Sunday, April 10, 2016

Fixing Motorcycle Mirror

Fixing a broken motorcycle mirror

Difficulty Level (Easy, Medium, Hard, Insane):

My bike accidentally tipped over and broke the mirror off. Sure, I could have just went to the store and bought a new one, but even at $35, if I fix 100 thing and save $35 each time I can pay for our next vacation.

This one turned out a little more tricky than anticipated because these mirrors are not meant to be fixed. The way they work is inside the mirror is a semi-spheric washer with a spring inside. That part fits into the semi-spheric plastic portion of the mirror housing. Then comes a trumpet shaped washer on the outside essentially sandwiching the plastic part of the mirror between the trumpet shaped washer and the semi-spheric washer.

This all is tied together with a bolt and a nut. unfortunately, part of the plastic broke off and the only way to fix it was to take the bolt and all the parts completely apart.

I'm assuming when they manufactured these mirrors, they made the housing first, assembled the bolt, spring and washer combination and only THEN pressed the mirror into the housing. Unfortunately, there was no way for me to take the mirror out of the housing without damaging it so I had to come up with another solution.

I turned down the bolt and put a nylon-washer locking nut on it, then assembled everything loosely, put the two washers into the mirror housing. At first, I tried to use mitre-bond to glue it but the pressure on that little part was too much to handle so I ended up having to plastic weld the broken off piece back onto the mirror housing. When that was all done I was able to tighten the nylon locking washer to create some pressure between the two washers and the plastic mirror housing.

Since everything was going to be covered with a rubber protecting sleeve, it didn't really have to look pretty which I was glad about because this is the first time I actually attempted to plastic weld anything.

The mirror housing was black abs and since I didn't have any plastic welding rods, I just cut a piece out of a 2" ABS drain pipe, rounded it on the bench grinder and used an electronic soldering gun to melt the ABS and weld the two parts back together.

All the parts with the broken piece of mirror housing
Turning down the bolt that holds all the parts together
After the nylon-washer locking nut was installed on the bolt
The loosened bolt back in the mirror housing
Mitre-bonding was not strong enough for this application
The plastic welded parts
My electronic soldering gun with a strip of ABS off a drain pipe
The fixed mirror back on the motorcycle
Table saw
Electronic soldering gun
Metal lathe and accessories
Tap & die set

4" of 1/8" by 1/8" ABS




Another one hits the dust


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