3 speed jack shaft

Jeebus, I've never seen the guts of a 3 speed hub before and now I know why!

That thing has more bits in it than the chinagirls do lol
 
don't know the exact ratios of the hub but 1st is an under drive, 2nd is a 1-1 ratio and 3rd is an over drive, i fired it up on the stand today and ran it through the gears, it's pretty freakin cool to watch it change speeds. going to do a road test soon, went to put my new tires on and they wouldn't fit my rims, using 26x2.125 tires but these old columbia rims take a tire for a V-7 rim what ever that is, going to the bike shop on monday to find out and get a set.
the whole point of the hub was that the 3-1 reduction on the gear box's isn't enough for a nice riding bike, i'm using the honda GX35 motor, it's a kick as* motor, fires up on first pull and hardley makes a sound. the chains turning make more noise than the engine, no vibration either. i think everyone is going to like this bike, it's getting a streached tank and full skirted indian style finders, gun blued frame and silver paint, with springer front end and drum brake dyno hub.
 
Finally........I was wondering what that object was at the end of the hub shaft. I understand completely now. Is that the same 3 speed type hub from 3 speed bikes in the 70s or a completely different design being more heavy duty? .......TY ALL FOR YOUR INPUT.
 
it's a non coaster brake hub from a 70's bike. has the push rod shift instead of the little chain. i took the casette hub off of a 10 speed wheel, milled it to fit over the left end of the 3 speed hub and welded it on. now i can swap the left side sprocket on the hub with any of the gears from the 10 speed to change ratios if i want to get more or less reduction.
 
...and my earlier tooth numbers as a comparison was an estimate. I may run the exact numbers for reduction at some point as I have some 3 speed hubs and I am thinking of using one.
 
hmm i wonder i it is possible to remove or lock the freewheel and brake arrangement on those old 3 speed. if possible then we could use them with the left side chaindrive of the ht engines, just by turning the wheel arround.

could this be possible or are this just a pipe dream??
 
BarelyAWake said:
Jeebus, I've never seen the guts of a 3 speed hub before and now I know why!

That thing has more bits in it than the chinagirls do lol
Click to expand...

Taking apart a 3 speed hub is like taking the mainspring out of a clock, more stuff comes out then could ever possibly go back in. rotfl
 
as far as ive read on ther interweb tonight i depends on the type. the sturmay archer type will almost explode in your face with small springs and cogs everywhere when you pull it out of the hub, while the sachs torpedo type you can remove as a comple unit. Maybe i should try to steal an old back wheel and hub from the junkyard
 
this one is a shimano, i took it apart, not to complex, my first thought was to lock out the rachet but there was no way to do it and still have it shift, you could do it but it would be forever locked in one gear. got my tires today, there called S-7 when there for the old odd ball rims. will be doing a road test wendsday.
 
I used to use the model 3S Shimano on a shifter bike. A LBS had 500 of them he got at auction. He sold them to me for $25 each.

I blew 4 or 5 of them before giving up on them. I found them to be quite fragile, especially in 1st gear. I missed shift and they explode. You end up with a 2 speed sometimes. They are very sensitive to input. A harsh or rough drive will kill it. Sometimes they got hung up in first, you shift to 2nd, apply power, still in 1st! Muck around with the shifter apply power again then blammo, they wont any accept power while shifting and If you make a mistake then Ka-Boom. The old 3 speed Sturmeys are worse.

And I was being very careful ofter the 2nd hub grenaded.

Be careful and your mileage may vary but I would have plenty of spares on hand.

The units I used were new and never used. (NOS)

Some of them had a "false neutral" between gears, If you accidentally apply power when its in "neutral" and when it "catches" ... you get to hear the tiny gears and pawls self destructing.

Setting up the shifter mechanism is critical for smooth operation, any cable stretch or miss-aglignment will be cause for a Ka-Boom.

They also like to spin the axle, so stake it down good.
 
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went for a test run today. everything works but i need more reduction, going to have to swap some gears, it rides super nice, no vibration at all, even with the motor not being able to rev out i was still able to go as fat as my 2 stroke bikes. once i get the gears right this thing is going to fly.
 
Cam Lifter - I was wondering what engine are you using? Sorry if it has been asked. That gear box lends itself to your application. Keep us posted on the duribility of your box. It would be nice to find some of the old English boxes. They were small and look cool also. Good looking work. Have fun, Dave
 
the engine is the honda GX35, not a knock off, 35cc 1.3 hp. i really like this engine, it dosen't have a flat bottom, it's more rounded and lends itself to being hung from the frame instead of plate mounting it. it's not as wide and weighs less than the honda 50. theres a night and day difference between this bike and my other 2 stroke china bikes, so much smoother it's like no MB i've ridden before. this is the bike i'll enter in the biker build off.
 
I was wondering what gear you had it in for the road tests?

I gather you don't have a shifter yet. So I will give you some of my experience again.

The handlebar shifter on these shimanos is indexed, you set the shifter's position in 2nd on the shifter then adjust the barrel screw on the bell crank to line up the two index marks.

Then first is pulling out and third is pushing in. The stock late model shifters run a solid cable as to allow for positive push and pull. This corrected a known shifting issue. Later bell cranks also had a protected lever and better setup method using a set screw and template included the box

First is not all the way out and likewise third is neither all the way in.

Some of the problems I had were because of this critical setup being lost with vibration, cable stretch or the barrel screw coming loose. And the imprecise method of setup with the early bell crank that you have. Is the bell crank screwed on 4 or 5 turns?, are any parts bent? , is the rod the stock length ect.


Also I would strongly recommend using only Shimano parts for the shifter, Unless you know the travel required between gears.

I have 2 shifters here, one early style that uses flexible cable and the improved later style along with the correct solid cable and better bell crank if you are interested.

Also I hope you installed the special anti-torque washer or that sucker will spin its axle.

And good luck, you will be spinning this part way above its design with a pulsing input, that's why they like to blow up in first gear. 2nd might get you home though.

If you already knew all of this then disregard.
 
for the test i just reached down and held the shifter with my hand and ran it through the gears, real clumsy riding with one hand bent over holding the shifter but now i know it works and has the right ratios on all the sprockets. for the shifter i'm building it to look like a suicide shift from the 20's, will be all rods and heim joints with the shifter sticking up by the tank. this is my first 4 stroke and i am really impressed with the smoothness of the ride, it has a little less power than the 2 strokes but a higher top speed. what hubs are the people doing jack shafts and free wheels to there 3 speeds using, i don't here of them saying there having a bunch of problems with it.
another thing, the bike pedals just like theres no motor, no drag at all like on the 2 stroke kits when you pull the clutch in.
 
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