47 U model forwards...

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Prof
Founder, Choppers Australia
Posts: 5622
Joined: Sat Oct 22, 2005 3:54 pm
Location: Willunga, South Australia
Contact:

47 U model forwards...

Post by Prof » Wed Jan 04, 2017 10:59 pm

A few weeks ago, Sam brought up his recently purchased 47 model U. Model U's were 1200cc sidevalves and in their day were used mainly for sidecar work. The SA police used them. My father told me how he was riding his '34 Velocette in the city and a pair of coppers in a U sidehack came around a left hander and the front wheel got caught in the tram lines. The sidecar lifted up in the air and almost tipped before the weight of the big copper in the chair pulled it back to earth. Dad thought it was a real scream!

Anyway Sam's is in an aftermarket rigid frame. He replaced the Japanese front end with a genuine modern HD springer, but the bearings are wrong and we will replace them in the near future. Sam's immediate concern were the forward controls which were too far forwards. The foot clutch was almost unusable and the controls were totally worn out and loose.

The U runs an SU on a very long manifold which made put the left leg way out to the side, so we had a bit of work ahead of us...
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Up on the stand; SU poking out...
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Right side gives a good view of the chopper's lines...
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Worn out and neglected and way too far forward...
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Let side foot clutch...
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Another shot of the carby hangin' way out thar!
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With Sam on the chopper, we worked out the footpegs needed to come back 6" (see testa mark). Diagram shows measurement between frame and footpeg centre which suited both sides...
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Took quite a bit of measuring to find a suitable spot where both would be aligned with one another...
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Next step was to get the chopper vertical so we could get controls level. Easiest way to level a bike is off the sides of the rear wheel...
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Sam chose a set of knurled steel footpegs I'd had in the shop for some time. We worked out to use the supplied footpeg mounts and extend them so the lever pivots would have some where on which to roll. On diagram, extension shaft is marked with angled lines running up to the left. The pivot is marked with lines running up to the right. This is known as a sectioned drawing...
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Shaft extensions being machined in the lathe. Internal thread here being done with a thread tap. Lathe is put into neutral and the chuck rotated by hand. Spanner holds tap from turning. Starting thread this way keeps it in alignment...
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Finished shaft screwed onto footpeg mounting and the slight misalignment tidied on the linishing wheel...
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New mounting blocks cut out of 12mm steel and tapped for 3/8UNF bolts. They need to match each other, so this little level is used to get the angle matching...
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Spirit level to keep them upright...
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Tacked into place...
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Final check to find comfortable height...
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Aluminium template...
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... transfered to 12mm stainless steel bar...
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Location of top hole. Halfway point across bar found using dividers...
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Same distance measured from top...
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Centre of hole centre punched and curve marked. Hole will be 1/2"...
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Finishing rounding on linishing machine. Note that bracket is held vertically not horizontally to easily keep it square...
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Mounted in place (top yet to be rounded on this one)...
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Footpeg on shaft mounted and heights each side double checked...
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More to come...
Chopit'nrideit... Prof

Prof
Founder, Choppers Australia
Posts: 5622
Joined: Sat Oct 22, 2005 3:54 pm
Location: Willunga, South Australia
Contact:

Re: 47 U model forwards...

Post by Prof » Thu Jan 05, 2017 10:50 pm

While we were working, Bob from Queensland rolled in to organise a couple of tidy up jobs on his CB750 chopper, which he especially drove back to Qld to bring it back down for our Chopper Muster...
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Back to the U model... as mentioned at the beginning, the SU pokes out a long way and prevents a comfortable leg position. A bit of measuring demonstrated we could knock an inch and a half of the length of the manifold. We were also able to fold the manifld forwards 5 degrees so that by...
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... rotating the float bowl a quarter of a turn we could gain further clearance because the fuel hose now moved away from the cylinder and could be rerouted under the carb. Now quite comfy for that left leg...
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We found some radiator hose the right diameter to replace these worn out manifold rubbers...
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Sam didn't want anything too fancy for the levers, but agreed that curving them would add a cool touch. 25mm x 5mm stainless flat bar is heated and bent. It tends to twist so has to be flattened on the anvil...
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Once the curve is completed, final straightening with a big mother of a very old wrench is done...
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Measuring up across the curve. 170mm centre to centre seemed about right...
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Brake lever pushes a pushrod to operate the rear brake linkage, so a small tab is made out of 25x5 flat stainless...
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Lever welded on and being set up to get the right location for the pushrod tab...
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Linkage has seen lots of miles and is badly worn. This hole is drilled out from oblong 3/8" to 1/2"...
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A pin is made that is a close fit in the new hole. It is stepped up to allow a 5/16" threaded hole for the brake rod...
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New stainless linkage needs a tight bend to clear the exhaust and line up with the forwards...
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Sam was keen of toe pieces that matched the footpegs. Jake turned them up out of aluminium. Knurling sure looks the goods...
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Brake linkage and lever fabricated. An aftermarket heim joint is threaded to the front end of the linkage...
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Another view...
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Original forward control brackets are cut off, cleaned up and the frame temporarily repainted...
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Clutch lever and linkage fabricated and polished. No waiting 6 weeks for chrome plating! The clutch lever pulls on a stainless cable a stainless clevis from a yachting supplier. Both ends are 'squeezed' on with a hand operated hydraulic swager, a very handy tool that is not overly expensive...
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Another view to show the clevis more clearly...
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Brake side polished and frame cleaned up...
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Another view of the rear brake linkage...
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The full set polished and shining in the sun...
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Sam reckons his new forwards are the ants pants and he loved being a part of the fabricating process...
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Of course, he couldn't wait to give her a blast...
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Chopit'nrideit... Prof

Youngblood
Posts: 341
Joined: Wed Oct 24, 2007 1:48 pm
Location: North-Eastern suburbs- Adelaide

Re: 47 U model forwards...

Post by Youngblood » Sat Jan 07, 2017 11:24 pm

Nice...................
8) 8) 8)
Youngblood

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