[Koend]

Had to use an impact gun on my front sprocket nut to get that sucker loose (also gave it a few good wacks) when replacing chain and sprockets. Now there is a really bad whining noise under acceleration coming from the front sprocket area.. almost sounds like a trumpet and increases in pitch with speed (not rpm’s). Any chance the impact gun caused the countershaft bearing to go bad? Bike was in neutral and I used a screw trough the old chain to hold the sprocket while using the impact on the nut.

The countershaft feels fine when I rotate it with the sprocket off. No play or binding/ grinding.

Chain tension are within specification and wheel is aligned. New 525 chain matching with sprockets

 

[alexei]

Did you change to a different brand? RK perhaps?
I got that whine on an RK at an increasing pitch to speed, all gears.

 

[michael4012]

Impact gun use when removing the front sprocket is perfectly normal, its impossible to have damaged the bearing while applying reciprocal force, as alexei suggests you have an aftermarket sprocket without a dampener which is creating this new to you noise.

 

[Koend]

Thanks for the replies

Chain is DID ZVMX 525 and sprockets are JT 1537-16 and JT 489-40. Front sprocket is the same type as the old one before the noise.
I just can’t understand it’s supposed to have that whining sound? Does it go away after a few miles? It louder than the exhaust and is basically ruining the sound of the bike.

 

[gaz]

what michael said, common with jt countershaft sprocket.

 

[Czano]

Bike was in neutral. That's all you need to know.