1961 CB72 Project

G-Man · Post by **G-Man** » Mon Jun 23, 2014 10:15 am

Greg

Thanks for your comments. I have a spare early barrel and pistons to put this one back to 250cc and the big bore kit can go into one of my other projects. I would really like to get a 10mm plug head to go on there sometime as well. The idea with this bike is to get it as close as I can to factory spec.

The strange thing is that Alan Curtis has a similar bike within a few numbers of this one and both have some strange features that I wouldn't expect to find, such as chrome plated side panels, chain guard and rear shock springs. I realise that those are not commonly accepted factory spec items but it does seem a bit of a coincidence...

G

Hamamatsu Nippon · Post by **Hamamatsu Nippon** » Mon Jun 23, 2014 10:28 am

Interesting project. Good luck with your search for the hard to find and unobtanium parts. If I see anything around here I will let you know.

G-Man · Post by **G-Man** » Mon Jun 23, 2014 10:38 am

HN - thanks.

I would appreciate any help that you or anyone can provide. :-)

G

sarals · Post by **sarals** » Mon Jun 23, 2014 10:52 am

Graham, I can't provide much help but I'm long on inspiration and even longer on awe! I was absolutely aghast when I saw the sorry state it was in. I thought it had been under water! But, what a machine. It's so different than the 305 I know so well, it's almost hard to believe they share a lineage. That brass data plate, for instance - wow. I understand why you so want to bring it back. I positively can not wait to see what you do with that beauty!

G-Man · Post by **G-Man** » Mon Jun 23, 2014 11:23 am

Sara

It was your restoration thread that got me thinking that I ought to share this one. I have already had a good deal of help from friends on this forum and elsewhere.

This bike laid the path for your CB77 and with those big pistons proved that it could survive both in the hands of English boy racers and a prolonged stay in a damp shed. The engine had such good compression that it was tempting to clean the carbs, put on a battery and see what happened.

Judging by the about of black sludge that was in the bottom end of the engine I was glad I didn't.

Please feel free to chip in at any time; you have championed over your project and I hope to do the same with this one.

Now, it's time to gently take the dremel to the rivets on that brass plate so that the frame and swing arm can take a trip to the blasters.

G

G-Man · Post by **G-Man** » Mon Jun 23, 2014 4:45 pm

Some more details from this bike..

Footpeg hangers. These are fresh from my ultrasonic cleaning bath. The 40 odd years of grime has come away showing the natural shine. No cracks and not bent either. Despite the fact that they are thinner, they look and feel stronger than the later design.

footrest hangers by graham.curtis, on Flickr

This is the odd speedo drive from the early bikes. A pair of tangs engage with slots in the plate attached to the hub. A rudimentary rubber seal keeps road dirt our from the bearings.

Speedo drive 2 by graham.curtis, on Flickr

Looks a little odd with the screws of the drive plate showing but the design didn't last for long...

speedo drive 1 by graham.curtis, on Flickr

G

sarals · Post by **sarals** » Mon Jun 23, 2014 11:19 pm

I'm loving the detail, Graham!