5 inch outer diameter. So it breaks down to , in my 2nd gear(1 to 1) , 12.5 inches with a 21 tooth sprocket is acceptable with slight peddle assist, to start from a stand-still on flat ground. You have a 26 inch wheel, so you ideally would use the 42 tooth sprocket to match my ratio.
Depending on if you want speed or comfort, smaller rim for comfort. The 32 inch sprocket is similar to my third gear. Starting from a standstill is a clutch burner, and frame shaker if your mounts flex at all.

26 inch and 32-tooth should see 40 at Wide open throttle with a enough run-up. Probably max around 7000 to 8000 RPM if your engine aspirates at all. With a well worn 52CC scooter motor, I get 82.3% mile an hour per CC displacement with that tranny and the 3-speed nexus jackshaft.

So, I think If I were you, I'd find a 3-speed internal rim for the front, and couple it with the biggest sprocket you can.

My gearing with that tranny scaled up:
First is like a 55 tooth on a 26 inch wheel.
Second is like a 42 tooth on 26 inch.
third is like 28 tooth on a 26 inch.

These allow a 'NO pedaling to start' setup even on steep hills and it did 42.8 using a high mileage stock-form 52CC scooter/weedwacker motor.

Front wheel drive was the first option I considered in my last build, but I saved up the money to have the rear clip fabricated out of lucky circumstances.
 
MotorBicycleRacing

MotorBicycleRacing

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lowracer said:
p.s. Are these 5:1 transmissions any good? I dont want that thing to be the weak link in this project since I need the reduction for it to work & I'm not a jackshaft kinda guy.
-Lowracer-
Click to expand...
Hi Lowracer, have you seen any of the builds by TheScooterGuy?
he used the 5:1 gearbox with the motor bolted to the frame in front
of the rider.
Not an in frame mount but more of a frame wart sticking out by
your left knee!

Anyway he built a lot of bikes using the 5:1 gearbox using high
powered cag motors and never reported any problems with the gearboxes.
 
lowracer

lowracer

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MBR,
Oh yeah I forgot all about the scooter guy...
I know some members have his setup & are real happy with them.
'Wart'...lol
I could never bring myself to drilling a hole thru my bikes frame.
Thanks,
-lowracer-
 
M

mat_man

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from:
http://www.motoredbikes.com/showthread.php?37256-Dacs-5-1-gearbox-lubrication

"ALWAYS split the gearbox to check for lube. Most of the ones I've purchased were bone-dry.

The 5:1 gearbox has two plugs. One on the top to add oil, and the other is a drain plug on the bottom.

I've used oil, but it leaked thru the front seal.

So I pack a LOT of grease in the box. When new, it whined a LOT. I guess the gears are worn in, so not much tranny noise now.

Some tranny gearsets are bevel-cut; some are straight-cut.

When you split the case, you'll be SHOCKED how tiny the pinion gear is.

Aside from a leaking front oil seal and a loose clutch drum, the gearboxes take a LOT of punishment and keep on ticking. "
 
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bowljoman

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Totally +1 on the lube. I forgot!.

I seriously think I have over three thousand miles on this unit. its due for another top-off. I guess I got lucky on the seal. Ive seen the CVT packed with grease and then they leave out the oil seal that is hidden under the pulley.

Cant wait to see it in action!
 
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NEAT TIMES

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My diy shifter bike has the 5:1 and is mounted on the top bar and is awsun, fun to ride with the derailer gears and a titan 50cc 4 stroke. But you need 1/2 of a shift kit. Will try to down size some pics tomorrow, did not drill holes in my frame, it is my fav motorized bicycle.

Ron
 
lowracer

lowracer

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Since Hurricane Sandy is blowing up the east coast I got time to kill in the garage, I put more time today into building this chain fwd freewheel project together. I had a problem with my Dax friction drive unit. It sheared the clutch drum from the shaft at the weld & I contacted Dax about it. He was very helpful & told me to send it back for a warranty replacement. Excellent customer service from Dax...
Here are the pics of the setup & I took it for a maiden voyage around my neighborhood (roads are a little wet but not raining now) & it ran well. I will add a chain tensioner idler but for now I just pull up on the unit & tighten 2 bolts to tighten the chain.
I really like the way it freewheels when off the gas & no engine braking (causes excessive clutch wear & heat. On some engines snapping clutch springs).
-Lowracer-
 

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lowracer

lowracer

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One more pic.
Some of the details are:
- 26" MTB screw on freewheel rear wheel (LBS throwing it away & needed a good truing)
- Rigid fork spread to 120mm (by brute force)
- Litespeed Obed titanium MTB setup as single speed (I have owned since early 90's)
- Tanaka 32cc w/5:1 pocketbike geared transmission 10T
- 14-28T freewheel (using just the 28T)
- Fixie chain (swiped it from my fixie roadbike 1/2" x 1/8")
I got the engine as close to the headtube as possible (above the axle centerline) for best handling.
I didnt buy anything new to build this so out of pocket has been zero. Only problem is now I have a full suspension downhill MTB without an engine...lol
-Lowracer-
 

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lowracer

lowracer

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Did some math on the gearing & with this little 32cc Tanaka, I'll be better off putting a 14-34T megarange freewheel on there & use the 34T.
28T @ 8000 rpm = 44 mph
34T @ 8000 rpm = 36 mph
I dont think this engine is strong enough to pull 44 mph & on this lighweight rigid bike, I dont want to go 44 mph!
I got one of them Shimano Megarange freewheels laying around here somewhere & will install it tomorrow along with a rear slick tire then take one WOT spin on the 28T for scientific research...lol
I also had an idea to better mount the drive channel with more support which I'll also do tomorrow.
How much fluid (oil) do you run in these 5:1 pocket bike transmissions?
I added just a little 10W30 motor oil since it was dry, but not sure what is recommended or preferred? There is very little info on the internet about caring for these 5:1's
Thanks
-Lowracer-
 

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BigBlue

BigBlue

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lowracer said:
How much fluid (oil) do you run in these 5:1 pocket bike transmissions?
I added just a little 10W30 motor oil since it was dry, but not sure what is recommended or preferred? There is very little info on the internet about caring for these 5:1's
Click to expand...
Staton uses grease for his gearboxes and I don't know why you couldn't for that 5:1 box.

Here's Saton's instructions for his gearbox:

If you use Mobil Grease XHP 220 Series (thin blue grease) only use about 6 oz.
These are designed for Cam 2 Ultra 580 EP #1 Extreme Performance Synthetic Grease.

Good Luck,

Chris
AKA: BigBlue
 
16v4nrbrgr

16v4nrbrgr

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I think you fill them up until it drips from a horizontal filler so that its about halfway full. On pocketbike planet they just say to put whatever in, but I think gear oil would work best, the stuffs stinky though.

I like your FWD builds, they're way outta the box and unarguably effective.
 
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