jack shaft on a cruiser

Shadeslay

Shadeslay

New Member
Well I just got a jack shaft and have run into my first problem. Installing the cranks, I took my one piece off the bike, but I can't seem too take the parts attached too the bicycle frame to add in the new bottom bracket.

Do they thread on, should I just beat the carp out them with a hammer, blow torch and dynamite?
 

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If you think about it, those bearings get a huge workout with the jackshaft. That thing is spinning 100 % of the time now.
Others may know better, but I thought it was very important to drill a small hole into the bottom of the bracket and I wound a grease nipple into it. It took three minutes and now I can keep grease on the bearings. It's easy if it's apart.
 
Wow that's a good idea, something I'll likely do sooner or later. I already have that part done and really want to test this bad boy out, so it's likely too be later. :D
 
toytime said:
If you think about it, those bearings get a huge workout with the jackshaft. That thing is spinning 100 % of the time now.
Others may know better, but I thought it was very important to drill a small hole into the bottom of the bracket and I wound a grease nipple into it. It took three minutes and now I can keep grease on the bearings. It's easy if it's apart.
Click to expand...

While filling the BB with grease is not necessarily a bad idea - think about it. If your spindle was turning in the bearings 24/7, would not the cranks 'n pedals be turning also?
 
That Pablo has got to be the smartest cat on the block! I read all the post and it never accured to me that those bearings wouldn't be turning.I was sitting here thinking ...those bearings would never hold up to that much speed. Duh! dance1
 
haha good point Pablo, maybe a better location for the grease zerk would be on the rear wheel spindle rather then the pedal crank ?
 
If you think I'm smart you should meet my kids....they all think they are 2x as smart as Dad!

If you can somehow get a zerk in the rear, that would be cool, but I would study the downside of drilling back there......and the Shifter kit shouldn't really stress the rear bearings any more than other MB's....well except you end up riding your bike a LOT more.
 
so your kids are like mine ? I thought I had the only kids that were smarter than me ? lol

I will look into a zerk at my rear hub, I cannot really see a downside to this unless u do alot of damage while attempting to drill the hole. But grease will not break down to fast on the bearings , I hate to say this but i have never once greased my bearings mainly cause bikes are cheap, but then untill a month ago I never had a motor on a bike either. I must learn to change with the times . haha
 
After thinking about it, I could be wrong Pablo. I was thinking that it is spinning any time the motor, No wait, I am correct to say that the crank is always spinning if you are running the motor.
Without the jackshaft kit, the engine drives the rear wheel and the crank only spins if you peddle. It's also correct to say that the freewheel is also always spinning.
I also plan to put a grease nipple in my rear rim. I find that once a month I have to tighten up my bearings as I get too much play.The grease is always gone as well. I'm at that point again, if I put on my brakes, I can see the brake pad move the rim over to the side. These wheels were not made to go 40 miles an hour for hours at a time.
 
toytime said:
No wait, I am correct to say that the crank is always spinning if you are running the motor.
Click to expand...

The correct way to think about it: The crank arms are firmly attached to the spindle. This is a fact. We must agree on this. But yet with the Shifter Kit, the pedals don't turn under engine power.

The engine rotation under engine power with the Shifter Kit is transferred to the front chainring via two chains and a solid shaft. This is a fact. We must agree on this.

This front chainring is also solidly connected to another chainring which via a chain drives the rear gears and wheel.

So we have a set of two front chainrings which are bolted together - but these are attached to a freewheel, which rotates freely ON the right crank with engine power. And when you pedal and only when you pedal the freewheel engages and drives the spindle and chain and rear wheel.
 
I had a hard time with that one but I now see that you are correct. I feel stupid right now but yes, I was wrong. If the peddles are not moving, it's not possible for the shaft to be turning.
Boy, my brain had a hard time with that one!
 
Thanks for all the insight. After a few days and just about anything that could go wrong, did. I finally got it put together. And I must say I love it, I climb hills like a bat out of ****. My top 2 gears really don't work well, engine just doesn't seem to have enough power to use them. But I can cruise at top speed with low rev's. Maybe after some fine tuning I'll get them to work better.

OMG it's awesome, it's like a motorcycle, kick start'in it and shifting gears. brnot
 
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