1977 Bonneville resto

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Ran into snag with rear master cylinder only fits one way. take it off try again, thought I finally had it but couldnt adjust brake pedal. tthink I have it now. BBEER
 
Moved to Norfolk Va last July only able to work on it since Covid will send new pictures. will have to revisit rear master cylinder it rubs on tire.
 
rear master cylinder it rubs on tire.
same problem with my '78. turned out the brand/model of tire was JUST A BIT too wide.
The original master didn't rub
The width number moulded on a tyre wall is not the overall width.

'77 twins were fitted originally with either Dunlop K70 or Avon SM Mk.2 4.00x18 rear; their overall widths are, respectively:-

. "4.17 inches" (106 mm) on a 2.15 rim width (WM3 equivalent) (source Buy Dunlop K70 Tires From Your Local Dealer | Dunlop Motorcycle and scroll down to "SPEC CHART");

. 111 mm on a 2.50 rim (WM4 equivalent) (source SAFETY MILEAGE A MKII and scroll down to "Tyre specifications");

... otoh, all 'modern' tyres are wider overall - e.g. an Avon AM26 Roadrider 4.00x18 is 116 mm on a 2.50 rim (source ROADRIDER MKII and scroll down similarly); ime, although Roadriders are wider overall than older-design tyres, they are still overall-narrower than some other 'modern' tyres makes.
 
Think I found the problem. I have a 76 manual and parts catalog. It shows 2 spacers for the rear master cylinder to frame. in 78 parts catalog it only shows a thin washer. now to remove rear master "again" and try without spacers. wish me luck.
 

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