Re-furbing a Headlamp Shell

Tornado · Dec 16, 2019

My HiRider bike came with a strange headlamp shell...it's the correct 5-3/4" size for the fugly, red-headed, left-handed, step-child that is the HiRider, but it also has the three warning light holes rearward of the two position light switch. This places two of the three lights under the instrument clocks such that they are nearly impossible to see from the riding position without going into a high-speed tuck position.

To rectify and to further the conversion to the Roadster planform, I've scored an original 7" Lucas shell off fleabay for all of $14. It's in pretty reasonable shape, exterior chrome looking mostly intact with some rough-to-the-touch-ness on the upper surface. Interior is showing some good sized surface rust patches. The two mounting nuts are still holding their welds and the securing bolts/spacers need some rust removal.

I guess the biggest issue is a dime-sized ding on the underside below the left side mount hole. Any tips on how to deal with that? Tapping it out with a small hammer? Pre-Heating? Leave it be?

maylar · Dec 16, 2019

How are your sheet metal skills?

joe czech · Dec 16, 2019

I've worked out some small dings and dents in my 74's stainless fenders with a small automotive hammer and dolly set. i'm not a professional bodyman, but I managed to straighten things out to the point, that unless I point them out to you, you'd be lucky find them. stainless is one thing, chromed sheetmetal is another. if you have a hammer and dolly set, or access to one, work from the back side with light, very small taps, and work very slowly. work from the outer edges of the impression to the center. i'd protect the chrome surface with tape as to avoid damaging the chrome finish. if you need to polish the chrome, I found the same compound used on stainless (green buffing rouge), will buff out minor surface scratches on chrome. since the dent is on the underside, it won't be as noticeable. i would avoid heat. as they say, nothing ventured, nothing gained. good luck....

Tornado · Dec 16, 2019

maylar said:
How are your sheet metal skills?

NaDa!
I'm the guy that does the bondo work on all the used cars you've ever looked at ;-)

rvich · Dec 16, 2019

You might find it useful to have some kind of sandbag or shot filled bag to put the headlight shell against for tapping out that dent. A flat, hard surface, not. Even a thick catalog would be better than a bench.

You could off course use bondo and paint the shell.

gortnipper · Dec 16, 2019

Get a cheap bossing mallet, and use a sand bag. I used a half bag of grout I had laying around.

Lots of how to on doing that and you should be able to make progress.

baz · Dec 16, 2019

Use a polished flat plate
Settle the dent onto the the plate
IE in this case the plate would go to the outside of of the headlight
Get as much of the perimeter of the dent to sit on the plate
Then using a pointed wooden sheet metal mallet
Start tapping gently around the the dent
You will hear a sharp crack when you are exactly on the perimeter of the the dent
So working in a circular motion work around the the dent working your way inwards
Eventually the dent will be gone
Be sure to use a polished metal plate so you leave no witness marks in the chrome
The problem with using a sandbag is you could stretch the the dent the other way
And with any dent on any surface never hit the dent in the centre with the thought that it'll push back out this very rarely works
All the above is the way I have removed dents for years
No doubt there are plenty of other ways to deal with it, but this works for me
Cheers

Tornado · Dec 16, 2019

Lots of good tips here. Just to clarify, the dent is circular, concave (as viewed from outside surface) and dimpled. So Baz's remark about not starting at the center point will be well heeded.

maylar · Dec 17, 2019

There are also shrinking methods, where you heat a small spot to red hot and cool it rapidly. The metal shrinks and the dent returns to normal shape. This works for tanks etc that will be painted afterward but I'd be afraid it'd turn a chrome item blue. The heat can be applied with friction using a shrinking disc on an angle grinder, or with an electric spot heater. Stud welders often double as shrinkers. Both of these tools are body shop items.

rvich · Dec 17, 2019

TM Technologies web site has a lot of great information on it regarding metal work.

https://www.tinmantech.com/education/articles/shrinking-metal-dos-and-donts.php

You can practice on pieces of aluminum, brass or copper as they are all easy to work. It will give you some idea as to whether you want to start tapping on your headlight shell.

maylar · Dec 17, 2019

Thanks - that's certainly different than what I've read elsewhere.

gortnipper · Dec 17, 2019

My front fender before

And after a couple rounds with a bossing mallet and a trip to the polisher.

I had never used a bossing mallet before.

Tornado · Dec 18, 2019

Got it to a happy place. Wasn't a big dent at all really. Took about 30min of tapping with a small ball peen hammer. Did get a bit of "stipple" on outside, I guess from roughness of the hammers ball. Not fussed as it is on underside and not in line of sight.

Also soaked shell in Metal Rescue chelating solution for several hours and it did a good job on rusted areas on inside.

Now I just need a 7" reflector. Seems Walridge is having a sale on these

maylar · Dec 19, 2019

Tornado said:
Now I just need a 7" reflector. Seems Walridge is having a sale on these

Be aware that Lucas reflectors for new Triumphs won't fit the Commando headlamp shell. DAMHIK.

Tornado · Dec 19, 2019

This is the Lucas type I'm looking to get:

It has a part number on the vendor site (MotoParts Inc for this example) of 391516798.
Walridge lists a similar unit with the number & item description of: 516798G LIGHTS RH DIP GENUINE LUCAS N

maylar · Dec 19, 2019

No pic there...

I bought this one and the glass rim is thin and the Norton hold down clips are too short to hold it into the headlamp rim.

https://www.classicbritishspares.com/products/lucas-modern-headlight-units

Tornado · Dec 19, 2019

maylar said:
No pic there...

I bought this one and the glass rim is thin and the Norton hold down clips are too short to hold it into the headlamp rim.

https://www.classicbritishspares.com/products/lucas-modern-headlight-units

That's an H4 reflector, perhaps that's the difference? Also, are you aware there are two lengths of the wire clips available?

Short:
https://www.eurojamb.com/collection...retaing-spring-clip-set-triumph-norton-bsa-sh

Long:
https://www.eurojamb.com/collection...-retaing-spring-clip-set-triumph-norton-bsa-l

maylar · Dec 19, 2019

Tornado said:
That's an H4 reflector, perhaps that's the difference? Also, are you aware there are two lengths of the wire clips available?

Short:
https://www.eurojamb.com/collection...retaing-spring-clip-set-triumph-norton-bsa-sh

Long:
https://www.eurojamb.com/collection...-retaing-spring-clip-set-triumph-norton-bsa-l

Nope. I didn't know that. Thanks. I bought it with the intent of using it with Goffy's 5K H4 light, as Fast Eddie reported that the Lucas reflector had better light than a Wipac.

Tornado · Dec 19, 2019

maylar said:
Nope. I didn't know that. Thanks. I bought it with the intent of using it with Goffy's 5K H4 light, as Fast Eddie reported that the Lucas reflector had better light than a Wipac.

So is the fitment issue you found more than just needing the different/longer clips?

rvich · Dec 19, 2019

7" Volkswagen reflectors fit the shell. Not sure about clips but a lot of the vintage VW reflectors are H4, LED ready. Here is one that even has a parking light.

https://www.busdepot.com/hq6014

Re-furbing a Headlamp Shell

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