The other day I ran my Honda Shadow through a ditch (going from Point A to
Point B using the shortest route), and it was kind of a jolt when the front
wheel started going up when it had been formerly going down (the bottom of
the ditch).

I'm sure it is all within design limits, but ... next time I have a few
screws undone ...

What is the right inspection procedure for the welds near the front of the
frame? (I'm assuming just look for cracks everywhere?)

Anything else I should know?

--
David T. Ashley (dta@e3ft.com)
http://www.e3ft.com (Consulting Home Page)
http://www.dtashley.com (Personal Home Page)
http://gpl.e3ft.com (GPL Publications and Projects)

On Jul 14, 7:42*am, "David T. Ashley" <d...@e3ft.com> wrote:
> The other day I ran my Honda Shadow through a ditch (going from Point A to
> Point B using the shortest route), and it was kind of a jolt when the front
> wheel started going up when it had been formerly going down (the bottom of
> the ditch).
>
> I'm sure it is all within design limits, but ... next time I have a few
> screws undone ...
>
> What is the right inspection procedure for the welds near the front of the
> frame? *(I'm assuming just look for cracks everywhere?)
>
> Anything else I should know?

In all likelyhood, your frame is fine.
I'd keep a close look at the fork seals though.

--
Rayvan

"Rayvan" <rvannuland@cachevision.com> wrote in message
news:c55363c1-0ae6-4027-869e-06d51c8b4638@25g2000hsx.googlegroups.com...
On Jul 14, 7:42 am, "David T. Ashley" <d...@e3ft.com> wrote:
> The other day I ran my Honda Shadow through a ditch (going from Point A to
> Point B using the shortest route), and it was kind of a jolt when the
> front
> wheel started going up when it had been formerly going down (the bottom of
> the ditch).
>
> I'm sure it is all within design limits, but ... next time I have a few
> screws undone ...
>
> What is the right inspection procedure for the welds near the front of the
> frame? (I'm assuming just look for cracks everywhere?)
>
> Anything else I should know?
>
>In all likelyhood, your frame is fine.

Thanks.

I'd tend to think the same thing. The reason is that during aggressive
braking if one hits a pothole, the forces would be far worse than what I
did. I've gotta believe that the frame is stressed for that, easily.

I'm believing that cracks in the welds would follow the familiar pattern:
an initial crack then propagation.

I'm open to any inspection techniques more sophisticated than "look
carefully for cracks". I don't want to get out dyes and UV lights, but if
there is any recommended technique or any warning signs I might overlook ...
I'd be open to learning them.

I actually have done a fair amount of riding through fields and so on with
the bike, but the stresses are very mild, much gentler than potholes. The
ditch is the first time I've really gone for a rough ride.

>I'd keep a close look at the fork seals though.

Could you let me know what I'm looking for? Oil leakage? Something else?
Thanks.

On Jul 14, 7:42�am, "David T. Ashley" <d...@e3ft.com> wrote:
> The other day I ran my Honda Shadow through a ditch (going from Point A to
> Point B using the shortest route), and it was kind of a jolt when the front
> wheel started going up when it had been formerly going down (the bottom of
> the ditch).

Ummm, how deep was this "ditch", anyway?

When I think of a ditch, I'm thinking of a long trench that is three
to six feet deep and two feet wide, and when you run your motorcyle
into it, you break your neck and die before anybody arrives on
scene...
>
> I'm sure it is all within design limits,

Yes, your steering head can easily survive a 7g bump without deforming
the structure permanently.

> What is the right inspection procedure for the welds near the front of the
> frame? �(I'm assuming just look for cracks everywhere?)

The welds are stronger than the steel they fuse together. Look for
kinked, deformed, dented, or bowed areas in the tubing near the
reinforcing gussets.
>
> Anything else I should know?

Your bike uses ball bearings in the steering head. If your excursion
dented the bearing races on the lower triple clamp, a ball bearing
will fall into the dent and the steering will feel "notchy" when you
turn the forks slightly from straight ahead.

Dented lower races must be replaced. Upper races don't carry the
weight of the motorcycle, so they don't dent.

"." <RhiannonX@gmail.com> wrote in message
news:1ec4a05b-7a5b-4618-9b68-54efad614ed9@k30g2000hse.googlegroups.com...
On Jul 14, 7:42?am, "David T. Ashley" <d...@e3ft.com> wrote:
> The other day I ran my Honda Shadow through a ditch (going from Point A to
> Point B using the shortest route), and it was kind of a jolt when the
> front
> wheel started going up when it had been formerly going down (the bottom of
> the ditch).
>
>Ummm, how deep was this "ditch", anyway?

Shallower than that. Maybe 2 feet deep and 15 feet across. "Ditch" may be
the wrong word. Anyway, it was very noticeable when I hit the bottom.

>When I think of a ditch, I'm thinking of a long trench that is three
>to six feet deep and two feet wide, and when you run your motorcyle
>into it, you break your neck and die before anybody arrives on
>scene...
>
> I'm sure it is all within design limits,
>
>Yes, your steering head can easily survive a 7g bump without deforming
>the structure permanently.
>
> What is the right inspection procedure for the welds near the front of the
> frame? (I'm assuming just look for cracks everywhere?)
>
>The welds are stronger than the steel they fuse together. Look for
>kinked, deformed, dented, or bowed areas in the tubing near the
>reinforcing gussets.

Thanks. That is the kind of advice I was looking for. I will look next
time it is convenient.

I'm sure everything is fine.

I only would have looked for cracks in the welds. I had no idea that the
kind of damage you mentioned would happen first.

> Anything else I should know?
>
>Your bike uses ball bearings in the steering head. If your excursion
>dented the bearing races on the lower triple clamp, a ball bearing
>will fall into the dent and the steering will feel "notchy" when you
>turn the forks slightly from straight ahead.
>
>Dented lower races must be replaced. Upper races don't carry the
>weight of the motorcycle, so they don't dent.

I'll check that out as well. Thanks. Again, I'm sure everything is fine.
Just want to have a look see.

Bike has nearly 10,000 miles on it (amazing). I haven't spilled it this
year (also amazing).

David T. Ashley <dta@e3ft.com> wrote:
> The other day I ran my Honda Shadow through a ditch (going from Point A to
> Point B using the shortest route), and it was kind of a jolt when the front
> wheel started going up when it had been formerly going down (the bottom of
> the ditch).

You do realize there's motorcycles built for going through terrain?
If you'd like to go cross country, might be worth trading your Shadow
against something a bit more appropriate ;-)

I've been told bits in suspension and steering are built so that when
they deform, they do it in a way to be immediately noticeable when
driving/riding. If it goes straight, doesn't vibrate and turns normally,
in all likelihood it'll be alright.

cu
.\\arc

"Marc Gerges" <marc.gerges@gmail.com> wrote in message
news:97fsk5-keb.ln1@pascal.gerges.lu...
> David T. Ashley <dta@e3ft.com> wrote:
>> The other day I ran my Honda Shadow through a ditch (going from Point A
>> to
>> Point B using the shortest route), and it was kind of a jolt when the
>> front
>> wheel started going up when it had been formerly going down (the bottom
>> of
>> the ditch).
>
> You do realize there's motorcycles built for going through terrain?
> If you'd like to go cross country, might be worth trading your Shadow
> against something a bit more appropriate ;-)
>
> I've been told bits in suspension and steering are built so that when
> they deform, they do it in a way to be immediately noticeable when
> driving/riding. If it goes straight, doesn't vibrate and turns normally,
> in all likelihood it'll be alright.

Thanks. The bike seems fine.

I will follow the other poster's advice and also take a peek at the items he
mentioned (deformation _near_ the weld).

The only thing that caught my attention is that the steering tube is awfully
short ... any forces at the wheel have a long lever arm to act.

On Jul 14, 1:00�pm, "David T. Ashley" <d...@e3ft.com> wrote:

> The only thing that caught my attention is that the steering tube is awfully
> short ... any forces at the wheel have a long lever arm to act.

The steel fork stanchion tubes are more likely to bend than the
steering head, especially if you run headlong into a stationary
object.

Once the fork tubes have been bent back against the engine, then the
backbone tube, the bracing gussets and the engine cradle will distort.

But the steering head is normally loaded in compression, not backward
bending, when it reacts to the design bump, or whatever load you
encountered as you ran across the "ditch" you described.

The forks are trying to push the steering head UP, but the weight of
the motorcycle and rider prevent that from happening, and the springs
compress.

The function of the backbone tube is to transmit the load to the rear
suspension system and on to the rear tire contact patch.

It does this a bazillion times during the normal operation of a
motorcycle, without permanently bending.

>Yes, your steering head can easily survive a 7g bump without deforming
>the structure permanently.

While I find that probable, what is your source of info?
--
Stupendous Man,
Defender of Freedom, Advocate of Liberty

On Jul 14, 5:30�pm, "Stupendous Man" <s...@trap.com> wrote:

> While I find that probable, what is your source of info?

http://www.mikecauser.com/lotus/bibl...hipps1965.html

Mike Costin was head engineer at Lotus in the 1960's.

David T. Ashley wrote:
> The other day I ran my Honda Shadow through a ditch (going from Point A to
> Point B using the shortest route), and it was kind of a jolt when the front
> wheel started going up when it had been formerly going down (the bottom of
> the ditch).
>
> I'm sure it is all within design limits, but ... next time I have a few
> screws undone ...
>
> What is the right inspection procedure for the welds near the front of the
> frame? (I'm assuming just look for cracks everywhere?)
>
> Anything else I should know?

I'd worry more about the tire and wheel than
I would the frame. I'd expect damage to appear
there first. If you really bashed it hard, it wouldn't
hurt to inspect the rim and sidewall carefully. If
they're both OK, I'd expect the frame to be fine.