Author Topic: Any reason for this specific bolt for the brake arm?  (Read 1547 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

Offline McCabe-Thiele (Ted)

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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 CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

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 , Yamaha fazer 600, Yamaha XT250, BmwR80 , HondaVT1300, Royal Alloy GT125.

Offline McCabe-Thiele (Ted)

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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 CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

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 , Yamaha fazer 600, Yamaha XT250, BmwR80 , HondaVT1300, Royal Alloy GT125.

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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