Author Topic: c11g a/r unit  (Read 851 times)

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Online kdm

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c11g a/r unit
« on: December 31, 2018, 11:55:28 am »
Hi, C11g, 1954, advance/retard unit
Can set timing when static ok but when running stutters and doesn't pick up.
Looking at the a/r unit it has broken the backplate of unit from the part on camshaft, if that makes sense!
If I'm describing this correctly it means the a/r is free of camshaft.
So looking for some advice on how to get part on the camshaft off as it seems stuck real bad
Or would it be possible to braise it in place then mess about with timing?
thanks kev
1954 C11g

Offline Ginge

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Re: c11g a/r unit
« Reply #1 on: December 31, 2018, 12:17:18 pm »
The back plate has a tapered cone mounted to the back off it.  It locates into an internal taper on the end of the cam.

Are you saying that the back plate has separated from the tapered cone, and that the cone is stuck inside the end of the cam?

If so don't go applying heat and brazing.  It will ruin the hardening on the cam.  Much better to try and extract the broken piece with an EzyOut or an old tap. Or cut a slit in it with a Dremel bit and collapse it.  Your auto advance unit is probably not repairable so you might as well sacrifice the tapered cone.

Is it rusted/seized in place or just tight on the taper? Give it a tap with a small punch.  It might break free.
Ginge.

Online kdm

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Re: c11g a/r unit
« Reply #2 on: December 31, 2018, 12:35:04 pm »
tapered cone was words looking for
here is a pic
1954 C11g

Online kdm

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Re: c11g a/r unit
« Reply #3 on: December 31, 2018, 12:38:28 pm »
not obvious from this pic but cone and backplate have solder on them, bodged in the past maybe?
1954 C11g

Offline Pete

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Re: c11g a/r unit
« Reply #4 on: December 31, 2018, 12:46:23 pm »
I'd put a piece of tube over the shaft, old box spanner or something, a bit longer than the shaft, then a washer and screw a bolt into the threaded end of the shaft. Tighten bolt and it should ping off. If not, once bolt is tight, tap end with hammer.
Pete
1948 BSA C11
1932/56 C12Rudge
N.B. Andromeda
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Offline Ginge

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Re: c11g a/r unit
« Reply #5 on: December 31, 2018, 01:16:08 pm »
Yep, as Pete says.  Gently Bentley pull that out.  That's a bodge, and you need a new AAU.

Sometimes you can break the taper with gentle taps up-down-left-right on the exposed shaft but Pete's way is a better way.
Ginge.

Online kdm

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Re: c11g a/r unit
« Reply #6 on: December 31, 2018, 01:31:56 pm »
tried, never moved at all
would some gentle heat be ok?

does anyone know where to get a replacement unit or is it like looking for hens teeth?
1954 C11g

Offline Pete

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Re: c11g a/r unit
« Reply #7 on: December 31, 2018, 01:38:19 pm »
Gentle heat should help. Keep the bolt tight as you apply heat. Good luck.
Pete
1948 BSA C11
1932/56 C12Rudge
N.B. Andromeda
Volvo V40

Offline camman3

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Re: c11g a/r unit
« Reply #8 on: December 31, 2018, 04:46:01 pm »
They are getting a bit like hens teeth, but do come up on ebay ...occasionally.
Don't chuck the shaft when you get it out...as you may well need to adapt it to fit an E.I unit if forced to go down that road.
Graham
1957 C12
In sunny (sometimes) Christchurch, Dorset, UK

Online kdm

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Re: c11g a/r unit
« Reply #9 on: December 31, 2018, 05:01:07 pm »
hasn't moved yet, given up for this year as it is Hogmanay  and some drink is forecast ;)
Thanks for the replies
1954 C11g

Offline ianinglis

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Re: c11g a/r unit
« Reply #10 on: December 31, 2018, 06:05:29 pm »
tried to reply but keep getting an error message??
BSA C10L 1956 - JFO 588
BSA C10L 1954 - MVE 107
RM6 RALEIGH RUNABOUT
ENFIELD DIESEL KUBOTA OC 95
BSA M21 RIGID RKN 816
CBF 1000
BSA ARIEL 3

Offline ianinglis

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Re: c11g a/r unit
« Reply #11 on: December 31, 2018, 06:08:47 pm »
the end of the shaft has an internal thread
find a piece of round bar or a bit of an allen key or anything else that will fit down the hole and cut it so its about 12 mm short of the end of your shaft so you can see some threads then find a screw or bolt the same thread and screw it in the hole until it touches said rod then give it a good nip with a spanner and the whole thing should fall off in your hand (if that makes any sense)


ian
BSA C10L 1956 - JFO 588
BSA C10L 1954 - MVE 107
RM6 RALEIGH RUNABOUT
ENFIELD DIESEL KUBOTA OC 95
BSA M21 RIGID RKN 816
CBF 1000
BSA ARIEL 3

Offline timsdad

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Re: c11g a/r unit
« Reply #12 on: January 01, 2019, 08:10:28 am »
Yes, there's no reason that I can see why this shaft can't get removed in the normal way. The paraphernalia missing from its outside shouldn't make any difference to the fixing and unfixing of the thing.

Rat
« Last Edit: January 01, 2019, 08:20:24 am by timsdad »
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Offline camman3

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Re: c11g a/r unit
« Reply #13 on: January 01, 2019, 09:20:54 am »
Pete suggested that earlier, albeit with a tube or socket over the shaft which should make it even easier.
Kdm suggested he'd tried that and it didn't work.???
I had one on my c12 that was difficult to remove, and in fact I stripped the internal thread during first attempts
I re tapped to 5/16 or m8 and succeeded with a couple of whacks.
Graham
1957 C12
In sunny (sometimes) Christchurch, Dorset, UK

Offline timsdad

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Re: c11g a/r unit
« Reply #14 on: January 01, 2019, 02:19:09 pm »
Sometimes these things can take a bit of perseverance but they all shift in the end. You just have to get a bit more imaginative, or use a bit more force and/or heat, to move the bastard.

It's just experience that teaches you what the minimum of force or tweaking is needed - often the hard way.


Ray
Just a motorcyclist.