Rear Sprocket Issues

T

techtiger

New Member
I purchased a kit 2011 grubee skyhawk gt5. I am having extreme issues with the rear sprocket. Every chain I put on falls off the rear sprocket. I have the sprocket centered and have it so it does not wobble. It has got me so frustrated. I really want to ride this bike for more than 2 minutes. So if anyone near springfield MA can help or know a post that can help please give me advice.:-||
 
I'm not near Springfield but I can tell you this. Chain/sprocket alignment and chain tension must be correct or you'll have the problems you're having.

When I say alignment I'm talking about an absolutely straight line between the engine drive sprocket and the rear wheel driven sprocket. If you're using a chain tensioner it too must align with the chain path.
Roller chains will not run around corners or bend. You might have the rear sprocket installed so it is centered on the rear hub and with no wobbles but if it is not aligned perfectly with the engine drive sprocket or the tensioner is dragging the chain off to either side you're going to have problems. All kit chain tensioner brackets need to be bent/twisted to allow for the taper in the chain stay. Clamped on as it came in the kit it will automatically misalign the chain.

Proper tension is also important. 1/2 to 3/4" of slack. No more, no less.

Tom
 
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Another thing to look for, is that after a chain has been thrown from a sprocket, it can be slightly damaged just enough to keep coming off easier each time after. :/
 
What I've learner to do is get the sprockets aligned and the chain adjusted then roll the bike by hand watching the chain as it rolls over the tensioner. If the chain if not rolling centered on the tensioner wheel bent the mount till it does, I use the best chain found locally. #41 has worked well.
 
Don't forget to put rubber pieces in between the chain tension mounts and the frame. Thats to keep the chain tension in place.
 
Hoze513 said:
Don't forget to put rubber pieces in between the chain tension mounts and the frame. Thats to keep the chain tension in place.
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I'm sorry, Hoze, but I'm going to have to disagree with your advice. Eventually the rubber will compress and the bracket will loosen. If you use this method you need to constantly check the tightness of the tensioner bracket. Over time, it WILL loosen.

There are other ways to secure the bracket to the frame that are more permanent.

Tom
 
Ok How do I fit the rear sprocket close to the hub with a thinner substitute rag joint? Is it possible to run without the rag on one side? I noticed if I could remove it and this was possible it would align perfectly.
 
I don't understand exactly what you are talking about, you need the rag joint to protect the spokes. One piece behind the sprocket the other behind the spokes, squeezing the spokes between the two. Only the three bolt plates are used inside against the rag joint. If you can post pictures someone will give help.
 
2door said:
I'm sorry, Hoze, but I'm going to have to disagree with your advice. Eventually the rubber will compress and the bracket will loosen. If you use this method you need to constantly check the tightness of the tensioner bracket. Over time, it WILL loosen.

There are other ways to secure the bracket to the frame that are more permanent.

Tom
Click to expand...

Thanks, If you know others way let me know. But without having to drill in the frame. So far It has been holding on strong, all year. But Iam also a Newbie, and only Know what I have seen on this forum. I also have a spring tension. That hooks on the side of the motor. I have not put that on, because It barley hits the petal. Thanks
 
I hope this helps. Let me explain better. The rubber piece thats on the two half moon plates is pushing the sprocket out of alignment. Without that piece there I would have perfect alignment. I also noticed the dust cover or metal plate near the center where the spokes connect had a slight bevel by like 1/100th of an inch not allowing the sprocket to be completely flush to the hub. So my question is if I should grind out the sprocket a bit to fit it over and then find an inner tube to use a thinner barrier in place.
http://img576.imageshack.us/img576/7100/img20120703174722.jpg
http://img140.imageshack.us/img140/8647/img20120703174649.jpg
http://img194.imageshack.us/img194/8555/img20120703174635.jpg
 
I have had to open up the sprocket on a couple of bikes, if you have a die grinder with a carbide barrel rasp its not hard. You haave to make sure to keep the hole centered.
 
techtiger said:
I hope this helps. Let me explain better. The rubber piece thats on the two half moon plates is pushing the sprocket out of alignment. Without that piece there I would have perfect alignment. I also noticed the dust cover or metal plate near the center where the spokes connect had a slight bevel by like 1/100th of an inch not allowing the sprocket to be completely flush to the hub. So my question is if I should grind out the sprocket a bit to fit it over and then find an inner tube to use a thinner barrier in place.

I had the same problem as you. The only way I could keep the sprocket straight, was to take out the outside rubber piece. So thats what I did. Been running great all year. I saw this on Daxthats web site ( videos). He said on video that, he has been doing all his bikes like that. And never had a problem.
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HI,

Beveling the sprocket teeth will help it feed and practically eliminate chain "jump offs"

This is the case even if the sprocket is out of alignment and wobbles a little.

Hope this helps

Andrew
 
Changed the back rim and hub to fit the sprocket. Rag joint on the outside still seems to be pushing the sprocket a bit left out of alignment. Gonna check on it tomorrow. Hopefully be riding it soon.
 
This is why this forum rules.
Thanks for the Dax reference.
I'm having major issues with aligning my 60 tooth on my trike.
And I'm sure removing the rag joint will help.
And I've done many of these.
Just proves that there's always more to learn!
 
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