Chain drop issue help?

TheSignGuy

Member
Nov 24, 2014
452
7
18
seattle, wa
Hey so I went on my first long term ride yesterday about 16 miles.

If I'm gentle on the throttle about H/O/T my chain jumps off once or twice a ride at wot around general area if I gun it it throws the chain quicker any ideas for to stop the chain drop? I'm aware on two ideas and easier fixes that cn prevent this, I need a tensioner, and the exhaust has to be pulled off where the orginal suzuki fa50 rim use to be there is no lock nut so sometimes the rear hub/sprocket free slides in a stationary position.


Next problem at low rpm wot the engine stalls out unless you build to 1/2 to 3/4 the speed up then gun it.


new link for eyes only:

https://youtu.be/58owKmPoCgE
 
Last edited:

2door

Moderator
Staff member
Sep 15, 2008
16,326
124
63
Littleton, Colorado
Chain derailing is the result of sprocket misalignment and/or wrong chain tension. Misalignment being the most common. The drive and driven sprockets MUST be aligned. Roller chain doesn't like any offset and it will only run in a straight line.

Use a straightedge and lay it against both sprockets. If the straightedge doesn't touch the sprockets in four places the sprockets aren't aligned.

Tom

Tom
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
6,615
421
83
Los Angeles, CA.
There are many reasons for a chain coming off...

The rear sprocket doesn't spin perfectly true & centered,
chain has too much slack,
chain is slightly bent from coming off in the past,
chain is too close to the tire & is bouncing off the side of the tire at high speed,
sprocket teeth are bent from chain coming off in the past.

Please make sure all these problems are fixed. ;)
 

TheSignGuy

Member
Nov 24, 2014
452
7
18
seattle, wa
Chain derailing is the result of sprocket misalignment and/or wrong chain tension. Misalignment being the most common. The drive and driven sprockets MUST be aligned. Roller chain doesn't like any offset and it will only run in a straight line.

Use a straightedge and lay it against both sprockets. If the straightedge doesn't touch the sprockets in four places the sprockets aren't aligned.

Tom

Tom


By eye it's slightly off but not enough to throw the chain but I did notice today the chain is slightly bent. I bent it back but still not razor blade streight.

Someone quoted today on a pit stop "A motorcycle chain would work better for this.

Problem with their theory is that the motorcycle chains are wider toothed in between the sprocket gaps.

They do have higher tensile strength but I'm using prodominatly bicycle gearing.


Eventually I will have to have a new sprocket bolt on assembles built to get more speed. My gear ratio needs improvement by 1/4th current top speed is 15.5 miles an hour phone GPS verified via ap I will post a photo of it in a bit.
 

TheSignGuy

Member
Nov 24, 2014
452
7
18
seattle, wa
There are many reasons for a chain coming off...

The rear sprocket doesn't spin perfectly true & centered,
chain has too much slack,
chain is slightly bent from coming off in the past,
chain is too close to the tire & is bouncing off the side of the tire at high speed,
sprocket teeth are bent from chain coming off in the past.

Please make sure all these problems are fixed. ;)

The teeth on most bikes are always slightly twisted on some models but non of them are bent out of alignment the previous sprocket that was orginally equipped on the wheel is also welded over top of the manufactures sprocket. So it's double toothed but they are aligned ones just shorter in theory could be riding on the oem teeth and kicking it off from vibration.
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
6,615
421
83
Los Angeles, CA.
I've built hundreds of bikes with very few chain issues... There has to be one of these mechanical issues going on with your bike for it to keep throwing the chain!

Carefully check everything we've mentioned & eliminate all these possibilities first. ;)
 

TheSignGuy

Member
Nov 24, 2014
452
7
18
seattle, wa
I've built hundreds of bikes with very few chain issues... There has to be one of these mechanical issues going on with your bike for it to keep throwing the chain!

Carefully check everything we've mentioned & eliminate all these possibilities first. ;)

https://youtu.be/58owKmPoCgE


Here is the link should I be concerned about a tensioner and quality of the chain this was a old spare my wife got out of her cleaning business from a move out was just good old junk. I want the best quality I after tomarrow I should have some throw around change for bills.