I made a bracket from aluminum angle, to mount my chrome, mini-bullet turn signals just where I wanted them, on the licence plate bracket. I made tech drawings, four prototypes, then the final product. Polished it up real good and mounted it - Perfect!

Its been on the bike for about four months. The other day I rode to a mate's place and when I got there, the left turn signal was hanging from the wires and had been swinging against the tire. The bent arm had snapped off. The other side showed no signs of fatigue, but I did little more than touch it, and it also snapped off!! The turn signals are now mounted in the rear-most fender-rail holes.

It got me thinking about other 'simple' mods I've made. In particular, the aluminium spacers I made for the handlebar risers. I had to buy longer bolts - and I had to make the hex-head smaller to fit in the OEM handlebar clamps. That mod is now on my mind a bit!

Does anyone else want to share their 'mod fails'. It might make for some informative reading.

A similar thing happened on my bike but it wasn't a mod.  The license plate cracked in two just below the bracket bolts, a clear case of metal fatigue.  There must be a fair amount of vibration in the back.  I made a backing piece out of 1/8 inch stock, drilled some extra holes and bolted it back on.  That's not the first time a license plate cracked on me.  When I rode British twins in the sixties it was fairly common, even the fenders would sometimes crack from fatigue.

I lost my licence plate recently too. I think the previous owner had backed it into something as it had a slight bend in it. It eventually cracked. A friend told me it would drop off. I didn't believe him. One day I got up in the morning and noticed the plate was gone - just a strip left under the bolts. Some f the local roads around here are a pretty patchy, so the rear probably gets a fair bit of stress.

By the way, I wasn't happy with the LED signals either. They just weren't bright enough in daylight. I managed to find the same thing in a halogen (E rated) version, with amber lenses. They have the exact same housing, and internal mount for the globes - so at least I have a spare set of housings if I  ever damage them.

SoC wrote on 11/19/17 at 18:54:58:



Hey SoC, thanks for the tips  

To answer your questions, I tried a few different methods of bending the aluminium.

1. I put it in a vice and yanked it - snapped right off.
2. I put it in a vice and tapped it with a hammer - ended up obviously weak.
3. I held it by hand over the corner of the anvil-flat on my vice and peened it with a hammer, kind of working the radius as I went. I was careful not to go too far, so I didn't need to bend it back out at all.

The last method seemed to produce a good result. It withstood a moderate test of putting some pressure on it by hand. I thought it was pretty good, and went with that.

I was surprised after a few months when one arm fell off! I was especially surprised by the intact one. It showed no signs of fatigue, but it broke off with the slightest pressure.

I've now mounted the signals in the fender-rail holes to keep me on the road. I was going to make a new bracket from mild steel, and weld instead of bend. But, I kind of like them where they are now, so I'm re-thinking the setup. I want to add some kind of capacity to carry a small bag on the back, even if I carry a passenger. I'm thinking about a custom made sissy bar - I just don't like the stock fender-rails which the OEM sissy bar attaches to. I'm not in a hurry so I'll take some time to think, sketch, and prototype. A friend of mine knows a guy that does that kind of custom work, so I'll probably pay him a visit eventually.

In the mean time, I'm waiting for my Triumph Superbars to arrive for the other end of the bike!!

Dave thanks for the soap tip on heating aluminum. Heating aluminum is tricky though and self tempering works with some alloys and not with others.

Another applying heat related tip for those who have ever tried to paint aluminum parts, heat does wonders to get primer to adhere. If you heat the aluminum with a heat gun before spraying primer it creates better bonding to the aluminum.

You don't need to heat it real hot. How it was explained to me is that there is a slight expansion of the surface and when it cools it locks the primer into the surface better. This assumes it was sanded and acid etched. If heated too much though it can flash the solvent too quickly and cause primer to bubble and fail immediately.

I have been a machinist for over 40 years, and have worked with many types of metal.

However, a word of warning.  ANY metal you purchase at a hardware store, or big box store is not the same quality as that purchased by local machine shops, etc.

My recommendation is to pay a little extra and get your small pieces of metal from McMaster-Carr.  They have an excellent online format, and over the years as a Purchasing Manager in various places, I have never had one bad experience with them.

You guys have given me an uh-oh moment. I made my rear turn signal mount by bending and cutting some aluminum flat bar from Home Depot and I painted it with liquid rubber paint. If it is cracking there is no way I am going to know until it actually breaks.