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What's this hole for?

Submitted by john_tickell on Mon, 23/05/2016
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1952 plunger frame, hole below the near side pillion foot rest taped 7/16 cycle thread, what's that for? John

Submitted by richard_payne on Mon, 23/05/2016

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A photo would be helpful. Is it not that they had a habit of using the same lugs on both sides of the frame...Is it a duplicate of the silencer mount ?

Submitted by michael_rettie on Mon, 23/05/2016

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Richard is right. The castings have the same # and are both machined for the silencer bolt. Easier for production, I guess.

Submitted by john_tickell on Tue, 24/05/2016

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Shall have to take the silencer off and have a look, its held on with a nut and bolt. Never realised that was a threaded hole. Bum size 7/16 tho. John

Submitted by john_tickell on Tue, 24/05/2016

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Shall have to take the silencer off and have a look, its held on with a nut and bolt. Never realised that was a threaded hole. Bum size 7/16 tho. John

Submitted by dave_graham1 on Sat, 28/05/2016

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Previously Michael Rettie wrote:

Richard is right. The castings have the same # and are both machined for the silencer bolt. Easier for production, I guess.

I don't think it's for the silencer bolt, the silencer is up swept and a lot higher than that bolt hole. Mine is mounted on the rear footrest bolt. The holes are unused both sides. The first thing I thought of was it's for a rear stand, but it looks too low for that as well.

Here's a picture of the hole on the exhaust side and you can see the hole on the other side.

[URL=http://s1080.photobucket.com/user/Horror/media/DSC_0102_zps5rlzd8nl.jpg.html][/URL]

Submitted by mikael_ridderstad on Sat, 28/05/2016

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Without knowing, my assumption is that it could be mounting holes for a sidecar. They are on both sides so you can have a sidecar on either side of the bike.

Submitted by john_tickell on Sat, 28/05/2016

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That's the one Michael. I haven't removed the silencer yet to have a look to see if it is also threaded 7/16 Cyc.

I have been side tracked at the moment. Set off for a long ride yesterday and 10 miles out the rear chain broke. It was the split link that had failed. No I did not carry a spare! When eventually back at home discovered the rear chain is a Regina and Renolds links are not compatible. Will now have to source a suitable replacement. Never had this trouble on my old BMW. Happy Days. John

Submitted by ian_richtsteig on Wed, 01/06/2016

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John,

I've checked my plunger frames for my Model 30, ES-2's and model 7's and all have the same arrangement so I can only conclude that the same rear plunger mounts were used on all singles and twins. All of mine are threaded 7/16 BSF and the left hand one takes the model 7 muffler bracket.

Submitted by boo_cock on Wed, 01/06/2016

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That was for the rear stand on the 1939 and prior ES2 and Inter models.

Deleted after the war for obvious safety reasons and a centre stand was fitted.

 


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