Thoughts on mechanically improving Bachmann 2-8-0

[Iain]

I have a Bachmann 2-8-0 that has a wobble in it causing binding, so I've got to pull it apart.  Does anyone have any thoughts on improving the performance?  I figure @mmagliaro may have some thoughts on replacing the motor.  I'm not sure I want to do the gearhead route, as I want to be able to 'cruise' at around 45 smph.

[djconway]

My thoughts:
Check the quartering.
Check that the traction tire is round.
And here is where it gets a little more difficult -- check that wheels are square to the shaft.

[mmagliaro]

I'll say at the outset that I wouldn't touch the motor in that thing.  The Bachmann 2-8-0
has a lot of gear reduction and a pretty darn good skew-wound 5-pole motor in it already.
It is not worth remotoring.

More importantly, it would not solve your problem!

I like DJ Conway's suggestions.   I would think the quartering would be more likely than the other
two suggestions, but they are all possible.

I have a few questions.   Okay... I have a lot of questions.   

1. Did it always have this "wobble"?  Are you sure it isn't something that has always been there,
which you have become more sensitive to as you have collected other engines and become
more demanding of how you expect them to run?
I say this because I know I'm guilty of it.  Things I thought ran "great" in 1998 look terrible to me
now because we have all become so spoiled and accustomed to silky-smooth, perfect motion
and creeping at sub-5 mph speeds.

2. I would ask you to describe the wobble more, but that will go down a rabbit hole of us
all trying to really understand what it is doing.  Any chance you can shoot some video, hopefully
very close up, of it doing this, so we can see it?

Failing that, is this "wobble":

a) bobbing up and down, most noticeable if you watch the cab roof?
b) side to side, sort of wiggling and canting back and forth between the rails?

Does it bob or wobble exactly once per driver revolution?

How do you know the wobble is causing the binding?  How do you know it IS binding?  Does it
exhibit a "hitch" in its motion once per revolution of the drivers?  Very often, if a driver is out of quarter,
when it comes around to the tight spot, the rod won't be able to move freely because the
location of the driver hole is a little off, and having nowhere else to go, it will push the engine upwards.
Then when the wheel turns past that spot, the engine comes back down.  This can look like a
bobbing up and down that is also synchronized with a bind at that point.

If you can creep it along just to where it binds and stop it, and then without moving the engine
use fine tweezers to see if you can
wiggle the side rod on both sides, and if one or both of them has no play in it at all around the crankpins,
then that strongly suggests a quartering problem.

[VonRyan]

My Bachmann 2-8-0 wobbles as well. It's a pre-DCC model, that I had to hard-wire a decoder into.
But, it doesn't bind, so I don't care that it wobbles. As long as it keeps running.

[Iain]

My thoughts:
Check the quartering.
Check that the traction tire is round.
And here is where it gets a little more difficult -- check that wheels are square to the shaft.

Thanks, but wasn't asking how to diagnose the issue; I was asking what I could do now that I have it apart to make it run better as if it did not have a problem.

I'll say at the outset that I wouldn't touch the motor in that thing.  The Bachmann 2-8-0
has a lot of gear reduction and a pretty darn good skew-wound 5-pole motor in it already.
It is not worth remotoring.

More importantly, it would not solve your problem!

I like DJ Conway's suggestions.   I would think the quartering would be more likely than the other
two suggestions, but they are all possible.

I have a few questions.   Okay... I have a lot of questions.   

1. Did it always have this "wobble"?  Are you sure it isn't something that has always been there,
which you have become more sensitive to as you have collected other engines and become
more demanding of how you expect them to run?
I say this because I know I'm guilty of it.  Things I thought ran "great" in 1998 look terrible to me
now because we have all become so spoiled and accustomed to silky-smooth, perfect motion
and creeping at sub-5 mph speeds.

2. I would ask you to describe the wobble more, but that will go down a rabbit hole of us
all trying to really understand what it is doing.  Any chance you can shoot some video, hopefully
very close up, of it doing this, so we can see it?

Failing that, is this "wobble":

a) bobbing up and down, most noticeable if you watch the cab roof?
b) side to side, sort of wiggling and canting back and forth between the rails?

Does it bob or wobble exactly once per driver revolution?

How do you know the wobble is causing the binding?  How do you know it IS binding?  Does it
exhibit a "hitch" in its motion once per revolution of the drivers?  Very often, if a driver is out of quarter,
when it comes around to the tight spot, the rod won't be able to move freely because the
location of the driver hole is a little off, and having nowhere else to go, it will push the engine upwards.
Then when the wheel turns past that spot, the engine comes back down.  This can look like a
bobbing up and down that is also synchronized with a bind at that point.

If you can creep it along just to where it binds and stop it, and then without moving the engine
use fine tweezers to see if you can
wiggle the side rod on both sides, and if one or both of them has no play in it at all around the crankpins,
then that strongly suggests a quartering problem.

It turns out the gear axle was whack; gonna have to order a replacement.  This locomotive has never run properly from the day I bought it.  It's kind of noticable because it moves a couple inches and stops.  Not something needing an experienced eye.

[peteski]

I have a Bachmann 2-8-0 that has a wobble in it causing binding, so I've got to pull it apart.  Does anyone have any thoughts on improving the performance?  I figure @mmagliaro may have some thoughts on replacing the motor.  I'm not sure I want to do the gearhead route, as I want to be able to 'cruise' at around 45 smph.

Wow!  That is confusing.  Nowhere in your initial post you actually asked for instructions on how to take the model apart.  The only direct question I see from you in that post is Does anyone have any thoughts on improving the performance?  That is a very direct and specific question. You did mention taking it apart so I've got to pull it apart, but that seems to imply that you know what you're doing. 

The entire post seems to read as follows:  My loco has a wobble. I have to take it apart to find the cause and fix it. While I'm at it, does anyone have any ideas for improving its performance?

[mmagliaro]

... snip ...

The entire post seems to read as follows:  My loco has a wobble. I have to take it apart to find the cause and fix it. While I'm at it, does anyone have any ideas for improving its performance?

This is exactly how I interpreted it and that's why I answered the way I did.

[SkipGear]

To the improvement question......NO, there is nothing to do.
When these loco's are right, they are one of the best running N scale steam locos. They get better with age. I have one that will pull close to 80 cars on level track and runs smooth as silk. It also happens to have close to 20 hours on it.

[Iain]

The entire post seems to read as follows:  My loco has a wobble. I have to take it apart to find the cause and fix it. While I'm at it, does anyone have any ideas for improving its performance?

This, entirely.

Welp, thanks kindly, y'all.