bummer - cush hub buffers - failed and missing - ???

wrapped everything up yesterday for the nortona event, and at the last minute everything went south. I took the 74 out for a final shakedown - everything seemed perfect, and a couple blocks from the house, I'm getting this, one per rev [rear wheel], metal to metal, banging sound. fairly sure it's the cush hub buffers. best I can tell, all three are missing. everything seemed fine the day before. is this something that just happens, or should I be looking elsewhere? with the bike on the center stand, neutral, and rocking the rear wheel assembly, it appears that these things not only failed, they're missing. seems like a simple enough job, just don't have the parts.

joe czech said:

wrapped everything up yesterday for the nortona event, and at the last minute everything went south. I took the 74 out for a final shakedown - everything seemed perfect, and a couple blocks from the house, I'm getting this, one per rev [rear wheel], metal to metal, banging sound. fairly sure it's the cush hub buffers. best I can tell, all three are missing. everything seemed fine the day before. is this something that just happens, or should I be looking elsewhere? with the bike on the center stand, neutral, and rocking the rear wheel assembly, it appears that these things not only failed, they're missing. seems like a simple enough job, just don't have the parts.

Click to expand...

Are they actually missing ? Not just melted?

baz said:

Are they actually missing ? Not just melted?

Click to expand...

best I can tell, missing. aft looking forward into the hub assembly, and with the movement of the rear wheel, back and forth, it appears there's nothing there. really won't know until I take things apart though. just don't understand - yesterday, everything's fine, today, total failure. what's puzzling, all three....

They age, perish, turn to useless powder over time and use. But during this failure process they can still provide enough Cush to hide the decay. Then one day they don’t any more.

So no, it’s not a sudden failure. It’s a gradual decay, but one that can create a sudden realisation of the symptoms.

joe czech said:

best I can tell, missing. aft looking forward into the hub assembly, and with the movement of the rear wheel, back and forth, it appears there's nothing there. really won't know until I take things apart though. just don't understand - yesterday, everything's fine, today, total failure. what's puzzling, all three....

Click to expand...

Maybe the brake cable is adjusted too tight and overheated the hub?

baz said:

Maybe the brake cable is adjusted too tight and overheated the hub?

Click to expand...

first thing I checked. seems the rear brake was in proper adjustment.

I have one set on the shelf permanently, as Fast Eddie says they decay over time but appear to go real fast. When you fit the new ones your next issue will be getting the wheel back on .

I partially melted a set once upon a time. They began turning into a gooey substance.

I have just finished doing a bit of recommissioning to my 74 mk2a, my first Norton, I took out the rear wheel to fit a proper tyre in place of the perished TT100, and as I did so the smaller of the rear Cush rubbers turned to dust in front of me.

Had these turn into dust also. For cushes they are really hard plastic. Seems like a bad idea. I believe you can make home made ones out of your old motorcycle tires.

I used some old heavy conveyor belt from a bauxite conveyor for a while once. Worked very well too. It was somewhat more cushy feeling than the plastic ones and a little more resistant to heat. Still have a bunch and may go back to it one day.

Short term sidewall of an old tyre will do. In fact maybe last longer than the correct bits. You can see why they finally went to the MkIII
modern type of cush. Problem with the earlier ones is that they are too small and were just something to get the poor original owner
through warranty period.

someone , somewhere must have improvised as per jbruney on P.11

found two on website;


Re: cush drive buffers

850cmndo said:

I hate putting the rearend together with new buffers, even WITH lube.

Some rear wheel castings are tighter than others. I use a belt sander to trim the thick pads to suit the lugs so you don't have to fight with the Speedo gearbox/ spacer and axel assembly when trying to reinstall the wheel to the drum. Ensure you can do this at the side of the road if in case you do get a flat and need to change out or patch a tube. Also your pads will melt into chewing gum if you do not apply your rear brake while you tighten up your rear axel. Applying the brake centralizes the shoes to the Drum and prevents this from dragging and heating up the drum to the point of melting the new pads you just installed. After installation and assembly spin the rear wheel with your hand to insure nothing is dragging. Go for a drive and stop after a ½ mile using your front brake and put your hand on the drum. No heat = happy trails.

CNN


Re: cush drive buffers

Best solution I got is to snip out blocks form fiber re-enforced conveyor belt. I snip em to kinda snug friction fit in hole and on paddle dry as when I've lubed them seem they or the wheel falls out too easy for my fumble tolerance. Also check the paddle still nailed down and square. If they twist a bit they can chew pads a lot better.

Throw yourself at the ground and miss!

hobot, Jan 31, 2011

I believe Hobot used to cut up his own from old tires ...

It took me a couple of times to get them sized properly to hold whilst removing and installing the rear wheel. This stuff is tough with the reinforcement weave inside. Made for moving abrasive & rocky material... Far easier these days to just order new since support has returned.

I over did my rear brake just before maiden voyage with new madass rims, spokes axles etc. .... arrived into my driveway with big smile until I noticed what looked like spider web engulfing my beautiful rear wheel, was the cush rubbers melted took longer to clean than to get new set from BritCycle delivered .... very humbling day it was .... yes Hobot believed he actually got better service life out of the old truck tires he cut up

I have a Commando rear wheel on my N15, and cut out the bottom of the bumper recesses, so that I can install them from the outside. I always carry spares when traveling.
No fun when they 'disappear' when far away from home.
Plus it makes wheel installing so much easier.. :

Madass140 has a modern cush drive hub conversion. Bit pricey, but would solve these issues.

Took my rear wheel off today and had a look-see at the cush rubbers. Think I need new ones?

How long have they been in service?