1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Melted my cush drive rubbers! :(

Discussion in 'Norton Commando Motorcycles (Classic)' started by MexicoMike, Jan 29, 2019.

  1. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Yeah - I pulled checked the bearing (I have the CNW 520 chain conversion which uses a larger single-piece sealed bearing which has a larger outer race OD than the OEM bearings). It seems OK BUT I am ordering a new one from CNW anyway. Oh...and a set of the OEM-type cushions.
     
    Last edited: Jan 31, 2019
  2. kerinorton

    kerinorton

    Joined:
    Feb 12, 2013
    I like Jim C's idea as well. I dont have access to those tyres but I could always approach the local bike shop. I have had my new black rubbers in for over 8 years now though. After trial and error with changing wheels I ended up grinding the 2 lumps off the back of the rubbers to make wheel changing easier. At first I got caught adjusting the rear brake too finely and having the drum heat up so I then raised my brake pedal as high as it would go then reset the cable adjustment. I dont get any brake drag now and adjustments are less often. Some might say the pedal is now too high. Well as a comparison, a car accelerator pedal is usually a lot lower than the brake pedal, and that causes no problems. Its what you get used to.
    Dereck
     
  3. Lineslinger

    Lineslinger VIP MEMBER

    Joined:
    Feb 26, 2017
    Not intentionally mounted that way but I thank you for the observation.
    To be clear, are you referring to the outermost washer/retainer with the four open slots/openings/cut outs shown in the photos?
    If so, do I flip it over and secure it the opposite direction?
    I used original disassembly photos as a reference when reassembling, so a bit puzzled.
    Just want to get it right. Thanks again.
     
    Last edited: Jan 31, 2019
  4. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    Look at the parts list diagram and it shows them as steps outward.
     
  5. Lineslinger

    Lineslinger VIP MEMBER

    Joined:
    Feb 26, 2017
    Yeah, I figured that out.
    I was asking because the link won’t open on my iPad and my main computer is on the fritz.
    12 degrees this morning, shop heater can’t keep up. I’ll bring manuals inside and figure it out, wait for a warmer day.

    EDIT:

    My granddaughter showed me how to open the link within the AN site.
    Aren’t grandkids great?
    I’ll address that glitch the next time the rear wheel is off.
    Thanks again for pointing it out L.A.B.
     
    Last edited: Feb 1, 2019
  6. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Received a new rear wheel bearing (brake drum side) and new set of cush rubbers from CNW yesterday via economy Fedex so only 4 days to me in San Miguel is pretty good! I'll be installing the cushes and the new bearing tomorrow...even though old bearing looks/feels fine. I will also (finally) change gearbox oil from gear oil to ATF. Been threatening to do that for several years but am REALLY going to do it this time. Old gear oil is draining as I type this! ;)
     
    Hortons Norton likes this.
  7. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    This is an interesting thread.

    I pulled my rear wheel (for other reasons) recently. Cush rubbers look fine. Been in since 2013. Not done millions of miles but had hard use inc track time. I don’t use the back brake much at all though.

    So, maybe heat has a far more damaging effect than shock on these rubbers?
     
  8. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    This problem never happened to me previously in 13 years of riding this Norton UNTIL I installed the rear set and tightened the brake adjuster for minimum travel. I have never paid any attention to this but, I am now wondering if the problem is that I adjusted the brake lever to minimum...and I mean MINIMUM...travel with the bike on the centerstand. Then, with the bike on the ground and me on it, does the normal suspension sag/movement of the swingarm tighten the cable? If so, riding 150 miles with the rear brake "on" would certainly explain how the hub got hot enough to melt the cushions. ;)

    I'm going to check this out later today by removing the shocks and levering the swingarm up/down with bike on center stand to see if that induces brake drag with the brake lever free play set as I had it.

    FWIW, although I have been calling them "cush 'rubbers'," I have found through research that they are made of polyurethane as are many good quality suspension bushings.
     
  9. CanukNortonNut

    CanukNortonNut

    Joined:
    Aug 8, 2005
    Whenever I make any adjustments, disassembly/assembly to the rear wheel including brake adjustments, I make it a habit to drive the first quarter mile up the road and stop. I take my glove off and feel the brake drum for any heat. If it is there it needs adjustment again to get it right or you will melt the pads in quick order.
    Cheers,
    Thomas
     
  10. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    All back together now and I was extremely careful setting the brake lever travel. There's a lot more travel than I prefer until the brake engages but I found that the shoes/drum are not well-matched at all and unless I provide that excess (IMO) travel, there is some rubbing of shoes/drum at some point in the revolution. This occurs despite locking the brakes before tightening the axles. Would be nice to get a good mating surface between the shoes/drum. :( Anybody have a good method to do that?

    Re installing the wheel onto the drum with the new, TIGHT, cush rubbers - I used two bar clamps at 180 degrees bearing on the wheel hub on the speedo-gear side and the sprocket on the other side. Pulled the wheel onto the drum very easily.

    Fresh Dexron IV now in the tranny. ;)
     
  11. 850commando

    850commando

    Joined:
    Nov 1, 2014
    probably the only way to get a good match is to have a brake shop grind the drum and pads...
     
  12. ashman

    ashman

    Joined:
    Jul 11, 2010
    The front brakes do all the hard work the rear brake only slows the rear wheel down it also helps to have a good brake set up on the front.
    Another thing to look out for is the sprocket bearing mount where the circlip mounts on my Norton the outer circlip mount broke away and there was only about 25mm holding the circlip it made the drum grind on the brake shoe plate, I was only a few miles from home when this happened and by the time I got home the crush rubbers were completely melted away, something to look out for when doing maintenance on you rear wheel.

    Ashley
     
  13. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    thanks Ashman , I can add another worry to the list ;)
     
  14. alan hodge

    alan hodge

    Joined:
    Oct 10, 2017
    here's how I 'arched' the shoes/drum on the front/rear of my 72 Triumph T120 OIF/rear of 75 XS650 Yamaha/front and rear of '68 BSA A65 and rear of my commando.......glue strips of sandpaper to the inside of the drum....insert backing plate/wheel...put the axle in...put axle in vise....turn wheel whilst gently pulling brake lever on backing plate with hand...this will allow sandpaper to remove high spots on shoes …..dig?
     
  15. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Hmmm...I might try that, thanks!
     
  16. ashman

    ashman

    Joined:
    Jul 11, 2010
    This was not the orginal rear drum and sprocket but where ever my local shop get there parts from, it was a cast iron drum proberly made in India, I ordered a new drum from RGM but I was able to put the drum on a lathe and machine the circlip mount deeper and put a larger circlip in, still working good after 7 years and I have a new one sitting under my workshop bench which is steel not cast iron.

    Ashley
     
  17. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Thinking I might pull the rear apart again, glue sandpaper to the drum as Alan suggested, put it back together, put bike on center stand and run bike/lightly apply rear brake until shoes are "round." Then take it apart, remove sandpaper and put it back together! Whew!

    I know some folks view the back brake as an unnecessary item but I use it quite a bit and always have. I find it's great for tightening turns at low speed - parking lots/lane splitting and also for doing the same on the road. I can scrub off some speed/tighten a turn mid-corner without upsetting the bike whereas using the front brake will. Yeah...you can tell me I should learn to better judge my corner entry speed but that train left the station many years ago! ;)
     
    Nater_Potater likes this.
  18. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    Don't feel bad about using the rear brake... I use it also. Always have. It's not there for an auxiliary footrest anyway....Strange part is I can't really explain what I do with it, but I do notice using it...more of an automatic act which is applied with discretion. Noticed more so upon the discovery of this wassell master cylinder having the unheard of ability to lock my caliper, which was somewhat of a shock since the Lockheed couldn't.
    Besides Mike when you're the one humping the dog it's your call as to how it's done.
     
  19. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    DogT , I think came up with the sandpaper and glue for rear drum , not positive but I believe he rode around like that to get a good meeting of shoe and drum , maybe he will see this and enlighten me , was a few years ago .... I have always used rear brakes on all my bikes , like everything , seems to work better the more regular it used ....
     
  20. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Might be worth checking how the rear brake cable runs to the lever. If not properly routed across Z-plate and silencer mounts, cable tension and therefore brakes can be applied when swing arm moves.
     

Share This Page