Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: exvalvesetdabbler on June 23, 2025, 07:30:25 PM

Title: Replacement Horn
Post by: exvalvesetdabbler on June 23, 2025, 07:30:25 PM
I have had enough of hitting the horn to make it work so I sourced a replacement from a well known Chinese auction site.


[attachimg=1]

[attachimg=2]

The only difference is 13 mm bracket hole with the old one and 12 mm with the new one.  I just need to machine up a washer/collar to adapt it to the old bracket.  OD is the same size so hopefully the plastic cover will pop on ok.

Regards
Dave

Title: Re: Replacement Horn
Post by: Athame57 on June 23, 2025, 08:03:25 PM
What is this horn cover? I've yet to see one. 
Title: Re: Replacement Horn
Post by: exvalvesetdabbler on June 23, 2025, 09:28:24 PM
The horn cover is just a decorative bit of plastic that is pressed on.  The plastic hardens so usually need to warm it up with a heat gun so it comes off easily without splitting.

[attachimg=1]
[attachimg=2]

Regards
Dave
Title: Re: Replacement Horn
Post by: exvalvesetdabbler on June 24, 2025, 02:53:13 PM
I machined up a shouldered washer from some 20mm SS round bar to couple the new horn to the old bracket.

[attachimg=1]  [attachimg=2]

[attachimg=3]

Just need to finish painting the bracket now.

Regards
Dave



Title: Re: Replacement Horn
Post by: Laverda Dave on June 24, 2025, 03:03:51 PM
Nice job Dave. Everyone should have a lathe in the workshop, fantastic bit of kit and so useful for so many things.
Title: Re: Replacement Horn
Post by: exvalvesetdabbler on June 24, 2025, 03:29:49 PM
Nice job Dave. Everyone should have a lathe in the workshop, fantastic bit of kit and so useful for so many things.

At school, metalwork was one of the subjects taught alongside technical drawing.  We had 3 Colchester bantams and a Boxford AUD alongside all the other metal working kit.  Most of it was sponsored by a local engineering firm that made machine tools, taps & dies etc.  Not sure if schoolkids these days would be let loose with such dangerous tools.  Oil fires were a regular occurrence when the whole class, towards the end of the lesson, was dropping red hot metal into a pot of oil to blue the metal.

Regards
Dave.
Title: Re: Replacement Horn
Post by: Mikep328 on June 24, 2025, 06:15:14 PM
Yep, times have changed.  Things that were totally normal/of no concern at all hazard-wise to us back then are now "shockingly dangerous!"

re the replacement horn - is it louder than a (properly working) oem horn?  My original horn works fine but on the road I think the only person that would hear it is me.
Title: Re: Replacement Horn
Post by: exvalvesetdabbler on June 24, 2025, 06:56:22 PM
It has the same specs 12V 3A 105db so is reasonably loud but it is never going to compete with modern cars that have two installed.  There are others that are louder but draw 5A.  Without knowing the switch rating, I wouldn't go any more than the OEM version without fitting a relay.

I just wanted something that works reliably and doesn't look too out of place.

Regards
Dave.
Title: Re: Replacement Horn
Post by: exvalvesetdabbler on June 25, 2025, 04:42:19 PM
Sprayed the front cone with a bit of wheel silver paint that I had laying around.

Not original but a functional necessity.

It fits.  Bit of a tight fit getting the cover back on, had to lube it up with some silicone grease and warm up the cover with the heat gun.  A good firm press and it popped in.

[attachimg=1]

[attachimg=2]

Regards
Dave
Title: Re: Replacement Horn
Post by: McCabe-Thiele (Ted) on June 25, 2025, 05:53:43 PM
Great thread, I never realised how interesting a horn replacement thread could be, more than good luck that the plastic cover fitted.

PS I'm not being sarcastic either.
Title: Re: Replacement Horn
Post by: Athame57 on June 25, 2025, 06:25:47 PM
I want one of those horns that sound like a horse!  ;D yeee ha!
Title: Re: Replacement Horn
Post by: exvalvesetdabbler on June 25, 2025, 06:41:17 PM
Glad it was of interest.

I retired from a high pressure job last September that had taken over my life.  Now that I have more time on my hands, I thought it was payback time to put something back into the community that had helped me out over the years, this forum and many others.  I'm just posting solutions to the problems every day bike tinkerer's  face in the hope that the info will be of use to someone when I'm long gone.

Regards
Dave
Title: Re: Replacement Horn
Post by: exvalvesetdabbler on June 25, 2025, 06:53:27 PM
Great thread, I never realised how interesting a horn replacement thread could be, more than good luck that the plastic cover fitted.

PS I'm not being sarcastic either.

The horn is a 'standard' 90 mm so there's lots out there.  The tricky bit was finding one with the nut that attaches it to the bracket. A lot of the cheapo ones are riveted so would be stuck with whatever bracket it came with. This one was around £8 so worth a punt.

Regards
Dave
Title: Re: Replacement Horn
Post by: SeanFD on July 04, 2025, 11:20:23 AM
Dave,

I need a horn also. Can you post a link to the one you bought?

Ta.
Title: Re: Replacement Horn
Post by: exvalvesetdabbler on July 04, 2025, 12:07:04 PM
Here it is

https://www.aliexpress.com/item/1005008539225760.html

Regards
Dave
Title: Re: Replacement Horn
Post by: SeanFD on July 04, 2025, 12:31:58 PM
Great, thank you.

Just ordered one; £2,72 and free postage!