Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: Ken4004 on November 02, 2025, 04:07:48 PM

Title: Regulator rectifier position
Post by: Ken4004 on November 02, 2025, 04:07:48 PM
Many years ago I had a Cb 400 f2 and I bought it on eBay , the previous owner had fitted the updated regulator rectifier on top of the battery cover as per photo attached.

When I owned my Z1000 I fitted an updated regulator rectifier on the frame with one bolt but soon noticed that it got fairly hot when in use so I made a 1/4 thick square of aluminium the same size and mounted the regulator on to it this acted as a very efficient heat sink which kept it nice and cool.
I just wondered what is the preferred way of mounting the regulator/rectifier on the 400 4 so if anyone has any ideas or photos that would be great.

Many thanks regards Ken
Title: Re: Regulator rectifier position
Post by: Bryanj on November 02, 2025, 05:36:35 PM
Somewhere in a good airflow is best
Title: Re: Regulator rectifier position
Post by: TrickyMicky on November 02, 2025, 06:21:38 PM
When I fitted mine, the frame lug which holds the rectifier on was on its last legs, so I fabricated a mounting plate out of an old brass window hinge(!), and mounted the new unit where the original regulator was. The wires were long enough to reach across, and I reckoned it would get the same amount of airflow behind the left cover as the right one. This was in January 2016, and so far so good.
Title: Re: Regulator rectifier position
Post by: Ken4004 on November 02, 2025, 07:07:57 PM
Thanks Mickey

I’ll try and fit it on the original lug which is not a complete lug it’s 3/4 of a lug more like un upside down hook, I’ll try to see if I can find a photo of the original frame to see what the mounting point should look like.
Title: Re: Regulator rectifier position
Post by: Ken4004 on November 02, 2025, 07:31:45 PM
I think this is the lug for mounting the regulator so as I described
Title: Re: Regulator rectifier position
Post by: exvalvesetdabbler on November 03, 2025, 04:58:24 PM
On the OEM rectifier there is a stud attached that has a M8 thread and a flat machined on two sides that should fit in the 'hook'.

Regards
Dave
Title: Re: Regulator rectifier position
Post by: Bryanj on November 03, 2025, 05:53:24 PM
Yup, thats the rectifyer mount, regulator mounts to electric panel as i remember
Title: Re: Regulator rectifier position
Post by: exvalvesetdabbler on November 03, 2025, 07:22:37 PM
Rectifier





Title: Re: Regulator rectifier position
Post by: exvalvesetdabbler on November 03, 2025, 07:25:21 PM
Regulator
[attachimg=1]
Title: Re: Regulator rectifier position
Post by: Ken4004 on November 03, 2025, 08:55:52 PM
Thanks for the photos guys , when I stripped the bike down I took a lot of photos but there’s always something you miss so many thanks again
Title: Re: Regulator rectifier position
Post by: Bryanj on November 03, 2025, 09:13:06 PM
The 400 regulator is different from all the other fours as the spade connectors face like in picture and not straight out of the back, presumably due to space constraints
Title: Re: Regulator rectifier position
Post by: TrickyMicky on November 04, 2025, 08:33:20 AM
Ken, if you use the original lug, examine it carefully for signs of fracturing around the fixing hole/ 'U' bend!!  Mine was on its last legs with what looked like a vibration fracture as it's not a very thick piece of metal. That's why I fitted my new combined unit where the original regulator was.
Title: Re: Regulator rectifier position
Post by: Ken4004 on November 04, 2025, 01:48:03 PM
Ok thanks for the heads up Mickey