Broken Axle

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Being a Norton lover can certainly be a humbleing experience. A couple of weeks ago while putting the rear hub of my long time project 72 Commando back together, my buddy Dan said he was a good deal less than impressed with the design of the Norton rear axle assembly & my choice of stainless parts. After humming the melody for Diamonds are Forever (Stainless is Forever) I fearlessly explained that Nortons have many faults but bustin axles warn't among 'em. Now I see this thread and realize I shoudaa kept my big fat mouth firmly closed . . .

Nortons are great tools for teaching humility.

Vintage Paul
 
Two Commandos in my experience. No axle problems with either one.

Bought a black/gold 750 new in '71. I rode that bike hard, my first bike, wore it out, never broke an axle but I did have the pressed brake hub cush stubs back out of the hub and into the brake shoes, locking up the rear wheel on the 101 here in Los Angeles. Brian Slark worked for Norton at that time and he sent me a new hub the very next day. The new hub's stubs were swaged into place.

After I wore the '71 out and after a few other marks, got my current black/gold '73 750. At some point I came across an 18" Atlas wheel and bought/installed it to get the better rubber available in that 18" size. The Atlas hub's three lug nuts certainly help take the load off the two piece axle's connection.

Good point about overtightening.
 
Anyone besides hobot have multiple failure experiences on the SAME bike?
 
grandpaul said:
Anyone besides hobot have multiple failure experiences on the SAME bike?

I think we know that answer. :mrgreen:

But seriously, he probably has more miles (in, ahem, questionable terrain) than than anyone save perhaps comnoz.
 
Why not show the broken spindle to a metallurgist or experienced maintenance engineer, there's a good chance they'll know exactly why it failed.

Cash
 
Anyone besides hobot have multiple failure experiences on the SAME bike?

Dear Paul, the hobot had two axles break on two separate different Comabts not two axles in same Combat. When I asked Wes for the first time about his axle and he said oh sure it went 20 yr ago, it hit me that they really are made of fissionable material or design. Ms Peel is made to tear her stuff up but not mere factory Trixie I never treated harshly as can be so sweet I figure she may be my last C'do after I crash and part Ms Peel out.

I have no doubts the fracture develop over time, might start with a nick that happen to line up with a weak metal microscopic grain fault that works its bad chemical and mechanical weakening across till only a last straw breaks its back.
I believe many rod bolt failure work the same way, not really over loading them but small fault like a horse shoe nail...

If ya bored here's the time line that got Peel's, first off she was/is famous test hot rod in region that she was sold in so who knows that history, 2nd was '99 avator shot the folded tire twisted swing arm and shot us under power to ground from straight vertical, 5 yr later on accidental super power, learned to do 3 more faster way around than MX bikes in ruts or racers on banks, these other more furious phases all involve hi torque hits on smashed down patch to sideways wheelis or low side crash into hi side leaps to land on smashed down patch to really take a torque hook up hit, then pretty good amount of off road leaps and hits limbs, stumps, rocks anything she'd go over under power assist and some learning curve bad landings, then '04 loaded cargo for two and then some to Ohio, then on return showing off to sports rider saying he'd never seen one, when light changed I let Peel leap a wheelie across whole intersection then some mile later on cement heaved patched seams going 90 mph standing full upright, my always dragging a mile behind slow poke Wesley flashed past me at like 110 mph to wave me over, when stopped he just pointed behind me to see a 1/2 mile combat thick smoke screen d/t fender and swing arm almost rubbing completely though tire. Almost impossible to get going again w/o almost being bucked off until over 5 mph then settle down to low air tire like handling.
At the rally before I could leave we found that the drum bearing had come apart so DynoDave stolen a functional old one from a bike but it had not grease in it so tired thick oil before I left but likely that helped do in Peels.

None of these factors was present in Trixie which was fairly low mileage New Orleans city rider only until my time with her. Be pensive and I now highly reccomend similar to my rescue kit same as wise one wear a brake lever safety spring but hardly ever never need them but once in life time or two.
 
Knocked the rest of the teeth out of rear drum to pay some more to ride with Bikes Blues BBQ festival just around the corner in nice fall like conditions minus the colors yet. Double row bearing heated out oil, ruined to replace again.

Remains of 4 layer fiber enforced rock conveyor belt turned to chewing gum with cob webs, I assume from the lose beating slack 60 miles home.
Broken Axle

Broken Axle


The low RH paddle is tweaked/twisted away from center to fix.
Broken Axle


Circlip was out of its groove and stuck to the washer, groove still intact.
Broken Axle


http://rides.webshots.com/photo/2929338 ... 1179owdPPJ
Broken Axle


http://rides.webshots.com/photo/2659058 ... 1179hbQhss
Broken Axle
 
Hobot,

Just a long shot, I wonder if driving on one paddle could load up the sprocket bearing, is this why the circlip popped, and cause a fatigue fracture of the relatively weaker spindle?

Cash
 
Nope, Trixie rear end was redone in '07 after the deer strike and the paddles were all fixed aimed to center so what ya see is damage from either the initial break or the 60 miles ride back on it. I've welded and ground back pegs on 2 drums prior so rather aware of that fault. I've smashed up fibre enforced cushions before too but not melted em to mush with fibers randomized into a felt pad on top. The only partial cushions you can still see are the factory ones on the brake loaded side. I'd checked for heat of brake drag or bearing on/off prior to find it warmish normal. So only took pulling the fractured axle pin to set off the rest of the grenade. When I saw the circlip came out stuck to the washer I though for sure I'd need a new drum so I assume the end of axle tipping out popped the circlip to. Regardless the double row bearing was still frimly seated and took a a dozen good smack cold to drive it out so it leap a few yard on last bop. Radioactive material with a half life of random fission lurks in all our factory steeds. I'm trying to eliminate all risk of my ridding hobby that I can control, axle safety clamp is now on that list. Have lightening strike you twice and see how it affects your reasoning with hearing thunder or bearing down on lumpy corners.

How much am I steeped in what it takes to stay in Commando game, I can't remember the last time, years ago, I bothered getting a total on an order, just open right up and let it bleed out as needed or don't ride. Oh I save em all in a a big over stuffed loose leaf note book to let wife be shocked going through it went I don't make it back to it.
 
Jeepers Mr. Hobot!

Say it isn't so!

Just looking at the terribly neglected, unlubed condition of your rear chain makes one assume perhaps a lot of your problems are perhaps self inflicted?

No personal offense intended, just an observation. I sure you will have a good response to prove my assumption unfounded!
 
My first reaction is to slap you silly, but refrain as can't reach ya from here. Get this straight though I live/ride in desert grit conditions both on my cycles and my mower chains, and as proven for eons those who run in sandy gritty conditions, get less chain wear and heat friction by running plain chain dry as a bone or X-ring sealed chain that's only dry brushed dusted if I'm bored between real issues to deal with. If you ain't running the factory oiler set to make whole back side wet and grimy, or not removing chain to flush by hot boil in paraffin/diesel then dunked in melted graphite grease, then you ain't yet up to speed on the facts of chain matters.

One event stands out a few weeks prior to parking lot fracture, came out a blind sweeper under power going 70ish to have a brick size-shape rock directly in path so hit it dead on square than rish a glancing blow trying to avoid it. Its a silly reflex I had imprinted on me d/t Gravel Travel. Not as bad armadillo speed bumps though, but worse than house cats and rabbits.

Another event might have weakened axle in '08 when logging trailer ran me into shallow ditch side at 30ish mph and was doing fine kinda riding it skewed like a lazy flat tracker taking my time to over take log truck and get back to grade when over the crest appears a wall of brand new debrie form road grader, which was now coming back piling up a berm and closing gap with log truck, so freaked out with nothing to loose so nailed throttle got sideways in now 3 ft deep ditch wall till hi side snapped Trixie and me back to grade to leap berm to land 45ish degrees sideways to path and grader blade so let her kinda crash and wobble diagonally past front of the grader, to see appearing through the blinding dust clouds two cars trying to over take the grader so no relief but to nail in some more and squirt between the cars and grader to get to clear air path again. Noticed a flat tire sense but only turned out i'd twisted swing arm so much I'd popped apart the RH lower shock mount swinging in the breeze. Best safe way to test hinged handling besides a blow out is remove one shock.

Oh shoot what really likely did it was comming home after dark 3 wks owning Tirixie and deer leaped into head light to flip bike so hard sideways in air out from under me the front tire beat had deer fur jammed in all the way around, bike apparently twisted in air and landed sideways with rear leading then bounced again and landed on my L knee still sliding out stretched so only skin held it on discovered by lifting thigh while rest of leg stayed on ground till it bunggee corded back into place which knocked me down again.

So hey all in all us dumb axle things can take a lot before they let go.
 
When I changed the axles on my 73 850 they had 55,000 miles on them of long distance (road) use mostly freeway trips between Los Angelos & San Francisco from what I have learned. The rear one was well worn and thined in areas so I replaced it but I'm sure if it had been put thru hard race track use or ridden in off road conditions that stressed it like going over stumps and small jumps it wouldn't have lasted 55 K miles. I am not suprized "the Hobot" broke two,,, I'm suprized he broke ONLY two.....
 
Hehe hobot can take your hurtful humoring, as I thought the same way for about 6 yrs reading of broken axles yearly on more ancient lists than this, before I came to know they were just plain radioactive. Even in nuclear reactors and bombs a certain percentage of atoms remain to fission dangerously later. So reports of long lasting axles is no proof at all yours won't pop next meek ride out. As novice as I am I have long list of world wide vendors that go "Oh Hello Easy Money" at my name,so will go down that list again and ask how many Norton axles they tend to sell, just like how many hundreds of dead AMC gear boxes are their in piles around the planet waiting to be melted down as unrepairable. Best wishes I'm the last abusing teenager to pop an axle for ever more eh. Meantime I'm going to install a dead rabbit foot for luck in the form of Jubilee clamp and safety wire back there. How absurd is that?
 
I had the same problem and it was one small spacer missing... check the parts diagram and verify that all the parts are there. Cheers Robin
 
Hey Hobot I didn't mean to insult you in fun or any other way I was just saying I think the fact that you not only ride hard but you also do it on some pretty harsh terrain. I left a friends house a while back & since the driveway was blocked I road down the sidewalk to the next driveway but I was going a bit to fast & ended up jumping the end of it, no problem for my front end but I thought about how the rear axle isn't really meant to take that abuse. I've had it out & all is well but I do baby it a bit.
 
Yep see what I mean, a sudden jar can happen to anyone and they accumulate just like radiation does in tissue genetics, never knowing when the last straw snaps it. So if you'd of nailed the C'do as you leaped off the lip you'd of lessened the angle of the axle shocking.

I've an un-earned devil may dare reputation, further proof of this will be a safety clamp on my 750 axle as more often needed by far than the brake lever spring. I ordered new felt sealers but everything in parts books showed up on dismantling. I am not one bit offended to be chided to make sure Its all there even if I ain't. Yoose guys that don't run the rough stuff don't realize that there is a certain speed threshold I call planing speed where THE Gravel kind of smooths out - as one local teen rider told me- tires skips over some of the bumps instead of hitting them all.

Drum had one paddle twisted and another found loose wiggley, so took drum to a Ozark mechanic that works out his PU but keeps a welder in home so got em done for correction and prevention. This is 3rd or 4th drum I've had to do it on.

Broken Axle

Broken Axle
 
Would anyone berate Speed McQueen testing his Triumph axles or not being a model for safety gear?

Broken Axle
 
Hey Steve, yer "bad C'do luck" never ceases to amaze me. Hope to learn from yer sufferings and not go thru them myself. :shock: I just bought a "fleabay" Honda CB350 17mm rear axle myself. As getting paranoid per all the recommendations on the forum. So, are you going the 17mm one piece axle route, or some other path ... ???
 
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