The Huffy Puch project

[professor]

This is bike 2, after realizing bike one is akin to a buckboard (even with the suspended front end, sus. seat post and cruiser seat) at my typical 20 mph cruise speed, I decided full suspension and some more hp would be nice.

The Huffy frame is stretched a bit with a full suspension triangle grafted in. Wheelbase 53". Using Puch wheels and front end.
Black HF 6.5 engine.
Idler clutch with HT lever & belt drive to a bike rear hub (acting as a jackshaft) to chain to the back wheel.

Initally I wanted to use a derailer on the drive side but that did not work out at the time. The chain needs a lot of tension on it to stay on. It may yet work by limiting the selection to 2 gear speeds. My tensioner is a lot stronger now.
Anyway, I have been running single speed and the engine has so much torque (12 ft. pounds and 9+ hp with the free breathing intake / exhaust and re-jetting).
That take off is no problem, slipping the clutch a bit. Gearing is 7.5 to one.

top speed on the tweaked governor is 35mph.

I posted how this engine is a vibrator. I actually bought a go-kart clone engine to replace it and the clone vibed just as bad. I went with isolators below the engine and rubber snubbers on top to hold the engine and this totally solved the buzzing. Still shakes at idle like before, but gets silky smooth at rpm. It's like a different engine.

I don't know how the bike chain will hold up over time. I pounded on the 10 speed chain that I began with for acceleration and speed tests, no problem, but, it came off and wrapped up a few times during the derailer testing.

That chain came apart going uphill on the way home Sunday.
Switched to a cruiser chain that was unmolested.
I would love a full belt drive but will wait to see how the better chain hangs in there. The belt slipps a bit on WOT but is no problem.

This thing rides like a dream! It is heavy @ 130# , seems like a small motorcycle. Very stable. Brakes could be better, using a dual brake lever, the moped brakes disappoint me a little. Bike one with calipers stops a lot stronger.
Very quiet, with the long exhaust system and a drilled- out Puch muffler, it has a subdued cycle sound.
I am pedaled- out at 10 mph, so I don't get much exercise on bike 2, but I sure like the power and the ride. Fuel milage seems great. The engine is loafing almost all the time.

I succomed to practicality by putting a basket on the back rack.

The center pic is a sample isolator. These things are the cat's meow.

 

[silverbear]

Pretty cool build, Professor!
SB

 

[charliechaindrive]

nice bike doc hahaha

 

[silverbear]

Do you have close up pictures of the drive line? And you are using a 3 speed Sturmey Archer 1960's hub as a transmission separate from the rear wheel. In other words the transmission is part of the jack shaft assembly. I'd really like to see that in more detail You are the only one I know of who has successfully used one of the old 3 speed hubs... congratulations! Every time I look at one on an old English bike I keep thinking how it is too bad they don't hold up under motor power. Yet yours does and you have a whole lot of motor. I wonder if the belt driven parts of your drive line makes the difference.

Where did you get the isolators?

This build has not gotten the attention it deserves.

Well done, Professor!
SB

 

[professor]

SB- I just noticed this post after detailing some pics on the other thread.
I think the isolators cam from McMaster Carr. On a smaller engine I doubt they would be needed, my 79cc HF doesn't need them.
I do not understand why a 3 speed hub would not hold up. A 220 pound guy pumping down on the pedals has to be doing at least 100 to 150 foot lbs to the hub. This is within range of say, 3 ft#s of tq.(small engine) multiplied by the final drive ratio.

 

[silverbear]

If you say so,,, ha. I think I must have skipped school that day.

I know that one failure was in conjunction with a shift kit. Caduceus used one (maybe it was an old Shimano) as part of a jack shaft for his recent trike build and it failed even though he was being gentle with it. It seems to me there have been others a good while ago. At any rate, I'm glad to see that yours is working. You mentioned this as the second one. What about the first?
SB

 

[BigBlue]

For those that are interested, Sheldon Brown has a couple good articles on 3 speed hubs:

1. Shimano: http://sheldonbrown.com/shimano333.html - has some more info. on product development and quality cycles, along with some more info. on Sturmey-Archer.

2. Sturmey-Archer: http://sheldonbrown.com/sturmey-archer.html

Good Reading,

Chris
AKA: BigBlue

 

[silverbear]

Blue,
Thanks for the links. I had no idea there were so many SA models made and the discussion about quality control through the years explains perhaps why some hubs fail more easily than others.
SB

 

[professor]

SB, my first one uses a HF79 with the same basic drive system idea, but using number 25 chain after the initial belt and then bike chain to the rear wheel (like bike 2).
I do not like the hard ride of no suspension in the rear, even though it has a suspension seat post.
Having the Puch parts laying there (bought it for the registration- to make bike one legal), then I thought- why not make another bike using the moped wheels and front end + make it full suspension. = Huge contrast. Buckboard vs model A.

The odd thing is the gas milage between the two bikes is the same- around 120 mpg.
The little motor is much smoother and is wound out at a bit over 30, but the big HF starts with one pull and I love the power. If I ever want to use bike one- I swap the plate over to it, but that hasn't happened in a while.
Bike one- covert style-

 

[silverbear]

Nice!
That was a good idea using the Puch for the registration. So now you have a plate. Did you also have to put registration numbers on the frame? Seems silly to have to in a way as it already has the Puch wheels and front end. Best to stay on the safe side with the powers that be and they have gotten a bit of money through your license plate which makes you an A1 citizen. Ha. Nice to have a back up bike, too, just in case something goes wrong with your primary ride.
SB

 

[professor]

Kinda long story- was at a high end bike shop where an electric bike was on display and the guys there told me E-bikes were legal in NY. News to me.
Not wanting to deal with batteries, I devised a gas/electric bike
.
Bike One was this set up. A HF driving a Ford alternator/ juicing a scooter motor/ battery driving the rear wheels.

Found out the bike guys were wrong (or lying). So I bought a basket Puch with a good reg. made a tag with the numbers steel stamped on it and blended it into the frame.
Hooked up lights. Got the plate. No state inspection on this low level rig (no hoop to jump thru there).

In use, the HF was working extrememly hard pushing my 140 pounds around.
20 mph was top speed.
Finally I decided to ditch all the electric drive stuff but still use the HF.

Huge difference, later I found out alternators are only about 50% efficient and the stack up of inefficiency was killing my rig.

Then I went from straight drive to the SA hub and again- huge difference is usableness and acceleration.

Both bikes have the pedal system intact.
On bike One I can pedal with the motor to about 20 mph using the derailer shift. Bike Two I can pedal up to 10 mph. It is nice being able to pedal home in the event of a mechanical bug. Tough (130# bike) but nice.

I don't remember if I ever posted the video of the gas electric, but here it is-
http://www.youtube.com/watch?v=k_VooEJdgoE