Loco runs smoother in one direction than other

[philsandy]

I have a couple of Bachmann steam locos with Loksound V4, that don't run quite as smooth in reverse as when going forward. It's hardly noticeable really, and quite difficult to pin point what the difference is.

It is not apparent at very slow speeds , only  when they reach step 20 upwards. The only way I can describe it is when going forward it is a very consistent smooth flowing motion of wheels and valve gear, in reverse although it does not jerk or even have a slight tight spot, it just does not look as smooth on the eye.

Is this something that could be eliminated by altering CV values eg. 54, 55?  which I have experimented with. Or is it just that some models/motors do have this characteristic? 

[Bucoops]

In before anyone else asks - does it do the same thing on DC?

[Pete the Elaner]

Asymmetrical running sounds more likely to be a physical issue.

 

A CV change should be applied equally in both directions, but it is possible that the motor/mech performs differently in each, causing any feedback circuit to react differently, so it may mask the issue a little.

[Crosland]

There was someone on the 2mm forum with a similar problem but in reverse https://www.rmweb.co.uk/community/index.php?/topic/38833-any-question-answered/&do=findComment&comment=3662611

[Hamburger]

3 hours ago, philsandy said:

I have a couple of Bachmann steam locos with Loksound V4, that don't run quite as smooth in reverse as when going forward.  . . . .

. . . . is it just that some models/motors do have this characteristic? 

Because it is a steam loco - do you run it forward most of the time?

Thus, over time, the mechanical parts (gears, brushes etc.) are only "smoothed" on one side, resulting in smoother running only in one direction.
You should try to run your locomotives in reverse for about an hour at half speed.

 

 

[philsandy]

Thanks for all your replies. 

I tried running one loco on DC and the difference was very noticeable, it ran very smoothly. So then spent a considerable time adjusting (again!) CV's 53, 54, 55, and eventually got it running much better.

However I think one loco does have a mechanical problem, ie. it's an EM conversion, and I think there may be just not enough clearance between front driving wheel crank pins and the valve gear.