Anyone experiencing binding worm gears?

[sh996]

I picked up my micro crawler Wednesday and took it home to try it out. Fresh out of the box, fully charged battery, and it seems to have either binding in the worm gears or the tranny. It runs very loudly and on the initial start it takes almost 1/2 throttle to get it moving. Once going, I can slow to a crawl and pick up speed again. But if I stop completely, it again takes almost 1/2 throttle to get it moving again. This is on carpet in the house. When trying to climb any obstacles from a stop, it binds up and won't even climb. This is pretty frustrating.

To give a little background, I have the mini crawler and the 1/10 crawler, I know all about the worm gears and initial troubles Losi had with the 1/10 initially (still have it, love it, compete with it frequently).

I haven't seen or heard of anyone else having these troubles, I'm hoping I just got a bad one. Anyone with any guidance or similiar experiences please post up. If I can't get it running better by Monday I'll probably return it and maybe get another one, or maybe wait a little while for any bugs to get worked out of it then buy one from a later batch.

Thanks for the help!!

Keith

[shimey]

Just got mine. Runs really rough out of the box. Same sort of deal with initial throttle. I'm wondering if it's spur/pinion mesh and not worm gear....

Haven't had time to tear it down yet. Just running it. Maybe it'll break in a little.

[Ralphy]

Sorry to say that all 12 in our area are smooth running. wish i could help.

[TruckerBrad]

First thing I did was open up the transmission and the diffs and threw some grease in them. Mine runs quiet and smooth.

[shimey]

Just got into my transmission.

1. Spur/Pinion mesh was WAY off. The two sides of the slipper disk don't center the spur on the output. Messed with it for 10 minutes. I think it's a first run "problem?" Finally got it to about 90 percent by running the throttle with one hand and tightening the slipper with the other. Yeah, give it a try.

BUT my binding wasn't gone.


2. Pulled the tranny and found a pretty glaring problem. Tranny is DEFINITELY binding. From the factory. Turning the shafts by hand (finger) produces a grinding every rotation. When it's not grinding it's smooth as butta. Don't even have to "pinch" with my fingers to turn it. When it's bound it takes considerably more pressure to turn the shaft. I can't tell what it is. Output shaft doesn't look bent. Output shaft gear OOR? Spur gear OOR? Bad bearing? It's almost as if the seat for the bearing in the cover is MICRONS off. Goes away with the cover off. Comes back with cover on. EDIT: just flip-flopped the OS bearings: no change.

Wondering if Rich is perusing this thread? I'm going to try to get video. The grinding is pretty audible.

EDIT: VIDEO LINK: http://www.youtube.com/watch?v=-b3-KErVCyE

[JeepinOR]

There is another thread on these Micros that concerns a similar problem. I believe the thought was that the gears aren't truly "round."

EDIT: binding in the tranny

[J'aimesetrainer]

I have the same problem with mine aswell. Who knows. I had taken mine apart greased it and I still get clicking in the "pumpkin"

[sh996]

Thanks to everyone for all the replies, info, and link to the other thread. I haven't had a chance to do anything yet with mine, but I'll probably tear into it and see if it's the same binding going on (probably is from the sound of it).

Keith

[woodymaxx]

Went a head and tried to figure this problem out on mine as well with no luck. I found the problem gear, marked where it's binding and took a hobby knife between the teeth to try and clean it.. Nothing. Even try sanding it down a little with some 2000.. nothing. Then I ran it with the battery hooked to the motor and the crawler upside down threw a pack and still nothing! Hopefully losi will acknowledge this because the low speed driveabilty would be really nice to have.

[EKIM14]

I just tore into my tranny and I think the problem is not only in the gears but the tranny cover itself. The side with the 4 short screws in it that holds the 2 bearings for the gears. when I remove the cover completely the binding is minimal/gone. I spent an hour fiddling with the cover and I finally got it bolted up and no more binding. It sure makes slow speed crawling 10x better and im even getting lower temps because the motor doesn't have to fight the gearbox anymore.

I think it is the two indents in the cover where the bearings go that are the culprit. I cleaned them out with 400 sand paper and alot of cursing just enough to give the bearings less than a mm of room and it worked or me. A precise cnc tranny cover and round gears could be a huge upgrade for this little monster

I'm sure that the cleaning out the cover is masking the wobbly gears but it fixed the problem for now. At least I can tolerate this thing while I wait for a fix

[woodymaxx]

Hey great Idea!! I just ovaled my cover out too.. Just enough on each bearing.. smooth now! It actually crawls now! Got a couple of minutes more of run time out of it too!

[VooDuuChild]

Anyone got some pics of the sanding of the cover and where??? (sorry, I don't even have my crawler yet, should be in a day or two, but it'll be nice to know where to start!!) Gracias!

[username]

So Ill have to bust out my dremel and hit a few spots it sounds like tomorrow. that is my biggest beef right now is no low speed.

[EKIM14]

Originally Posted by username

So Ill have to bust out my dremel and hit a few spots it sounds like tomorrow. that is my biggest beef right now is no low speed.

Don't use a dremel. Definitely do it by hand. I put a bit of sandpaper on the tip of a screwdriver. It doesn't take much to make a huge difference. Go slow and test fit as you progress. you will be able to feel when its not binding anymore.

[username]

Originally Posted by EKIM14

Don't use a dremel. Definitely do it by hand. I put a bit of sandpaper on the tip of a screwdriver. It doesn't take much to make a huge difference. Go slow and test fit as you progress. you will be able to feel when its not binding anymore.

yeah, i realized that when i took it apart. but i removed just enough so the larger bearing can move away from the smaller one. thats what i was supposed to do?

[mOOsE]

Originally Posted by username

yeah, i realized that when i took it apart. but i removed just enough so the larger bearing can move away from the smaller one. thats what i was supposed to do?

yup. It allows the crap-gear mesh to move apart where it would normally bind from being too tight.

[Dingman]

That's what I had to do... clearance the plastic for the larger bearing, so that it could move away from the smaller. Just enough that I started to work about mesh.

It's almost gone now, but not quite, still a little. Way better tho.

[jonesy]

Originally Posted by shimey

2. Pulled the tranny and found a pretty glaring problem. Tranny is DEFINITELY binding. From the factory. Turning the shafts by hand (finger) produces a grinding every rotation. When it's not grinding it's smooth as butta. Don't even have to "pinch" with my fingers to turn it. When it's bound it takes considerably more pressure to turn the shaft. I can't tell what it is. Output shaft doesn't look bent. Output shaft gear OOR? Spur gear OOR? Bad bearing? It's almost as if the seat for the bearing in the cover is MICRONS off. Goes away with the cover off. Comes back with cover on. EDIT: just flip-flopped the OS bearings: no change.

Wondering if Rich is perusing this thread? I'm going to try to get video. The grinding is pretty audible.

EDIT: VIDEO LINK: http://www.youtube.com/watch?v=-b3-KErVCyE

i had this problem with my 1/18 MRC .... it was wierd as hell. pull the cover off, and nothing binds, put the cover on and it binds about every 1/3 turn.

i cleaned all the plastic shavings / chunks out of the cover and off the bearings and played with the cover by pinching it onto the trans with one hand while turning the outputs with the other.

i finally got it to stop binding and found out that, for mine at least, the order in which you tighten the screws affects the binding. i started with the screws furthest from the motor and alternated side to side with tightening, making the screw closest to the motor the last to be tightened (with exception of the single screw on the back of the housing).

dont know why, but with that combination of things and general luck, it runs very smooth now. i did add some grease to the trans gears as well, though i dont believe that was the cause for any binding.

[KnutKase]

Has anyone tried to enlarge the holes for the screws that hold the cover on? Instead of enlarging the hole that the bearing fits into try to re-align the cover thus changing the gear mesh to allow more room, but not allowing wobble.