Bachmann class 08 problem

[SimoninCalgary]

I chipped and ran in my Bachmann class 08 shunter, runs well in one direction, but in the other the motor 'chatters' like cardboard in a bike's spokes.  Speeds up as the motor speeds up.  The worm gear engages smoothly.  Any ideas people? 

[34theletterbetweenB&D]

Could be as simple as the cardboard 'flipper' on the bike spokes.

Something internal dragging on the flywheel: take body off and see if the noise disappears.

A pick up wiper dragging on the spokes or some irregularity on the wheel back.

 

Both these can be one direction only, as the dragging component sits slightly differently with change of direction. Plenty more possibie causes of course.