Misaligned sprockets.

DSpawnZ

New Member
Jun 18, 2016
4
0
0
Argentina
Hi to all. First of all I'll say sorry for my english as my native language is spanish. I'll try to be as clear as possible.
Yesterday I've finished my motorized cruiser. It's a standard cruiser bike frame.
Chain makes a horrible grinding noise, and I've noticed rear sprocket is out of alignement with front sprocket about half an inch or so.
I can't seem to figure out how to move the engine because I can't move the rear sprocket.
Rear wheel is a 26 inch standard cruiser with internal brake in the rear hub.
I've mounted the sprocket with a sandwiched grommets mount.
One inside the spokes and another outside.
If I look the bike from behind either engine needs to move to the right or rear sprocket needs to move to the left but this is impossible because sprocket and chain would hit the frame.
Really I don't know what to do as I can't figure out how to move the engine on the frame. Only possible solution would be make a mounting plate for the seat pipe and install it between the engine and frame.
Any experience would be of great help.

Thank you.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
156
63
USA
first thing to check is whether your rear sprocket is dished in or out (instructions for mtn bike in kits say in, but for fat tire bikes, out is better)

that said, th chain can be very forgiving about misalignment in the top run as long as the sprocket teeth are fairly thin at the tips (older, fat tooth sprockets can be filed or ground a bit thinner right at the tips so teeth find holes in chain better)

in the bottom run, the tensioner can be bent a bit to point the slack chain more directly onto the teeth
 

DSpawnZ

New Member
Jun 18, 2016
4
0
0
Argentina
first thing to check is whether your rear sprocket is dished in or out (instructions for mtn bike in kits say in, but for fat tire bikes, out is better)

that said, th chain can be very forgiving about misalignment in the top run as long as the sprocket teeth are fairly thin at the tips (older, fat tooth sprockets can be filed or ground a bit thinner right at the tips so teeth find holes in chain better)

in the bottom run, the tensioner can be bent a bit to point the slack chain more directly onto the teeth
Thanks for your answer. Rear sprocket is dished out. I can't take it any outer because it almost touches the frame. Will post pictures tomorrow.
And also will check teeth if they are fat or thin.
And will bend the tensioner too and report.

Thanks
 

crassius

Well-Known Member
Sep 30, 2012
4,032
156
63
USA
in the old days (search back for threads 4 or 5 years ago) the sprockets were very fat toothed & many folks had problems - one thing we used to do was space the axle off to left, then dish the spokes to put tire back in middle

with you almost hitting frame now, that would just cause more problems - instead, I used to grind the rear teeth almost knife-edge sharp so they could easily find the gap in chain in side-to-side direction
 

DSpawnZ

New Member
Jun 18, 2016
4
0
0
Argentina
Updated with some pictures. Motor seems off-center. Will take it down and check.





Update: Looking good. Took me almost half day to discover that I had to rotate the motor about 3 degrees counter-clockwise. I really don't know why, but as my frame is 38mm had built a front plate to mount it, and made holes not symetrical to rotate the motor. Grinding and noise in the chain has gone away and also I was able to get rid of chain tensioner too!.
I've drove the bike for about half a mile and tomorrow will test it more time and check if every nut and bolt is in place. It's been a long and happy day for me.
 
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