Frame question

Started by Peter 100, January 27, 2022, 06:35:12 PM

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Rick Parkington

Agreed David, I think that's the standard place for it. My unrestored '32 9A came with a head steady fitted from there to
one rocker box bolt.
Cheers Rick 

DavidG

Quote from: phutton on January 28, 2022, 10:46:20 AM
I used mine to mount a head-steady!

A less obtrusive head-steady mount is the earthing bolt just behind the cylinder head. Make up a straight bar to the top stud on the rocker box. It does smooth things out a bit (even more, I should say!)

Thomas

The reason why I dismantled my complete motor were high frequency vibrations visible in the central girder spring (see http://www.marston-sunbeam.org/technicalNotes/model9EngineRebuild.html). Beside that I never had excessive vibration at the head. Vibrations are caused by technical glitches (a worn ball bearing at the crank shaft, for my case). So, I would assume that an extra connection to the frame is not necessary. There is a connection between barrel and frame at my BSA C11, though.
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

phutton

That is the theory, although whether it works is another question entirely!

P.

Peter 100

Paul is that to give extra support to stop vibration?
Peter
1934 Sunbeam model 9 🏍️
1946 Austin 10 🚙

phutton

I used mine to mount a head-steady!

P.

Peter 100

Steve and singleminded
Thanks for that it does make sense i never thought of that about the sidecar doh! 😁
Yes there is another under the seat.
Cheers chaps
Peter
1934 Sunbeam model 9 🏍️
1946 Austin 10 🚙

Greybeard

Its a mounting for a sidecar tube, Peter - most British bikes of 350 or more from the 20s onwards have them. Sometimes used for crash bars or badge bars. Therell be similar mounting point elsewhere on the bike, such as below the saddle, and lower down on the frame.

Steve
1916 Triumph Model H
1926 AJS G8 500cc ohv
1937 Sunbeam Lion 500cc
1949 Matchless G80S
1952 BSA A10 Golden Flash
1953 Matchless G9
1953 BSA B31
1958 Ariel NH350 Red Hunter
1961 Matchless G80
1961 AJS M31 De Luxe 650cc
1961 Panther M120 650cc
BMWs R100RT - R80 - F650GS
1960 Rover P4

singleminded

It's the upper front side car mounting lug.

Peter 100

Hello everyone
This might be a daft question but what it the hole for indicated on the frame?
I have seen a photo online with something that is chrome plated in one but cannot make out what it is.
Thanks
Peter
1934 Sunbeam model 9 🏍️
1946 Austin 10 🚙