dmfelicia
New Member
So I am almost done with my first build, there is just one problem. The chain will not stay on, it continues to pop off. At first this seems like a simple problem but as I dug and trouble shot I saw this wasn't the run of the mill chain pop off issue.
Here is what happens. If I start to roll the bike with the clutch disengaged I hear a weird grinding type noise (periodic to some extent) then a pop (master link) then the chain is off. This happens at moderate speeds and after a couple feet.
Here is what I have checked. I have made sure that the master link clip opening is oriented opposite to the way the chain moves. Problem persists.
I have adjusted the chain tension (loosened it). Problem persists.
I have lubricated the chain (silicon lube). Problem persists.
The engine cog and wheel sprocket look to be pretty close in alignment although this is just my visual judgment. How do you measure this?
I took it into my workshop and slowly rolled it back and forth until the problem arose. Here are my observations (clues for the mystery):
1)When problem arose I went slow enough that the chain did not pop off. I discovered it seizes up just before failure. (see picture)
2) The chain starts off slack and upon failure is pulled very tight. So much so that with moderate finger pressure their is no visible play (see picture)
3) The spocket doesn't appear to be off alignment in the lateral direction but it definitely is off alignment prior to failure in the forward/back direction so that the chain does not fall properly on the small engine cog. (see picture)
4) There is evidence of grinding but no signs of grinding marks on the chain.
5) One of the links close to the master link has trouble flexing in one direction. Not sure which direction the chain was oriented upon workshop failure.
If anyone has any insights into this mystery I would be much obliged. My theories are that a) that tight link somehow throws the chain off alignment in the front/back direction or b) the chain is in fact off alignment in the lateral direction.
If b) I have no idea how to measure this alignment or correct it.
Cheers
David
I have created an album showing the photos of the problem.
Here is what happens. If I start to roll the bike with the clutch disengaged I hear a weird grinding type noise (periodic to some extent) then a pop (master link) then the chain is off. This happens at moderate speeds and after a couple feet.
Here is what I have checked. I have made sure that the master link clip opening is oriented opposite to the way the chain moves. Problem persists.
I have adjusted the chain tension (loosened it). Problem persists.
I have lubricated the chain (silicon lube). Problem persists.
The engine cog and wheel sprocket look to be pretty close in alignment although this is just my visual judgment. How do you measure this?
I took it into my workshop and slowly rolled it back and forth until the problem arose. Here are my observations (clues for the mystery):
1)When problem arose I went slow enough that the chain did not pop off. I discovered it seizes up just before failure. (see picture)
2) The chain starts off slack and upon failure is pulled very tight. So much so that with moderate finger pressure their is no visible play (see picture)
3) The spocket doesn't appear to be off alignment in the lateral direction but it definitely is off alignment prior to failure in the forward/back direction so that the chain does not fall properly on the small engine cog. (see picture)
4) There is evidence of grinding but no signs of grinding marks on the chain.
5) One of the links close to the master link has trouble flexing in one direction. Not sure which direction the chain was oriented upon workshop failure.
If anyone has any insights into this mystery I would be much obliged. My theories are that a) that tight link somehow throws the chain off alignment in the front/back direction or b) the chain is in fact off alignment in the lateral direction.
If b) I have no idea how to measure this alignment or correct it.
Cheers
David
I have created an album showing the photos of the problem.