Author Topic: New to me BSA C11, questions  (Read 596 times)

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Online timsdad

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Re: New to me BSA C11, questions
« Reply #30 on: May 22, 2020, 02:52:25 pm »
I stand corrected - memory going more than I thought. I've just looked at pictures of my C11G and it did, indeed, have a head steady to the front frame tube. I suppose I was thinking of the rearward one on the side-valve 350 - sorry.

Ray
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Online craigc11g

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Re: New to me BSA C11, questions
« Reply #31 on: May 22, 2020, 03:03:28 pm »
no I think its me , just been looking thro some spares and found a c11g top end with no head steady casting ? also the push rod tunnel section is taller , this looks more like the top end in question here so now I think this engine did not have a head brace fitted . sorry my mistake , im no expert that's for sure  :-[

Online donkey

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Re: New to me BSA C11, questions
« Reply #32 on: May 22, 2020, 03:16:42 pm »
Craigc11g the head steady bracket is clearly illustrated in the B.S.A. sheet you posted so I would say they did have it
donkey

Offline johnintexas

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Re: New to me BSA C11, questions
« Reply #33 on: May 22, 2020, 03:21:26 pm »
I am no expert but I think this is correct

Here is that Ah ha moment.  Simple but effective. 
Thank you.

John in Texas

Offline John M

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Re: New to me BSA C11, questions
« Reply #34 on: May 22, 2020, 03:36:42 pm »
The C11G cylinder heads have the casting lug and hole for the steady, but the C11 heads I've seen do not. Presume that the head steady was standard on the later heads only.


Offline johnintexas

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Re: New to me BSA C11, questions
« Reply #35 on: May 22, 2020, 03:40:33 pm »
The C11G cylinder heads have the casting lug and hole for the steady, but the C11 heads I've seen do not. Presume that the head steady was standard on the later heads only.



I haven't been out to the workshop today. Next on my list.  I will check it out and report back.
Thanks to all for your help.
John in Texas

Online craigc11g

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Re: New to me BSA C11, questions
« Reply #36 on: May 22, 2020, 04:15:31 pm »
sounds right , maybe when they went from dizi too points on the side and alt , less finning on the earlier ones also looking at this , I may have some cases for this

Online timsdad

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Re: New to me BSA C11, questions
« Reply #37 on: May 22, 2020, 06:39:17 pm »
Yes, the only head steady in my early parts book is for the side valve C12, none for the 250s until the C11G, and as the query was for a C11 then the correct answer was probably no.

It's possible that the dynamo acted as some sort of balance shaft and the change to a heavy rotor on the end of the crank may have lead to an engine vibration that needed a head steady. The shock absorber had also moved from the engine to the transmission.


Ray
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Offline johnintexas

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Re: New to me BSA C11, questions
« Reply #38 on: May 22, 2020, 07:35:11 pm »
The C11G cylinder heads have the casting lug and hole for the steady, but the C11 heads I've seen do not. Presume that the head steady was standard on the later heads only.



I haven't been out to the workshop today. Next on my list.  I will check it out and report back.
Thanks to all for your help.
John in Texas
Well you are right, there is no lug on the cylinder head. Bummer! 
Busy stripping the primary off so I can lift the engine unit out and clean up the horrible welds and 40 years of gunk in every nook and cranny.
I know I have said this before but thank you all.
John in Texas

Online Cosmikdebriis

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Re: New to me BSA C11, questions
« Reply #39 on: May 22, 2020, 07:53:21 pm »

It's possible that the dynamo acted as some sort of balance shaft and the change to a heavy rotor on the end of the crank may have lead to an engine vibration that needed a head steady. The shock absorber had also moved from the engine to the transmission.


Ray

That or they just became fashionable?

If it had been an oriental machine it would have come with a nice little sticker on the side panel so everyone could tell  "New BSA C11 HS" and no doubt plenty of advertising literature to tell you exactly why you needed to trade in your old non "HS" model for a new one.

Just imagine the shame of not having one when all your mates did. ;D
A bike on the road... Is worth two in the shed...

Online timsdad

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Re: New to me BSA C11, questions
« Reply #40 on: May 23, 2020, 08:54:42 am »
You may be right, Cosmik, but I doubt BSA were too worried about fashion, and the opposition, in 1954.

They were fitting head steadies to other much earlier models, -  the 1940 350 C12 and the pre-war B29, M Series and the big V Twins.


Ray
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Online craigc11g

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Re: New to me BSA C11, questions
« Reply #41 on: May 23, 2020, 09:01:23 am »
what does HS stand for ? in know GT , just interested

Online Cosmikdebriis

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Re: New to me BSA C11, questions
« Reply #42 on: May 23, 2020, 09:21:36 am »
what does HS stand for ? in know GT , just interested

Head Steady. All meaningless inventions have to have an abbreviation and sometimes, in small print somewhere on the same sticker, the whole thing just so long as it's too complicated for the average rider to fully understand but at least can be satisfied that they have whatever it may be ;)

By the way. I was kinda joking but perhaps not the right place.

To be a little more serious. The design of the introduced head steady is a bit of a bodge. It should have gone to something like the headstock casting and not a collar round the downtube. Too expensive no doubt.
A bike on the road... Is worth two in the shed...

Online timsdad

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Re: New to me BSA C11, questions
« Reply #43 on: May 23, 2020, 09:31:35 am »
All these letters have a meaning, the trick is figuring them out and remembering them. As in 'Rally Sport', 'Super Sport', 'Sport Frein Competizioni', 'Race Developed Liquid Cooled' and 'Yamaha Power Valve System'.

Ray
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Offline c11jim

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Re: New to me BSA C11, questions
« Reply #44 on: May 23, 2020, 12:20:57 pm »
Johnintexas, don't worry about a head steady. You don't need it on a C11. That bracket with the crappy weld was probably put there to try to support the broken crankcase. You need to replace or repair the crankcase and then everything will be solid again.
Jim