Author Topic: Any reason for this specific bolt for the brake arm?  (Read 422 times)

Offline alexdecker

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Any reason for this specific bolt for the brake arm?
« on: February 25, 2024, 04:43:39 PM »
Hi all

Replacing some parts for the rear brake of my 550F from 1977. Just got all the parts from CMS and discovered too late that I forgot this part, and attaches the brake arm to the frame:

https://www.cmsnl.com/honda-cb550f2-super-sport-550-four-1977-european-direct-sales_model17122/bolt-stopper-arm_90133286000/

Would there be anything wrong with using a normal bolt and riding with that until my next part order? Feel like it’s a little much doing a part order for just one bolt.

Why does this need a special bolt to begin with? Just to be able to lock it with a pin? Seems to me I could just use a regular bolt the same thickness as the thick part of the original bolt? But as usual, I might be missing the bigger picture, so wanted to hear your opinion in here  :)

- Alex

Offline Bryanj

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Re: Any reason for this specific bolt for the brake arm?
« Reply #1 on: February 25, 2024, 05:29:09 PM »
Its a shouldered bolt so that when the nut is done up tight it can still allow the torsion arm to pivot.
You could probably get away with a collar of the right dimensions and a nylock nut

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Re: Any reason for this specific bolt for the brake arm?
« Reply #2 on: February 25, 2024, 06:30:50 PM »
I agree with Bryan for a short term solution, personally I see a split pin as an essential long term safety feature.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline davidcumbria

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Re: Any reason for this specific bolt for the brake arm?
« Reply #3 on: February 25, 2024, 06:43:27 PM »
If it’s like my 550 k1 it is specially shaped to locate in brake shoe holder. Also it needs a spring clip not a split pin making rear wheel removal easier. Here is a photo of the bolt. You might want to look at your backplate because a hex head wouldn’t fit - but the 500f might be different.

https://www.cmsnl.com/honda-cb550-k1-four-1975-usa_model466/bolt-rear-brake_90127323000/
« Last Edit: February 25, 2024, 06:46:17 PM by davidcumbria »
500/4 in 79. No bikes for 30 years. 750/4 in 2013, 550/4 in 2023. Also own  R1100GS, RD350LC YPVS , Triumph Street Triple, Yamaha XT250

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Re: Any reason for this specific bolt for the brake arm?
« Reply #4 on: February 25, 2024, 06:46:26 PM »
I think were talking about two different pivots in the rear brakes.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline davidcumbria

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Re: Any reason for this specific bolt for the brake arm?
« Reply #5 on: February 25, 2024, 09:32:11 PM »
Yes I’ve highlighted the brake end not the frame end.
500/4 in 79. No bikes for 30 years. 750/4 in 2013, 550/4 in 2023. Also own  R1100GS, RD350LC YPVS , Triumph Street Triple, Yamaha XT250

Offline alexdecker

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Re: Any reason for this specific bolt for the brake arm?
« Reply #6 on: February 26, 2024, 05:44:14 AM »
Thanks guys. I will try and do an intermittent solution until I make my next part order, and save a bit of money and the environment then :)

Offline Bryanj

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Re: Any reason for this specific bolt for the brake arm?
« Reply #7 on: February 26, 2024, 07:36:47 AM »
Try your local dealer, its probaably still available

 

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