differential gear backlash By scooterbob (Read 2,547 times)

[mike6736]

Well, have no idea what your riding,you did not say... If you have all that going on you better wait and not run it till the dealer gets back to you as you will make it worse.

Magoo

[Bashan]

Scooterbob, your posts are to the point and very clear. You have nothing to apologize for. It's nice to see posts that actually have punctuation and are not one long run on sentence. Now if you want to talk old.....we have Magoo on our roster. He's so old he farts dust, (just kidding Mike........just kidding.).

Let me get my OCD out of the way. A differential is an assembly of components that allows two shafts to rotate at different speeds off of the same input. The gears at the back of a scooter are called the final drive gears or reduction gears.

Are you sure it's the reduction gears? There's lots of things that can go "clunk" on a scooter. One is Magoo's head hitting the speedometer when he falls asleep in traffic, (KIDDING! JUST KIDDING!). The engine mount will clunk if the rubber bumpers are missing. The rear wheel will clunk if the retaining nut is loose. The clutch can sometimes make a clunk if it's about to fail. It's kind of a moot point since you're under warranty but knowledge is power.

Mike is so old when he was in school there was no history class.

[Alleyoop]

Scooterbob,
Is this a 50cc TRIKE from IB? If so check your wheels jack the whole back end up or on wheel at a time and grab the top of and bottom of the tire and see if you can rock in and out. If so your axle has moved out and the clunking is either the axles slipping inside the Differential gear sleeve and or the Hub is slipping on the end of the axles splines.

If axles moved out WHICH is very common, you need to get a hammer and hit the end of the axle and push it back in so the axle tightens up on the Gear Sleeves KEY.
Alleyoop

[Alleyoop]

Bob,
I really do not think its the gears in the differential It is an OPEN DIFFERENTIAL very simple been around for decades. Have you filled it with GREASE? There are 4 spider gears in the differential the ones that turn the axle have a sleeve with a BUILT IN KEY and the axle has groves that the KEY TIGHTENS into. But on the trikes the axle a lot of times moves out a little.
Here is your axle taken apart, the 50s and 150s use the same axle the only difference is that the 150s have 4 mounting brackets while the 50s only have two mounting brackets. So my axle on my 150 is the same as yours. I have had it since march of 2009 and have over 10000 miles on it.
Alleyoop

The sprocket turns the differential and the Two on the shaft are the ones that turn the gears that the axle locks onto on each side.

[olddog]

Aug 25, 2013 20:39:47 GMT -6 scooterbob said:

Hello Bashan: I wasn't always old. Once upon a time I built Drag racing cars and engines. That was my hobby for 12 years. At 16 years of age I started tearing everything I could apart and putting them back together. I set up my share of differential gears. The differential in my scooter is not propelled by a drive shaft, but by chain and sprocket. The scooter does not have a pinion gear and can not be adjusted to remove excessive clearance with the use of shims. The entire set of gears have to be replaced due to excessive clearance. The gears may not be tempered to the correct hardness to prevent premature wear. I need to add that my 1974 Chevy Nova ran 10.80's in the 1/4 mi. with a 355 C.I. Small block Chevy. No brag just fact. I know my mechanics. Scooterbob

Hey there!! That seems pretty impressive!! And I only understood half of what you wrote. Because ally and bashan and scooterbob are explaining all that stuff here I am actually beginning to understand about the relationships of possible knocking and mounts and differential/gears, etc.... (Although Magoo never hit his dash per se, did he??). So thanks for I am learning while y'all are solving...

[Alleyoop]

Good luck, let me know if you have any questions. There is some slop also due to the gears in the tranny so before everything meshs against each other you do have some play. You can lift one wheel up off the ground and turn the wheel a little before the gears and sprocket all mesh and grab ready to pull.
Alleyoop

[Alleyoop]

There really are no seals, just a rubber dust cover on the end of the axles. Sounds like the bearing on that side is shot, they are sealed by the way and no grease applied on the outside. The wheel bearings are 6205RS.
Alleyoop

www.vxb.com/page/bearings/PROD/kit7594?gclid=CPyetteEnLkCFctcMgodL04Amg

[Alleyoop]

HAHAHAHA, you wishfull thinker you, once you take the "C" clip out you will need a puller and pull the whole axle out then you will need a puller to take the Bearing off.
What I use is a hammer type puller I take the wheel off LEAVE THE HUB on screw the castle nut back on bolt the piece of the hammer puller to the Wheel studs on the HUB and BANG BANG BANG to get the axle out.
Then hook the fingers around the bearing and again BANG BANG BANG. To get the new bearin on you will need something that fits the inner ring of the bearing to bang it on. I used a pipe or you can use PVC pipe and I used a piece of wood to hit is square.
Alleyoop

[Alleyoop]

it does not take to much pounding on the hammer puller it may just pull put it depends how tight the bearing is fitting inside the axle tube.
You have to put the bearing on first then slip the axle in and find the KEY with the open slot on the axle. What I do is as I pull the axle out try not to rotate it and notice where one of the slots on the axle lines up to the axle tube so when you slip it back in you line it up again and will just about line up the slot with the key on the worm gear sleeve key. You will feel when the slot on the axle found the key then I push it in and give the end of the axle some light taps and you will hear a tunk sound that it is bottomed out.
Then put the spacer washer C clip and dust cover and then the HUB back on and mount your wheel.
Alleyoop

[adolphsson09]

I have a question I took my differential apart because really noisy and I found the shaft looks like flat in the picture and the gears are really sloppy I am pretty sure there shouldn't be a flat spot and the gears should fit better than they do Has anyone seen one like this The trike has 229 miles I believe the haft came like this from the factory and was sent anyway

[cyborg]

i take it these shafts are where the spider gears are located ,,

[adolphsson09]

Yes it is Not much to them

[richardv]

The flat area on the shaft may be to allow oil to get in between the shaft and the gear. I have seen that on old machines.

[adolphsson09]

Yes I took the differential to a friend of mine and he said the gears are die cast and that is possible that the flat spot is to allow lubrication to get in there but he did say the gears are a little to sloppy which may be why they are noisy especially the one side so he wants to try shims to see if that helps and possibly make a different shaft a hair bigger in diameter we will see if it helps if not I will be ordering a new differential

[Alleyoop]

The differentials are the simple open type which have been around for decades not much to them and work well on these inexpensive trikes.

Make sure you put enough grease in there and also get the highest temp grease otherwise it will turn to liquid due to the heat and come out. I have over 12000 miles on my differential and have no problems but I fill the differential with grease.
Alleyoop