jackshaft bearings

GoldenMotor.com

42blue15

New Member
Sep 18, 2008
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St Louis metro, USA
thank you! man,thats one nice set up on your OCC.hope mine turns out that way when its done. what do they call "gear 2" the one that drives the rear end, i dont know what to look for without a name for it. i cant find a specific number to match bike bike chain size. im told a #40 gear for the engine size will work,but what number is gear 2?
Bicycle chain does not have an ANSI number at all; it is narrower than either #40 or #41.

What I did when I built mine (and what Russel seems to have done also) is to buy a #41 sprocket with the correct number of teeth, and then grind it down to where bicycle chain will ride on it properly.
~
 

Russell

Well-Known Member
Apr 19, 2009
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First of all, you can't beat a good sealed bearings for a jackshaft setup. Having said that, I took my bike apart for winter storage.

I was supprised that the open bearings that I bought with the jackshaft kit still had grease on them and never gave me a problem. (I had forced grease into them on the original build).

I rode that bike hard all summer and had only one problem(broken tack weld on freewheel that went to the pedals).

The tack weld was to keep the freewheel from coming off the adapter, as it had to be mounted reverse as the #2 10 tooth sprocket needed to be mounted close to the free wheel.

Of course as Murphys law would have it, it happened at the worst possiable time. I was at JBCRUSIN rally in Pa.(500 mi from home).

When I refer to the sprockets: the motor sprocket drives # 1 sprocket on the jackshaft (18t).
#2 10t (ground down to fit 3/32 bicycle chain going to the 5 speed cluster.

When you say 20" wheel are you talking about the rim or overall tire dia?

My OCC has a 24 overall tire dia. and the gearing as listed works out well for it.
 

MEASURE TWICE

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Jul 13, 2010
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It's OK to remove burrs and raised areas with emery paper. Just probably should tell new folks that "pounding" a shaft through a bearing is never advisable with a ball bearing. You will ruin the bearing. It's OK to press a shaft in or through if you fully support the inner race, and yes you can tap it through if the inner race is backed up well, but it doesn't take much to ruin the thing.

Now back to the regularly scheduled thread.

Besides sanding off burrs if you still have inner bearing surface having overly a lot of force necessary to install on the 5/8 keyshaft, using a tool what is available?

I thought of using a pipe clamp. Those kind that you have a twist handle at one end of the pipe and the other is a slide end stop that adjusts anywhere along the end of the pipe. I remember my dad used it to build in carpentry projects where gluing was needed to be held to dry. Something's were across maybe 2 foot distance. The pipe on the pipe clamp was about 2 1/2 feet.

I'd get the bearing started between the clamp ends to press fit the roller bearing. Then as necessary put these collars just temporarily in place as shims when pushed as far as clamp would limit.

Also for removal I could do the same and maybe a small flywheel puller I have.

I've heard that the outer bearing is OK to press, but not the inner. Also I've hear both need support. I suppose to support both a small thing washer to shim some way that both inner and out get the same force applied to move the bearing.

Any ideas on something to use that won't cost much. As although I tapped one of a set of 10 of the roller bearing I bought with a plastic hammer slight just onto the end of the shaft, I think I will remove it and maybe just discard it. I bought extras, I only am using 4 of them. I would like to have this last a while as it is not simple with my home made bike to change jackshafts bearings out.

I got 2.5 years no trouble with my last bearing in very inclement conditions off-roading. But 1 year ago I heard scraping noise and did not detect exactly that it was the bearings till I saw where creep had occurred on the inner bearing surface when disassembling to change the configuration. One jackshaft had deep enough marks that I attribute it to the belt tension on the bearing and that lube of the seal bearing probably ran out during the last year of use and it froze up intermittently.

A tighter fitting bearing to a degree will prevent creeping, so I would not do again sanding down for bearing to just slip on without any force. I also have beside new sealed bearings, two new jackshafts, but the clearance is if not 0, is on the plus side. Well, maybe not, as the bearing spins with ease the same as prior to installation, but I am unhappy with my actions of using even a plastic surface tapping on a bearing.

Optionally I could make fit less snug by sanding jackshafts and use on bearings the Loctite Bearing Mount stick compound to prevent creep. It just is the uneven removal of metal on the shaft without the use of a lathe that makes me think not again. Also removal then becomes a issue, but I though ahead how I could remove the whole shaft all still assembled away from the bike and put on a work bench where I could use a press of some kind or heat and cooling as well. On that note maybe I would put the jackshaft in the freezer prior to assembly?
 
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MEASURE TWICE

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http://www.homedepot.com/p/BESSEY-H...gclid=CLb2sLaexc4CFVBbfgod5MwAcg&gclsrc=aw.ds

http://www.homedepot.com/p/LDR-Indu...teel-Schedule-40-Cut-Pipe-306-12X18/100545904

I was thinking if these would work if there is enough surface on the jaws after removing the rubber protective parts. I will look at them at the hardware store and see as the web page does not exactly in the picture tell. I'll bring a calipers to measure. Also some way of also stabilizing while clamping is something I have to figure out before I go this route. Possibly both sanding and using this set up as a press fit bearing.

From the picture I estimate the jaws minus the rubber covers to be at least as large as the thread hole on the clamp for 1/2 inch black pipe. 1/2 inch black pipe outer diameter is 0.84 inch so this larger than the 5/8 shaft, but actually 2 inch square or larger jaw is necessary for outer bearing surface. So I'll look for something else. I'm not sure though if 3/4 size pipe clamp is going to be much different. Adapting it does not seem likely.

For larger stuff found this:

https://youtu.be/Uab9VncBIUg
 
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MEASURE TWICE

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https://www.youtube.com/watch?v=YRy_9awUo_A

I've seen the videos on Youtube of this guy working on engine and mechanical stuff. This video is of bearing removal with puller. I have a few small flywheel pullers and will use then if I can. Installation mentions tapping with hammer.... but of course I've heard differently on the web about this.

Still I thought of a press by using a drill press I have but do not want to damage the press as it really is not an arbor press, is just for drilling. If I sand the oversize 5/8 shaft down some, then maybe the drill press adapted will be a useful tool and not get damaged in the process. Would not want to have to replace the bearings in the drill press for the misuse of it ironically;)
 

Ghost0

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Mar 7, 2008
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Bellingham, WA
As Pablo mentioned the instructions are clear about cleaning the shaft up so the bearings can be easily slid along the shaft without tools. You should never need a hammer or any other tool to assemble or disassemble the jackshaft assembly. Typically best practice is to spend the most time with a file right at the ends of the shaft as the machining process to cut them can cause a mushrooming effect on the ends. Typically the middle of the shaft should require very little attention. However due to variance in the manufacturing process sometimes you can get one that will require more sanding than others. Also ensure you create the flat spots for the set screws as noted in the instructions. If you do not the tightening of the set screws will create a burr sufficient to make it impossible to remove a bearing or the sprocket for that matter. Bottom line is you should never have to use a hammer or pulling device to assemble or disassemble the jackshaft assembly. If you do then it was not assembled correctly in the first place.
 

MEASURE TWICE

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Jul 13, 2010
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Thanks!

The use of a Bearing Mount Compound not for damaged shaft but a new shaft to prevent creeping?

MT