| | | Motorized Bicycle General Discussion Topics on bicycle engine kits, help articles, repair and modifications for your motorized bicycles | jack shaft on a cruiser Discussion at Motorized Bicycle Engine Kit Forum in the Motorized Bicycle General Discussion forum. Well I just got a jack shaft and have run into my first problem. Installing the cranks, I took my ...  | | 
04-08-2009, 08:01 PM
|  | Motorized Bicycle Elite Member | | Join Date: Feb 2009 Location: Arroyo Grande, Ca
Posts: 113
| | jack shaft on a cruiser 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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04-08-2009, 08:07 PM
|  | Motorized Bicycle Elite Member | | Join Date: Feb 2009 Location: Arroyo Grande, Ca
Posts: 113
| | Re: jack shaft on a cruiser Never mind, just needed a bigger hammer. I'm sure I'll have more questions though as I go along. 
__________________ Sun Tzu: To secure ourselves against defeat lies in our own hands, but the opportunity of defeating the enemy is provided by the enemy himself. | 
04-08-2009, 08:47 PM
| | Motorized Bicycle Elite Member | | Join Date: Mar 2008 Location: Ontario
Posts: 551
| | Re: jack shaft on a cruiser 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. | 
04-08-2009, 09:21 PM
|  | Motorized Bicycle Elite Member | | Join Date: Feb 2009 Location: Arroyo Grande, Ca
Posts: 113
| | Re: jack shaft on a cruiser 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. 
__________________ Sun Tzu: To secure ourselves against defeat lies in our own hands, but the opportunity of defeating the enemy is provided by the enemy himself. | 
04-09-2009, 06:42 AM
|  | Master Bike Builder & Forum Sponsor | | Join Date: Dec 2007 Location: Duvall, WA PNW
Posts: 2,683
| | Re: jack shaft on a cruiser Quote:
Originally Posted by toytime 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. | 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? | 
04-09-2009, 07:06 AM
|  | Motorized Bicycle Elite Member | | Join Date: Oct 2008 Location: alabama
Posts: 266
| | Re: jack shaft on a cruiser 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!  | 
04-09-2009, 07:13 AM
|  | Motorized Bicycle Elite Member | | Join Date: Mar 2009 Location: penn state
Posts: 213
| | Re: jack shaft on a cruiser haha good point Pablo, maybe a better location for the grease zerk would be on the rear wheel spindle rather then the pedal crank ?
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04-09-2009, 07:20 AM
|  | Master Bike Builder & Forum Sponsor | | Join Date: Dec 2007 Location: Duvall, WA PNW
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| | Re: jack shaft on a cruiser 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. | 
04-09-2009, 07:29 AM
|  | Motorized Bicycle Elite Member | | Join Date: Mar 2009 Location: penn state
Posts: 213
| | Re: jack shaft on a cruiser 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
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04-09-2009, 10:36 AM
| | Motorized Bicycle Elite Member | | Join Date: Mar 2008 Location: Ontario
Posts: 551
| | Re: jack shaft on a cruiser 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. | | Thread Tools | | | | Display Modes | Linear Mode |
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