Inspection Threshold for Steering Head Welds, Axles, Etc.?

 Today I ran out of paved road and was forced to ride on gravel for about 3
miles.  The gravel road had periodic lateral bumps in it ... don't know why
those develop, but they do.  It really was an awful ride.  Everything on the
bike was rattling.  I'm lucky to have my teeth.

Just because I'm new at this ...

a)How much abuse do you have to put a bike through before you might provoke
structural issues?  (I mean, is my situation enough, or running over a curb
at full speed to avoid an accident, or stunting, etc.?)

b)As a motorcycle ages (mine has 18,700 miles on it now, Honda Shadow 600),
is there anything I'd be looking for?  Any best practices?

c)Has anyone ever seen or been aware of a motorcycle coming apart?  How old
was it?  Was there anything in the motorcycle's usage to provoke it?

Forgive me for being perhaps overcautious ... it is just that after I found
the freeway again I was doing 80 MPH ... I really would hate to have
something crack.

Thanks for all advice,
Datesfat

 wrote:

No big deal.


Don't worry about it.

A motorcycle chassis should withstand at least a 6~7 g bump without
deforming permanently. The suspension bottoms out at about 2 g's,
that's all the typical MC is sprung for.

Your Shadow is doing double duty with you on it though.


So strip all the paint off it and look for cracks. Use dye penetrant
or magnaflux to look for cracks.

I doubt if you'll find anything serious...


I read a story about how light weight, thin walled chrome moly tubing
Van Tech custom frames built for road racing in the 1960's started
breaking apart, but your typical street bike frame is NOT going to
break up, so you might as well forget about.

 Datesfat Chicks wrote:


I'm not a structural engineer but I'd guess that bike frames are
designed to withstand considerably more shock loads than 3 miles
of washboard gravel road.

Metal bent or stretched within its elastic limit returns to the original
shape when released. However, stress great enough to take it beyond that
causes plastic (ie, non recovering) deformation. Of course, it could be
bent back in the opposite direction enough to restore the original shape
at the cost of some crystalline damage ... if cycled often enough
then a cold-work fracture will occur (you can do this manually with
a paper clip).

If your concern were performance rather than structural failure there's
info on line such as the following:

http://users.metro2000.net/~cdc/magna/tech%20section%20and%20issues/frame%20strengthening/frame%20strengthening.htm


Ronald Reagan's ghost. He's the reason it's not a 750.


Some early Goldwing GL1800's had a welding fault which caused frame
breakage. This was a manufacturing defect, not a design flaw.
Also there were sub-frame failure issues with some Hayabusas.


It's time to let you in on a closely guarded secret. Code named
"Hirohito's Revenge". At noon on August 6, 2045 (the 100th anniversary
of Hiroshima), every Japanese motorcycle exported to the United States
will... [oops, 'scuse me for a sec, there are some men knocking at
the door dressed all in black with face masks like the Teenage Mutant
Turtles]

 

Realx...I sent them to help you with your grill and the shrubbery.
NEEE!

 Datesfat Chicks wrote:

Well, first of all, if your worrying about this, you are prolly heading
for a wreck.  You do know you can talk yourself into crashing, don't you?


I try not abuse anything I know, except for my tractor.  My trsctor will
out live anything I own, including me.


Air frames run millions of miles before they start stressing.  Unless you
bend a metal structure, your prolly good for 4.5 billion light years.



Yes, a Yamaha Twin Jet 100.  It came apart because we screwed with it so
much and jerry rigged it with bailing wire, it was just a matter of time.
I ended up burning both leggs on the pipes.


I would imagine if you went over a curb, then my statement for #1 above
could be true.  Check for bend wheels/rims and bulges in the tires.  If
the bike still runs fine, and your still worried, take it to a good Honda
dealer and tell them what happened and ask if the will check it out for
you.


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