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Friday, I spent the entire day trying to tweak the Tsunami advanced settings in my Bachmann 4-8-2. I finally got it close to where it was perfect, but the loco sometimes wanted to be a little jerky at startup. This Bachmann, like all I have bought, has always had a bit of jerkiness to it. It may go unnoticed by many, but it drives me up the wall.
I then decided to take a deep breath and completely disassemble it...I mean all of it. I first performed the ole "drive wheels on glass" check and saw that the wheels had resistance and also would try to hang at a certain degree of turn. What I found was not obvious (there were no rubbing rods and so on) but after removing the main driver rod on one side, the wheels moved with ease. The alignment of the rod's slider mechanism seemed fine, but the smaller piston rod going into the cylinder was slightly skewed causing the whole slider assembly to bind. Slightly forming the piston rod's slider and using a drill bit to ream the hole very slightly cleared the bind and now the wheels freely turn. I am still suspicious of the whole front assembly actually causing this problem. I will look into that a bit more before assembly and let you know.
One thing thats been mentioned with some regularity of the sound equipted steamers is that they do tend to have a bit higher starting voltage than standard DC equipted locomotives.
Depending on where you pick up your steamers, you may have bent the siderods. It's a VERY commom problem that if not treated properly can destroy your engine. Basically just make sure the siderod bits are straight and free when assembled. If they aren't, take a small flathead screwdriver and GENTLY bend the offending siderod bit outward until it's pretty straight, and your problem should go away.
the "glass" test wouldn't be a bad idea for the siderod parts either, as they need to be almost PERFECTLY straight. (don't go too crazy making them super perfect though)
on the glass, apply pressure on both ends of the part until it forces the center straight.
Hi guys, back to you. I seem to have straightened/aligned most everything so that the unit turns freely on glass. I am getting it back together for track test. I probably will have to re-adjust everything in the Tsunami since the drag will be gone.
Now I have a different problem: the 2-wire inside plugs are identical with no special keying difference. They both electrically connect with the larger outside plug. Which plug does the motor harness plug into, fireman or engineer's side? I haven't found a darn wiring diagram and have forgotten which is what. I sure wish Bachmann would follow NMRA color code, but I know...they try to be universal.
BTW: this is a light mountain 4-8-2.
Disregard the last paragraph. I figured it out that the motor leads plug into the engineer side plug.
The track test looks clear of any jerking, but I haven't installed the outer shell yet. I will do that tomorrow and post the overall results.
Rex, it is entirely possible that much of your issue lies in the rods and gear, including the final drive (the tower). It may only be that your locomotive needs some generous breaking-in, as do the BLI steamers in my experience. Not a bad thing, just go slow, go often, forwards and backwards now and then, and lube before much more than an hour of break-in has passed.
I have found that newer locos take more voltage to butt-kick them down the tracks than will an older engine. So, once this engine works freely, and then begins to take more voltage, that will be a sign you need to perform some cleaning and re-lubing...I would think.
If this engine is already well worn-in, please disregard all after "Rex...".
Haha, thanks Crandell, but yeah it's an older one. It has always had some jerk to it and I can't stand to see a caboose hunching the next car . For some reason all my Bachmanns have done this (3) including my Shay. I had been using Tsnami's to adjust this out, but I wanted to get it out mechanically. so I decided to jump in and put my skills to the challenge.
Everything has pointed to the bad alignment of the rods and valve gear. The motor drive part is very smooth. After a lot of trail and error with the rods/etc., I now have it where it seems pretty darn smooth....for now .
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I now have created another problem. I can't seem to get the weighted inside to set flush with the bottom chasis. There is about a 1/16th" crack in the rear that won't allow me to put in the back screw. Haven't figured out what the heck is holding it up. The worm gear is mated, but something isn't right. Got any ideas?
Well, found one err. I didn't have the beltside worm gear bushing seated correctly holding the gear up a little. This helped to get the back screw in and everything seems to mate up with very little back clearance and it runs good. Dang...you sure have to be careful and it doesn't help not having anything but a blown parts picture. Now to put on its clothes and give her the final test run .
so I decided to jump in and put my skills to the challenge.