help, chain, sprocket

Rogwillsie

New Member
Oct 28, 2008
30
0
0
Seattle, WA
Got a new wheel, installed the sprocket as instructed. The sprocket seemed true when I spun the wheel, both off and on the bike. Also, installed new studs for the motor mounts in the back, tightened the motor mounts. With excitement, I installed the chain and tested it with the bike hung up. The chain comes off at the bottom of the sprocket after a few revolutions of the wheel! What do I do now? It must be an alignment issue, I figure. But how do I align?
 

misteright1_99

New Member
Mar 21, 2008
716
0
0
Treasure Coast, Florida
I use a coathanger mounted to the hub of the wheel (I usually align it off the bike) or the chainstay, bend it out to a point that it just touches the sproocket and spin the wheel an tighten the bolts where the sprocket pushes on the coathanger or loosen the bolts where it doesnt touch.
 

Rogwillsie

New Member
Oct 28, 2008
30
0
0
Seattle, WA
Thanks for your suggestions. I'll look at the alignment. This problem is frustrating because when I first got the engine and installed it, it worked like a charm for several rides before I started having problems and nothing but problems since, including a ruined rear wheel. This time I'll add some detail on my actions. I wanted to install without the tensioner so I put spacers in the back motor mounts to move the engine forward, installed new studs. The chain is not too tight, maybe too loose. Should I reinstall the tensioner? Also, the chain isn't just coming off now, it is climbing on the sprocket and locking. Would come off, I suppose, if I tried to ride it.
 
Sep 20, 2008
1,668
2
0
Clearwater, FL
web.tampabay.rr.com
Rogwillsie,

Your last comment is the clue!

You may have a a sprocket that has not been manufactured properly. My last kit had a poor sprocket.

When the chain rides up on the sprocket teeth...the pitch is wrong!

"Also, the chain isn't just coming off now, it is climbing on the sprocket and locking. Would come off, I suppose, if I tried to ride it."

Jim
 

misteright1_99

New Member
Mar 21, 2008
716
0
0
Treasure Coast, Florida
The instructions that came with my kit stated that you might have to file or grind the sharp edges off the drive sprocket, I did and didnt have your problem. I also didnt use the kit chain or tensioner very long, I installed #41 chain and a spring loaded chain tensioner. Good luck.....
 

xPosTech

The Old Master Motorized Bicycle Builder
Oct 23, 2008
209
0
0
SETexas
New wheel and new engine position. Sounds like a chain line problem.

Is your sprocket dished? If so, you may have reversed it when you mounted it to the new wheel. Whenever I install a sprocket I usually true the rim, true the sprocket, true the rim, etc. My sprockets are not dished, BTW.

Is this on a single speed cruiser with a coaster brake or a multi-speed with derailler? A multi-speed hub with no derailler? All these rear wheels have a different dish. The dish could affect the chain line.

Did you happen to change the type of rear wheel? Change to a wider rim? If so the chain line might change depending on type of wheel, spacers, etc.

Check the chain line with a string from the outside of the drive sprocket to the outside of the rear of the wheel sprocket. There should be no gap or angle in the string at the front of the wheel sprocket. Or just look down the run of the chain from the back. It should run true over both sprockets.

Yes, pictures would help. Show the chain climbing on the sprocket and the run of the chain from the rear.

We'll all get you fixed up.

Ted
 

Rogwillsie

New Member
Oct 28, 2008
30
0
0
Seattle, WA
Ted,
Thanks for your good advice. There is a question I still have. My sprocket is curved and I have it mounted so the teeth are away from the spokes. Is this the right way, or should the teeth be nearer the spokes? A reason i think I may have the sprocket backwards is that when I first installed it, I incorrectly left the outside fiber washer off, which would put the teeth closer to the spokes. It worked fine until the spokes gave out.
Rog
 
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Andyinchville1

Manufacturer/Dealer
Dec 26, 2007
502
1
18
Scottsville, VA
HI,

Have you beveled the teeth on the rear sprocket?....That will usually do the trick assuming you have no stiff links in the chain (the chain line is generally pretty close in most installs and you wold be surprised how far off it can be and still not cause a problem)...

Try beveling and I think you will be happy....(Pic below to show you what I mean....see how the sides of the teeth should angle in on both sides?).

Hope this helps you.

Good luck in your build.

Andrew
 

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Rogwillsie

New Member
Oct 28, 2008
30
0
0
Seattle, WA
Thanks, JasonH and Andrew. My next step will be to turn the sprocket over. I'll also do the beveling. I'll let you know how it works after these changes. Wish me luck.
 

whosworkinthegrill

New Member
Oct 21, 2008
23
1
0
San Clemente, Ca.
I did'nt use a tensioner either and I did run into the same problem as you. I did get it to work out by dumping the outside rubber and using a rubber washer that just fit perfict over the hub that I found at True Value. it gave just the right clearence from the chain. These guys seem to know what they are talking about so I'd try their remedys first.
 

tyrslider

New Member
Sep 26, 2008
958
0
0
RainCity
I think the kit Chain/sprocket set up is junk. The chain is made of rubber and chewing gum and the sprocket mount to the spokes is acceptable at best. Sure it can be made to work but it is a major source of problems. Since I switched to bike chain a little break in (maybe 10 mi) and now it doesn't stretch and it weighs 1/3 of the kit chain. Also I can use a 1/2 link to make both my chains tensioned at the same time. I'm Also opting for rigid sprocket mount to hub on HD axles and HD spokes on HD wheels. The drive system is the only thing I've had repeated problems with.
 

biken stins

New Member
Jul 11, 2008
156
0
0
Dish side in. 415 chain was hard to find. 41 chain works very well and cost less.master links can be found at lowes. try a lawnmower or tractor shop for chain. got mine from Gerish bearing. the center of the sproket needs to fit over your hub. File and moto tool do the trick. Somewhere saw a post on wiring spokes together to so they can take the strain thats put on them. check the posts use search and you will find all sorts of good info. hurry the rainy season is almost here
 

Technocyclist

Motorized Bicycle Senior Technologist
Jul 7, 2008
463
0
0
Asia
Does a Bike Chain fit the sproket? what size? Whats a 415chain?
Yes, a BMX chain 1/2 - 1/8 is the size. I use a BMX YBN(Yaban) half-link chain. It's light, and the most durable I have encountered. Be warned, this chain enjoys breaking your chain breakers. I used a motorcycle chain breaker, and it also got broken. A 415 chain is commonly used in go-karts, tractors and some motorcycles. You can easily get 415 chain in motorcycle spare parts shop and tractor parts shop. :)