clutch gear

beentryin said:

its a problem im having!!!!!!

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The clutch design is such... A center hub (has the three studs sticking out) which slides over the shaft (this shaft drives the 10 tooth sprocket) and the pad holder (is the gear itself and holds clutch pads). Between the center hub and the pad holder if from what I understand are "57" small ball bearings. You can see these bearings by looking from the pad side. Look between the pad holder and the center hub. This unit shouldn't have any play to it except the gear itself needs to rotate around the hub rather smoothly. After this unit is slid over the shaft, which is keyed there is a 20mm or so nut that holds this total unit in place and secured, the flywheel slides over the three studs, and is both held in place and adjusted by the star nut. There is a small Phillips screw that keeps the star nut from rotating once adjustment is made. Does the gear itself move from the pad holder? If so this most likely can be repaired. I'd remove all the pads, lay the gear and housing on a flat surface, pins down, and use a stick wielder and tack in two or three spots ever so slightly. In doing so make sure the ground is on the gear itself so the current won't flow through the bearings.

beentryin,

Here's a series of animations that show how the clutch works.

http://motorbicycling.com/f30/animated-view-motorized-bicycle-clutch-assembly-8939.html

There is typically a little play in the gear...but like Al said; it shouldn't slop around.

Were there any small metal chunks in the case below the gear? If so...it may be what's left of the Chinese ball bearings.

I've had a few of these come apart. The ball bearings looked more like buckshot. Replace them with quality SKF bearings...and no more problem.

Jim

Creative Engineering said:

beentryin,

Here's a series of animations that show how the clutch works.

http://motorbicycling.com/f30/animated-view-motorized-bicycle-clutch-assembly-8939.html

There is typically a little play in the gear...but like Al said; it shouldn't slop around.

Were there any small metal chunks in the case below the gear? If so...it may be what's left of the Chinese ball bearings.

I've had a few of these come apart. The ball bearings looked more like buckshot. Replace them with quality SKF bearings...and no more problem.

Jim

Click to expand...

Jim, that brings me to a question. Is there a way that the hub can be removed from the pad holder without watching 57 small balls roll all around the garage floor? ie..do you need to tap on the hub or what. I've never had to go that far. What about removing ALL the clutch pads, pack bearing grease into the bearings, clean up and replace the pads? Ever do that? I held the hub on mine and spun the gear, and for the life of me I can't figure out how this junk stays together....

beentryin said:

no there isnt no metal shavings in the bottom of the case,but there is play in the ring gear.its like its loose.

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OK, I just went to the garage to look at a clutch assembly....

The clutch itself is basically made of 4 parts, not counting the hardware to secure it to the shaft.

1) Flywheel... this is closet to the engine
2) Ring gear..rotates around the hub. This is also the holder for the clutch pads.
3) Bearings between the flywheel and hub.
4) Pressure plate, has the three holes that fit over the hub.

If you have the complete clutch removed, and there is excessive play when you spin the ring gear (keeping the center housing secured), or when you move it perpendicular to the rotational axis, then you have a bearing problem. There is NO WHERE else that can cause the ring gear to have excessive play. As far as replacing the bearings, I can't help at this moment. Also I don't but would like to know the diameter of the balls that would work well. A part number will suffice.

Al.Fisherman said:

Jim, that brings me to a question. Is there a way that the hub can be removed from the pad holder without watching 57 small balls roll all around the garage floor? ie..do you need to tap on the hub or what. I've never had to go that far. What about removing ALL the clutch pads, pack bearing grease into the bearings, clean up and replace the pads? Ever do that? I held the hub on mine and spun the gear, and for the life of me I can't figure out how this junk stays together....

Click to expand...

Al,

Many of the kits come with a puller. After removing the large nut and washer from the center of the clutch assembly, you will see that the hub is threaded internally. The puller threads into the hub. Make sure that you bottom out the puller or the threads will strip. The shaft and hub are on a slight taper...so it may be really tight!

The ring with the small bearings, 3mm, is a press fit onto the flywheel. To get it apart and replace the bearings; I hold the gear and tap the three pins until it comes apart.

It's a bit of a PITA to change the bearings. You have to be really carefull when pressing it back together...you have to make sure that the ring with bearings starts straight onto the flywheel while also making sure that the gear doesn't shift causing the bearings to dislodge. The ring is hardened, and was not properly annealed...Very brittle!

Jim

Creative Engineering said:

Al,

Many of the kits come with a puller. After removing the large nut and washer from the center of the clutch assembly, you will see that the hub is threaded internally. The puller threads into the hub. Make sure that you bottom out the puller or the threads will strip. The shaft and hub are on a slight taper...so it may be really tight!

The ring with the small bearings, 3mm, is a press fit onto the flywheel. To get it apart and replace the bearings; I hold the gear and tap the three pins until it comes apart.

It's a bit of a PITA to change the bearings. You have to be really carefull when pressing it back together...you have to make sure that the ring with bearings starts straight onto the flywheel while also making sure that the gear doesn't shift causing the bearings to dislodge. The ring is hardened, and was not properly annealed...Very brittle!

Jim

Click to expand...

Thanks, I have taken the clutch off the shaft but never the center hub and flywheel apart. 3mm good to know.