Bent (output) shaft sindrome

Hi there.

I was involved recently in changing sprocket and chain of my Honda
hornet 600. The chain i had on was the original from Honda and lasted a
honerable 10966 miles. As I'm new to maintenance jobs and repair jobs i
have a question for the expert audience of this group.

I removed chain and sprockets from the motorbike and installed the new
ones. Once I've aligned the rear wheel i checked for tight spots and
check the tension in different parts of the wheel. Once i was satisfied
with the result i wanted to see if everything looked fine. With the
bike on the rear wheel stand i started the engine and putted it in 1st
gear. I sat down behind the rear wheel looking the rear sprocket. The
rear sprocket had no lateral oscillations and i was perfectly aligned.
Looking at the chain getting feed to the drive sprocket i noticed the
chain oscillating slightly from left to right as the chain engaged in
the drive sprocket (this is only 3-4 millimetres but still very
evident). When i inspected the old drive sprocket, which was installed
on the output shaft, i noticed that it was not rotating perfectly, but
it had some anomalies, with slight oscillations.... I associated this
with the fact that the sprocket were worn.

Now i installed a new drive sprocket and there is still oscillations.
Is this normal or the bike could have a bent output shaft? There is no
oil leak on the output shaft, but will it quickly wear the chain? Could
tell me if the drive sprocket should be aligned straight without
oscillations or is it normal to have some oscillations.

Your help is very appreciated.

 

Are the insides of the link plates on the old chain worn to where they
are polished and shiny bright? That indicates sprocket misalignment.

I noticed the chain walking from side to side on my GSXR-750 and took
steps to shim the countershaft sprocket and the rear sprocket, but the
chain *still* walks from side to side.

Why? It seems that the original equipment chain had thicker side plates
and the aftermarket chain has thinner sideplates. So the chain walks
from side to side as the rear wheel turns.

It's very difficult to bend a transmission countershaft, but I suppose
you could manage it if you had a hydraulic press and applied tons of
force to the shaft.

You could easily determine whether the shaft is bent by watching the
end of it as it rotates. There is probably a pilot hole on the end of
the shaft that you can see. It's for turning the shaft in a lathe.

If you mark the exact center of the with a dab white paint and run the
engine and the
white mark appears to go around in a circle, the shaft is bent.

 

You are right, i've replaced the original sproket with aftermarket one.
The drive sproket had ticker side plates, i remember that. i'll buy a
original drive sproket and check if the oscilations are reduced.

Thanks for your help