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Message started by Boogieman on 06/29/13 at 17:40:37

Title: wobbly rear sprocket
Post by Boogieman on 06/29/13 at 17:40:37

ya so whatever u call that thing that the belt goes over at the rear tire has some pretty substantial play.
normal? or time for new bearings?

Title: Re: wobbly rear sprocket
Post by Serowbot on 06/29/13 at 18:20:43

Normal...

Title: Re: wobbly rear sprocket
Post by Boogieman on 06/29/13 at 20:01:52

Thanx Serowbot

Title: Re: wobbly rear sprocket
Post by Serowbot on 06/29/13 at 20:48:40

Welcome... :-?...

Title: Re: wobbly rear sprocket
Post by markbacon on 06/30/13 at 17:41:51

Normal, but not good. When the bike's new, the pulley's kept running straight by being squashed up against the cush drive rubbers between it and the hub. Once they wear it flops around a lot. You could live with it, replace the rubbers, or fit a wider double row bearing and turn down the spacer to suit (must be a fully sealed bearing 'cos you'd be ditching the standard separate seal).

You'd be looking for bearing with internal diameter 25mm, external 62mm, and thickness 24-26mm. E.g. NSK 5305DDU.

Title: Re: wobbly rear sprocket
Post by Dave on 07/01/13 at 03:41:07

Well I guess it matters what you mean by "wobbly".

If you have a bit of rotational movement of the sprocket....that is normal as the cushion drive does allow a bit of rotational "slop".

If you can tilt the sprocket out of being square and have a lot of movement that would allow the sprocket to "wobble"....that is not good.

You could try a new set of rubbers. Way back in 1974 I worked at a Suzuki dealer and the TM motorcross bikes has a cushion hub. The head mechanic had us take the cushion drive off, clean the parts, then mix an epoxy rubber and pour it in and assemble the drive back together and it would take the slack out of the hub. It would still allow the cushion to work - but removed the play. You could probably do a similar fix with silicone rubber.

Title: Re: wobbly rear sprocket
Post by justin_o_guy2 on 07/01/13 at 06:02:48

or, as i posted in another thread, slices of inner tube.

Title: Re: wobbly rear sprocket
Post by WD on 07/01/13 at 06:53:22

Gasket maker, use one that stays flexible. The rubber cushion drive blocks do tend to shrink as they age, take up the slack with rtv. Or you can use a silicon caulk if you prefer, get one designed for repairing semi trailers.

Title: Re: wobbly rear sprocket
Post by Boogieman on 07/01/13 at 14:17:13

"there are rubber triangles built into the hub to absorb power pulses & clutch engagement shock. they arent perfect. i sliced up an inner tube & shimmed them up. that decreased the amount of deflection the pulley goes thru under acceleration, decreasing belt wandering,m

contact cement is your friend,

pieces of inner tube cut too big, partially inserted on each of the long sides of the v shaped rubber will drag down into place when the v is pressed down, IF you smooth things up on the wheel 7 slime it with some glue.then trim to fit after its dried. i didnt mess with the outter edge, just the sides of the wedge.

this is a good time to decrrease brake shoe contact area so it doesnt lock up at the thot of using the rear brake".
I got it JOG i just don't have any idea what yall are talking about. probably time for me to get a clymers. Being a broke artist sucks!
Dave, its not rotational slop, It's the bad slop.
The only thing I can see or feel that is rubber next to the sprocket/pully is a rubber piece that seems to be in between the pully and the rear hub. Is there like a diagram somewhere on this site of the rear assembly? because y'all are given me key advice here, but since I've never been through it and can only see this nonsense from the outside I'm having a hard time understanding what yall are telling me.

Title: Re: wobbly rear sprocket
Post by Dave on 07/01/13 at 15:38:18

Whenever you need to see how something is arranged....go to any online parts retailer and look at the parts diagram. You can do it without out help!

Part number (4) is the rubber cushions:

http://www.hondaofflorence.com/fiche_section_detail.asp?section=432158&category=Motorcycles&make=SUZUKI&year=2005&fveh=10118

Title: Re: wobbly rear sprocket
Post by Boogieman on 07/01/13 at 16:10:13

oh sweet thnx

Title: Re: wobbly rear sprocket
Post by Boogieman on 07/01/13 at 21:43:18

#4 part number 64651-31001 shock absorber, hub?
Not #15 or #16... but #4. that weird a*s triangle shaped thing?
that sucker is really buried in there isn't it..

Title: Re: wobbly rear sprocket
Post by WD on 07/01/13 at 22:04:08

Yep, number 4 is the wear item in the cushioned drive hub. If you've damaged parts 15 or 16... somebody set your drive belt entirely too tight (and really overtightened the axle nut). And will likely have damaged at least the seal behind the front (drive) pulley (rear is the driven pulley). Fixable, but a major league migraine to deal with. The front seal, 15 and 16 aren't too hard to change out.

Title: Re: wobbly rear sprocket
Post by HighME32 on 12/14/14 at 17:05:09

So my rear sprocket actually has a bit of side to side play. I just reinstalled the pulley spacer because the shop that replaced my tire or my cousin's mechanic forgot to put it back on and it shredded mu rear bearings. I have the rear axle torqued to 50ft lbs. Should i replace the rubber triangles?

Title: Re: wobbly rear sprocket
Post by HighME32 on 12/14/14 at 17:07:19

BTW. I also have the belt loosened a bit because i have the ryca cs1 kit on. ...or should I just torque it up a bit to maybe 60

Title: Re: wobbly rear sprocket
Post by Dave on 12/15/14 at 03:51:07

Don't put any more torque on the axle that is recommended.....it will not do anything to reduce the wobble. Once the axle is tight and all the play is taken out of the spacers and bearings.....more torque won't change the clearances any.

Since this thread was posted I have learned a lot about the rear hub design. Unfortunately the only thing that is keeping the rear hub in alignment is the ball bearing in the pulley hub. When new the bearing doesn't allow much wobble - but the bearing quickly wears and begins to have play and allow the wobble. A new pulley hub bearing will reduce the amount of wobble for a while - but it will come back before too long.

The easiest fix is to cut some rubber carpet runner, floor mat or mud flap and install it between the rubber cushions and pulley hub. You can put a dab of silicone on them to hold them in place during assembly.
http://i60.tinypic.com/jpdj4k.jpg

As I got more involved in this, I discovered that the pulley hub does slide into the wheel hub - but for some reason the parts are loose fitting and it does not provide any support. I machined a bushing from brass so that the fit is closer, and it eliminates the pulley wobble entirely.
http://i57.tinypic.com/2yxfy8m.jpg
http://i60.tinypic.com/mmwf2p.jpg

I have been riding on this modified hub for a year now, and it works fine. If you have access to a lathe (or someone that does), this is a good fix.

Title: Re: wobbly rear sprocket
Post by pgambr on 12/15/14 at 04:21:52

I did Dave's mod with the hardened rubber over the spacer pads and it helped significantly. 8-)

Title: Re: wobbly rear sprocket
Post by HighME32 on 12/15/14 at 10:17:35

Nice Fix Dave! Yeah I have no machining equipment and a tiny bit of experience machining. I did just change the sprocket bearing and rubber seal, but noticed the play after. I retorqued it to 55 fr lbs which is still far from the end limit, as the troque specs for rear axle is 40-65, and you are right it didnt do much. What i did notice though is that when i sat on the bike and checked for play, it was gone. I think the looser belt tension from ryca belt adjustment contributed to the play. Another thing I noticed were some rough edges and one small dent 2mm dent on the part that you moded with brass. I filed the end off to make it smooth again and checked it with the old bearing. The inner bearing race still sat flush top of it.

Title: Re: wobbly rear sprocket
Post by Dave on 12/15/14 at 10:37:45

HighME32

When you did not have the metal spacer in the pulley hub, it then allowed the axle nut to pull the pulley hub up against the wheel hub, and it would not allow any play. Unfortunately the inner wheel bearing was not properly supported had side loads it was not designed to resist - so the bearing failed. There are numerous marks on your wheel and pulley hubs from them banging against each other.

And yes, the wobble appears to be gone when you sit on the bike, as the tension is increased in the belt. The pulley and pulley hub are pulled forward. The play is not gone however...the pulley is just pulled forward. With each rotation of the wheel, the pulley and pulley hub are moving in relation to each other so that the pulley is always leaning forward.....and this shouldn't happen. Put some rubber shims in there to reduce the amount of wobble....you want it gone!

Title: Re: wobbly rear sprocket
Post by HighME32 on 12/15/14 at 12:07:25

What's the thickness you used for the runner Dave?

Title: Re: wobbly rear sprocket
Post by HighME32 on 12/15/14 at 12:09:26

How much do you think a maschine shop would charge for a brass shim like that? What are the specs?

Title: Re: wobbly rear sprocket
Post by Boogieman on 12/15/14 at 17:50:03

I didn't end up replacing the rubber triangles I ended up cutting up pieces of old tire tube and stuffing it in there and there's no play at all now

Title: Re: wobbly rear sprocket
Post by HighME32 on 12/16/14 at 19:45:49

Dave, do you think vinyl runners would do the trick?

Title: Re: wobbly rear sprocket
Post by Dave on 12/17/14 at 03:28:36

I measured the floor runner that I used. It is 2mm thick....about 1/16", or as another has indicated an inner tube is similar.

I used the floor/carpet runner that you get by the foot from Lowe's or Home Depot,. It was leftover from what I bought to put on top of my file cabinets at work. It could be black vinyl...I really don't know what it is made from.

You just need something durable to take up some of the slack, and something that is a bit compressible. If it is not very rugged.....it will disintegrate and fall apart.

Title: Re: wobbly rear sprocket
Post by HighME32 on 12/22/14 at 17:43:53

What are the specs on your bushing Dave?

Title: Re: wobbly rear sprocket
Post by Dave on 12/22/14 at 17:54:25

12333D32171F69685A0 wrote:

What are the specs on your bushing Dave?

I have no idea....it is inside the rear wheel and all bolted together. I just machined a piece of brass to be a close fit to the hole in the wheel hub that the wheel bearing slides into.