Gruber
HobbyMasters
M.L. Toys
KidsWheels
Gruber
HobbyMasters
M.L. Toys
KidsWheels
HobbyMasters M.L. Toys
Gruber
KidsWheels
Anything you want to put here that is "G" rated that doesnt really fit anywhere else
By johnny1333
#59329
i was just given a gently used mx-350 dirt bike. lady said it ran fine, stored it for the winter and now it won't work. 1st thing i did was test the batteries, multimeter reads them at 24.0 volts. when everything is together, it won't move, the motor just makes a humming sound like it is trying to go. i then hooked the batteries straight to the motor, thinking it was a bad controller or throttle. same thing! should 2 12v batteries in series read 24.0 volts? i thought it should read around 25 or 26 volts. any help would be appreciated, even if it is a guess, this thing needs to be done by friday, as it is my sons b-day gift. thanks!
By johnny1333
#59330
also, i put them on the schumacher charger and each 1 was fully charged, as soon as i connected it, and turned it on, it went from charging to charged (red to green). on both batteries. i know the charger is good, i use it on other batteries. not sure what i am missing here. thanks!
User avatar
By DennisDaMenace
#59332
The batteries are most likely dead. The true test is to measure the voltage when you connect the batteries directly to the motor. If the voltage drops drastically from 24.0 volts, you will need to replace both batteries. In my experience, it is usually one of the two batteries that at is dead but you should always replace both batteries.
User avatar
By aVWguy
#59757
how free does the motor spin?
if it was stored in damp conditions there could be rust inside the motor causeing problems too
those motors arent hard to open and clean with carefull hands .. as many times as i've done it the only difficulty i have is getting the brushes back down on the stator
to open it there are most often screws on the sprocket/pully end that will release the cover on the opposite end (screws pass through the entire motor shell
takeing pictures of each following step takeing it appart helps get it back togather in the right order

clean EVERYTHING
the contacts where the brushes make contact clean up easily with a good big pencil eraser
the rest may need little more then a clean rag and some 3in1 oil to get clean
if there is bad rust a small toothbrush size wire brush takes care of it (the brass ones are nice)
once all is nice and shiney again look oil the bearings and reassemble with the pictures, patience and mabey some coffee to keep ya going


if you look at the plate that holds the brushes some have two tiny holesthat a small pin or nail will pass through with the brush pushed completely back into its holder

others fight a bit more and requirethe effort of all available fingers to hold them back into the holders and pass everything back into place

(brushes are small metalic looking blocks that rub on the armature in the back end of the motor)




this method also works with garden tractor starters and VW generators LOL
By johnny1333
#59760
aVWguy wrote:how free does the motor spin?
if it was stored in damp conditions there could be rust inside the motor causeing problems too
those motors arent hard to open and clean with carefull hands .. as many times as i've done it the only difficulty i have is getting the brushes back down on the stator
to open it there are most often screws on the sprocket/pully end that will release the cover on the opposite end (screws pass through the entire motor shell
takeing pictures of each following step takeing it appart helps get it back togather in the right order

clean EVERYTHING
the contacts where the brushes make contact clean up easily with a good big pencil eraser
the rest may need little more then a clean rag and some 3in1 oil to get clean
if there is bad rust a small toothbrush size wire brush takes care of it (the brass ones are nice)
once all is nice and shiney again look oil the bearings and reassemble with the pictures, patience and mabey some coffee to keep ya going


if you look at the plate that holds the brushes some have two tiny holesthat a small pin or nail will pass through with the brush pushed completely back into its holder

others fight a bit more and requirethe effort of all available fingers to hold them back into the holders and pass everything back into place

(brushes are small metalic looking blocks that rub on the armature in the back end of the motor)




this method also works with garden tractor starters and VW generators LOL


i'm wiring in the new batteries now, if that doesn't work, i'll be doing what you suggested. thanks
User avatar
By aVWguy
#59764
check and see how free the motor is before ya break it open though ... if it spins smooth and has no funny noises it might be ok ...
By johnny1333
#59770
wired it up to the new batteries, put it all back together and it works. that little thing is pretty fast too! hauls my butt around pretty good.
By johnny1333
#59786
aVWguy wrote:glad to hear it man
have a blast with it lol

lol, i'll be teaching my boy to ride it here soon, but thanks for all ur help, if i ever need to tear apart a motor, i'll be coming to you.
User avatar
By aVWguy
#59828
after the first one its easy lol
i started with starters and generators for old volkswagens and farm tractors
User avatar
By MomWithKidsWithToys
#147044
Hi, I know this is an old post. But I'm having similar problem and this thread is closest to my problem. If you have any feedback t would be greatly appreciated. Basically i have the pink version mx350 w 2 12volt batteries I got it used and the chain needs replaced cause it's rusted pretty bad. It sat outside. Well I charged it and it turns on and light is red I had the throttle and it makes a weird motor sound. I can figure if it's the batteries not good enough to make it go but it stays still. If I manually push it around forward the chain doesn't move. If I push it backwards it moves but as I stated it's rusted. I don't get a reaction in motion only sound when I throttle it. So how can I self diagnose which part to replace? Motor or batteries? I don't think it's the electric box due to the button coming on and noise I would think it's fine. And i know I need a chain. Any input? TIA so much cause i only paid 25 bucks but I just want my daughter to basically learn on it so it wasn't gonna be grand anyways. I was gonna paint rusted wheels and buy a chain so it's be perfect for something to just okay with until she gets a gas powered one.
User avatar
By toycrusher
#147147
You should see nearly 28v with a pair of fully charged batteries.
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