B50 7" Headlamp

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B50 7" Headlamp

Post by Dazzle » Tue Dec 03, 2019 9:58 pm

Hi all,

My 1971 B50T came back to these shores a few years ago after spending it's life in Canada. The Headlamp is not the 5½" Lucas MCH66 but a 7" Lucas Headlamp with a near 'flatback'. It could be a WW10156L - but I'm not sure. Question: Did BSA ever fit as standard 7" Headlamps to their B50 'export' models ? Of course the Christian thing to do is put a photo of it on here but the garage is freezing tonight and someone might know the answer ? Cheers.

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Re: B50 7" Headlamp

Post by BSA_WM20 » Tue Dec 03, 2019 11:20 pm

Mine has the 7 " pancake light .
I am in OZ
And yes BSA specs were different in different markets and always have been right back to the 20's .
I have a 26 & 27 B2 Both are the same but they are substantially different to what the parts book says they should be.
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Re: B50 7" Headlamp

Post by JB » Tue Dec 03, 2019 11:28 pm

As far as I am aware every Triumph & BSA oil in frame unit single and all of the Triumph C series twin variants, left the factory fitted with a Lucas 5" MCH66 headlight. If it has a 7" headlight it was almost certainly fitted later on.
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Re: B50 7" Headlamp

Post by Dazzle » Wed Dec 04, 2019 11:39 pm

JB - I hear what you say (or read what you wrote) and certainly my Parts Book does specify the Lucas 5½" MCH66 Headlamp as you mentioned but as BSA-WM20 said 'BSA specs were different in different markets' and this might apply to the 7" 'Pancake Light' fitted to bikes that 'crossed the pond or maybe it did leave the factory with the MCH66 but in order to get it through the USA/Canadian laws it was changed to the 7" over there ?

Thanks for your comments.

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Re: B50 7" Headlamp

Post by Jeff K » Thu Dec 05, 2019 4:06 pm

If you do try to fit the smaller head light, I believe mounting wire brackets are different. I seem to recall that they had three different sets of them.
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Re: B50 7" Headlamp

Post by JB » Thu Dec 05, 2019 11:49 pm

The only difference between the different export versions would have been the dip pattern fitted to the MCH66 shell, just as there was only style of taillight and indicators irrespective of what market it was sold into.

I am as certain as I can be that 7" headlights were never factory-fitted items to our bikes.

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Re: B50 7" Headlamp

Post by Dazzle » Fri Dec 06, 2019 2:47 am

Jeff K - Thanks for that Jeff. My friend said that the Wire Mounting Brackets on my B50T didn't look like they would be practical if I changed the Pancake Headlight for a MCH66 which sort of makes sense if as you say there are 3 different sets for them. This has made my mind up to stick with the Pancake Headlight for the time being although I will upgrade from BPF to H4.

JB - thanks for your input. IMO the MCH66 is as iconic to the mark as the diagonal stripe is down the fuel tank but since Jeff K's comment re 3 different types of Wire Mounting Brackets I've decided that's a job maybe for the future ?

:thumb

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Re: B50 7" Headlamp

Post by Jeff K » Fri Dec 06, 2019 3:47 am

Even the small MCH66 headlights came in different versions. The B25/T25T/B50/SS/H/T used MCH66/60262A with a rotary switch in the middle and the three indicator lights were like a "V" around it. The TR5T used the MCH66/00-1253 with a toggle switch with the indicator lights in a row under it. Picture on page 41 of the "O.I.F. B25/B50: the Incomplete Guide" book by Brad Jones/Kevin Hawkins. good book to have.
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Re: B50 7" Headlamp

Post by JB » Fri Dec 06, 2019 10:07 am

As far as I'm aware all larger BSA/Triumph's models used wider spaced steel fork yokes with the 7" pancake headlight, the 650 Trophy & Firebird were the only exception and they needed a different wire stay (third version) to take the smaller MCH66 headlight that was fitted across our range of bikes.

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Re: B50 7" Headlamp

Post by malcward » Fri Dec 06, 2019 6:48 pm

Yes there was yet another version for the Rocket 3 and Trident, with the 7" shell . Cheers malc

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Re: B50 7" Headlamp

Post by JB » Fri Dec 06, 2019 11:42 pm

malcward wrote:
Fri Dec 06, 2019 6:48 pm
Yes there was yet another version for the Rocket 3 and Trident, with the 7" shell . Cheers malc
The very same forks and electrical hardware as Triumph/BSA unit 650 twins with twin carbs!

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