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Broken front axel

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(@creaky)
Posts: 2
New Member
Topic starter
 

I was wondering if anyone has ever broken a front axle. My outfit is a Royal Enfield 2006 Classic 500 Bullet with a Cozy sidecar. I bought it secondhand about 18 months ago and have got it handling really well. It is quite underpowered with only a 535 big bore kit but I only cruise around at 75kmph max so that's ok. The other day I was taking a right hand corner (my chair is on the left) at about 45kmph and the front axle sheared straight through just where it enters the right fork clamp. The bike nearly threw me but I managed to pull up before any disaster happened. I have since replaced the axle and everything is ok, no other damage but I was wondering if the extra strain from pulling a sidecar would have anything to do with it. I had recently fitted a steering damper between the chair and the lower left fork leg which improved the handling greatly but of course made the steering heavy. No-one I have spoken to has ever heard of an axle breaking so I thought I would ask the question here. If you need any details here is the link to the RE forum I posted in. Richard, Australia.

http://www.enfieldmotorcycles.com/forum/index.php?topic=21656.0


 
Posted : May 11, 2015 1:03 am
(@al-olme)
Posts: 1711
Noble Member
 

I have NEVER heard any reports of broken front axles, sidecar or solo. Your axle must have been defective in manufacture.


 
Posted : May 11, 2015 6:28 am
(@Hack__n)
Posts: 4720
Famed Member
 

Probably a brittle part, incurred during the tempering process.

Lonnie


 
Posted : May 11, 2015 6:32 am
(@tinboatcapt)
Posts: 139
Estimable Member
 

I worked customer service for the US importer of RE's and Cozy's and in my time never heard of a broken front axle.
Jim


 
Posted : May 11, 2015 7:53 am
(@swampfox)
Posts: 1932
Moderator
 

Hack'n - 5/11/2015 11:32 AM

Probably a brittle part, incurred during the tempering process.

Lonnie

Maybe also some excess stress from improper torque of the axle retaining nut?


Lee
MB5+TW200+CRF250L+GTV300+INT650
XL883R w/Texas Ranger Sidecar
Zuma 50F + Burgman w/Texas Sidecar<Mrs. SwampFox

 
Posted : May 11, 2015 8:13 am
(@creaky)
Posts: 2
New Member
Topic starter
 

Thanks for the response. Swampfox could have a point because when I had the broken part (long end) in the vice I could not undo the nut. This holds the speedo drive on. It was so tight I used my map-gas burner and a finally a rattle gun to remove it. It was as if it had welded onto the thread. I'm glad no-one else has ever heard of this happening as I was a bit apprehensive when I took it for a test ride yesterday after spending all day fitting the chair and lining it up. It takes me 20 minutes to remove the sidecar and about 8 hours to get it back on and lined up. What I would like to do is make a turnbuckle arrangement for adjusting the mounts. Do you know of any such thing for the Cozy? In case you had not seen it this is the axle. I should have left the nut on for the photo but you can see the thread on the long section and it broke right at the end so there was no thread showing. (Long-winded I know but now you have all the facts) Richard

http://www.enfieldmotorcycles.com/forum/index.php?action=dlattach;topic=21656.0;attach=27704


 
Posted : May 11, 2015 12:28 pm
(@snakeoil)
Posts: 52
Trusted Member
 

All I can say is YIKES! I'd say you are pretty lucky not to have had bad things happen.

It looks like it broke at the end of the threaded section. I assume that the speedo drive goes inboard of the thread on the large portion which means that the thread was not over-torqued and caused the failure. It appears that it failed at the first thread. I'd say it was the result of the thread being cut with a sharp pointed tool instead of having a small radius on the end. The sharp Vee at the bottom of the thread creates a stress riser. It was probably improperly tempered as well so it had the right ingredients for failure. The nut probably came off hard because the thread was distorted from the failure and created major drag when you tried to unscrew the nut.

If you think about it, a thread in that area is a poor design. Granted many bikes have threads in the loaded portion of the axle. My Ural does as it threads into the fork leg on one side. But you won't find any modern, well engineered bikes with threaded axles in the loaded area.

Glad you came thru unscathed.

regards,
Rob


 
Posted : May 11, 2015 3:53 pm
(@peter-pan)
Posts: 2042
Noble Member
 

Front wheel coming off together with the middle part of the axis was reported to me in a sand pit jump from my best buddy in Germany many years ago with a Yamaha XT550.
But that thing had to take MANY abuses for years before Torsten bought it.

Broken drum break base in the back from a Takasaki Chineese messenger bike a few years back. Eduardo was just happy the bus driver could evade him, but not the bike...
Happened about in 2007 here in Costa Rica("comprese una "vacasaki"" / "buy a cow-saki" appeared on the black board a few weeks later at a clients company...good laugh)

Broken motorcycle frame from a chineese messenger bike I saw last Oktober...front with steering head on one side of the road. back and engine on the other side and the tank somewhere far...

Enfield is Indian and I have had some interesting "Aha"-moments during my years as service technician for machinery importers... So some producers mistake in conjunction with some users abuse (as You say the impact wrench on a frozen nut) is a good reason for a "throw out - put new" action.

In 1994 I myself went straight heading onto a bus while I had the steering of my wife's Toyota Landcruiser (earlier then 1974 - 3 shift) turned for a 90 degree right turn.
The former owner a "gifted mechanics!!!" had put a 1/2" screw where a ball joint was supposed to be installed.
Poison and bile I spit for month about that gifted mechanics as we continued to find every day more "ingenious solutions"
(Gift in German = poison)
In resumee: "$#it happens"
Mainly when someone things he is superman and does not need to obey the laws of physics and the rules of sane engineering. (isn't that true Jim Tinboatcapt?)
Sven


 
Posted : May 12, 2015 3:44 am