I have my motorbike since December and have had very few problems. However for the past month the chain has been jumping off the drive sprocket. I have adjusted the tensioner and shorten the chain but that hasn't worked. So any ideas or suggestions would be appreciated.
Chain popping off drive sprocket
- Thread starter bike
- Start date
There are a couple of things to check:
REAR SPROCKET WOBBLE (runout)
Get someone to help you lift the rear wheel of the ground and spin the rear wheel with the clutch held in. (motor is not running)
Look at the rear sprocket and see if it has a wobble to it, left to right.
It should wobble back and forth no more than about an eight of an inch.
Tighten the corresponding bolts on the rag joint to bring any spots that wobble out away from the wheel.
You may need to loosen some just slightly to bring any spot that wobbles in toward the wheel .
Fiddle with it until you get it running as true as you can. It can be somewhat of a pain, but if the sprocket isn't straight the chain will always jump off.
REAR SPROCKET NOT CONCENTRIC TO WHEEL
If the chain gets loose, tight, loose, tight as you spin the rear wheel it is not centered properly to the rear wheel .
You may need to loosen all of the rear sprocket bolts and re-center the sprocket.
CHAIN STRETCH
The chain will always stretch as it gets worn in.
Use a ruler and set the 0 inch mark exactly on a pin that rivets the chain together,.
Each rivet or pin should be exactly 1/2 inch from the next.
Look at the 12" mark and see if it falls exactly on a pin.
If the chain has grown to the point where the nearest pin falls more than 1/8" off the nearest 1/2"
mark on the ruler, get a new chain.
Get a decent one. #41 chain is a bit wider and more forgiving to poorly aligned sprockets.
TENSIONER
Make sure it runs perfectly parallel to the chain.
Sometimes it need a slight twist, since the bike frame (chainstay) runs outward to the rear wheel.
ENGINE NOT STRAIGHT IN FRAME
Look down the centerline of the bike and see if the engine has shifted left, or right causing the front and rear sprockets to be misaligned. Loosen the ngine mounts and adjust and re-tighten
CHAIN NOT SEATED INTO SPROCKETS BECaUSE SPROCKET IS SLIGHTLY TOO WIDE FOR CHAIN
Chances are this isn't it because you've been riding successfully for months before the problem occurred
I hope something here hits home for you. I know chain jump offs are aggravating. GOOD LUCK
don't give up
REAR SPROCKET WOBBLE (runout)
Get someone to help you lift the rear wheel of the ground and spin the rear wheel with the clutch held in. (motor is not running)
Look at the rear sprocket and see if it has a wobble to it, left to right.
It should wobble back and forth no more than about an eight of an inch.
Tighten the corresponding bolts on the rag joint to bring any spots that wobble out away from the wheel.
You may need to loosen some just slightly to bring any spot that wobbles in toward the wheel .
Fiddle with it until you get it running as true as you can. It can be somewhat of a pain, but if the sprocket isn't straight the chain will always jump off.
REAR SPROCKET NOT CONCENTRIC TO WHEEL
If the chain gets loose, tight, loose, tight as you spin the rear wheel it is not centered properly to the rear wheel .
You may need to loosen all of the rear sprocket bolts and re-center the sprocket.
CHAIN STRETCH
The chain will always stretch as it gets worn in.
Use a ruler and set the 0 inch mark exactly on a pin that rivets the chain together,.
Each rivet or pin should be exactly 1/2 inch from the next.
Look at the 12" mark and see if it falls exactly on a pin.
If the chain has grown to the point where the nearest pin falls more than 1/8" off the nearest 1/2"
mark on the ruler, get a new chain.
Get a decent one. #41 chain is a bit wider and more forgiving to poorly aligned sprockets.
TENSIONER
Make sure it runs perfectly parallel to the chain.
Sometimes it need a slight twist, since the bike frame (chainstay) runs outward to the rear wheel.
ENGINE NOT STRAIGHT IN FRAME
Look down the centerline of the bike and see if the engine has shifted left, or right causing the front and rear sprockets to be misaligned. Loosen the ngine mounts and adjust and re-tighten
CHAIN NOT SEATED INTO SPROCKETS BECaUSE SPROCKET IS SLIGHTLY TOO WIDE FOR CHAIN
Chances are this isn't it because you've been riding successfully for months before the problem occurred
I hope something here hits home for you. I know chain jump offs are aggravating. GOOD LUCK
don't give up
"Make sure your idler is tightened very tight before you ride, if not, it will go into your wheel and destroy many spokes" - the voice of experience
Make sure your sprockets are in good condition, no bent teeth, nothing out of line.
Like TimB said, make sure your rear sprocket is centered on the hub(no up and down movement) and that it is parallel to the wheel(no side-to-side movement).
Make sure everything is centered(engine, idler, sprockets)
Make sure there are no stiff links in your chain, consider buying a new one, these stock chains aren't the best quality(or even good quality). Use chain wax or oil on your chain- NOT WD 40
Make sure your sprockets are in good condition, no bent teeth, nothing out of line.
Like TimB said, make sure your rear sprocket is centered on the hub(no up and down movement) and that it is parallel to the wheel(no side-to-side movement).
Make sure everything is centered(engine, idler, sprockets)
Make sure there are no stiff links in your chain, consider buying a new one, these stock chains aren't the best quality(or even good quality). Use chain wax or oil on your chain- NOT WD 40
