Snakeoil wrote:Thanks Fred and LM. This is what I was looking for. I suspected it was not the right bolt and I did notice that it had a special part number in the book. My intial thought is it was a hardened bolt.FAST FRED wrote:Rob, the bolt does have a special part number amd is kind of a dowel bolt that has been sized to fit the bushing properly' This pivot allows the brake backing plate to float as the brake linings wear ( I think). Fast Fred
There is no bushing for the lower hole so it appears that it should snug up properly, which it doesn't so this bolt, although a correct period bolt, is not the right length. This one actually cannot be trimmed because the threaded portion ending too soon is also a problem. No spacers shown in the parts book so I'll just have install the correct bolt size. I can turn a small bushing to emulate the shouldered portion of the upper bolt.
The entire assembly seems to be a contradiction of designs. The brake plate is fixed, yet the brace has a bushing on the top to allow movement and none on the bottom thus preventing movement. I suspect they let a team design this one. Oh well.
regards,
Rob
'67 CL77 front brake brace bolts
Re: It moves. it movesYa will find that the bolts at each end have keepers to keep them from coming loose. ......lm
Rob - I'm a mechanical engineer by trade, 30 years. Working on Hondas since I was 16. With almost no exception, the fasteners, washers, spacers, etc. used by Honda make sense if you ponder it long enough. You are obviously very detail-oriented like me, and are smart to question things that may have been altered by previous owners and "mechanics" in the intervening 40 years since these bikes were new. To a certain extent, our lives depend on it. One of the things that make these bikes so interesting to me is trying to get inside the designer's head. Your brake arm is a good example. I think the design intent on the wheel end is for a firm connection, with the "tongue" washer preventing the bolt from loosening. I'm sure you've noticed that the common bolts on these bikes had rolled threads that makes the shank diameter slightly less than the major diameter of the threads. The correct bolt has cut threads so the shank can make a closer fit with the hole in the stopper arm. The inside diameters of any stopper arm hole never bear on a threaded portion of a bolt. The spacer on the fork end is probably to allow for slight misalignment so that tightening of the bolt doesn't introduce unintended stresses on the arm - its designed to be in tension only. Again, cut threads, unthreaded within the spacer. Now - Did you get my PM? Let's talk tools!
Chuck Thanks for the detailed response, Chuck. I'm with you on everything you said because I work as an engineer, as well. My machinist background is where it all started years ago.
The rear brace must be free to move because of the requirement to adjust the chain regularly. I suspect that design might have been carried over to the front brace. At first I thought that the bushing at the top was to provide more surface area and reduce potential wear on the bolt. Better to saw thru the bushing than the bolt. But the lower portion has nothing but a hole and a bolt to go thru it. I guess we'd have to talk to the engineer that came up with the design. I am very cautious about how I put bikes together. I've crashed on the track so I know how nasty it can get. The thought of a major failure at speed send chills up my spine. What makes me chuckle is all the protective gear we wear when we ride motorcycles. Yet somebody riding a bicycle out in traffic wears designer spandex and a pool toy as a helmet. I've often thought about that as I've ridden down hill and my speedo says 50mph and I'm wearing the non-designer spandex and no helmet. I know I'm gonna get that call some day from the village that wants their idiot back. regards, Rob
The rear is movable cause the swing arm moves Up/Down which changes the angle of pivot. ...lm
Ya say Adjustment.
Well check the degree of swing at the front of the SA and figure the degree of movement. I'd say it has to do with keeping the chain in a sort of tension as the SA goes up/down. It has to do with the angle of the SA to the level of the drive sprocket. ..............lm
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