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Author Topic: 77K CB 750 Regulator Rectifier Upgrade query??  (Read 138 times)

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Offline rohalloran

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77K CB 750 Regulator Rectifier Upgrade query??
« on: September 18, 2019, 10:58:50 am »
I have searched the forum looking for an answer to my query but to no avail. I bought this regulator rectifier from Dave Silvers for my 1977 CB750K7.

https://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_31700333RR24/

The block connection is stright forward but the other wires that go to the regulator are confusing me and the instructions that came with the part are useless!

My old regulator has 3 wires; black, white and green. But this just has one black/red wire with a split connection on it?

https://www.davidsilverspares.co.uk/graphics/parts/31700333RR24_large.jpg

Any advice on what goes where?

Thanks in advance.

Offline Bodi

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Re: 77K CB 750 Regulator Rectifier Upgrade query??
« Reply #1 on: September 18, 2019, 11:15:49 am »
My opinion: that is a shunt regulator and not the ideal choice for your bike. These run the alternator at 100% power 100% of the time and almost all waste excess power to ground. Not a worrying horsepower stealer, full alternator load takes maybe 1/3 horsepower from the engine. But the alternator wasn't designed for full zot all the time, and may overheat.
This type of regulator is normal on permanent magnet alternator bikes.
A field control regulator varying alternator output according to load is what it was designed for, there are several aftermarket ones available.
To use this one, the black wire from your reg/rect has to be connected to the black and white wires on the original regulator. You take those wires off the regulator and plug in the spades on the new one. If any metal shows at those connections, tape over them: the connector metal must not contact the frame or anything metal attached to the frame. The green wire from the old regulator can be left loose.

Offline rohalloran

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Re: 77K CB 750 Regulator Rectifier Upgrade query??
« Reply #2 on: September 18, 2019, 12:14:47 pm »
Bodi many thanks for the reply. Are there any solid-state regulator rectifiers you would recommend instead?

My opinion: that is a shunt regulator and not the ideal choice for your bike. These run the alternator at 100% power 100% of the time and almost all waste excess power to ground. Not a worrying horsepower stealer, full alternator load takes maybe 1/3 horsepower from the engine. But the alternator wasn't designed for full zot all the time, and may overheat.
This type of regulator is normal on permanent magnet alternator bikes.
A field control regulator varying alternator output according to load is what it was designed for, there are several aftermarket ones available.
To use this one, the black wire from your reg/rect has to be connected to the black and white wires on the original regulator. You take those wires off the regulator and plug in the spades on the new one. If any metal shows at those connections, tape over them: the connector metal must not contact the frame or anything metal attached to the frame. The green wire from the old regulator can be left loose.

Offline Bankerdanny

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Re: 77K CB 750 Regulator Rectifier Upgrade query??
« Reply #3 on: September 18, 2019, 03:34:23 pm »
I have searched the forum looking for an answer to my query but to no avail. I bought this regulator rectifier from Dave Silvers for my 1977 CB750K7.

https://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_31700333RR24/

The block connection is stright forward but the other wires that go to the regulator are confusing me and the instructions that came with the part are useless!

My old regulator has 3 wires; black, white and green. But this just has one black/red wire with a split connection on it?

https://www.davidsilverspares.co.uk/graphics/parts/31700333RR24_large.jpg

Any advice on what goes where?

Thanks in advance.

I used the Ricks Motorsports unit on my 550. It took 20 minutes to install in the driveway with simple tools:

https://ricksmotorsportelectrics.com/results/
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki 80 (K11 probably, it's been 30 years), '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline rohalloran

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Re: 77K CB 750 Regulator Rectifier Upgrade query??
« Reply #4 on: September 19, 2019, 12:25:46 am »
I see they have one specific for Lithium batteries which I hope to run:

https://ricksmotorsportelectrics.com/Lithium-Ion-Battery-Compatible-Rectifier-Regulator-14_100



I have searched the forum looking for an answer to my query but to no avail. I bought this regulator rectifier from Dave Silvers for my 1977 CB750K7.

https://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_31700333RR24/

The block connection is stright forward but the other wires that go to the regulator are confusing me and the instructions that came with the part are useless!

My old regulator has 3 wires; black, white and green. But this just has one black/red wire with a split connection on it?

https://www.davidsilverspares.co.uk/graphics/parts/31700333RR24_large.jpg

Any advice on what goes where?

Thanks in advance.

I used the Ricks Motorsports unit on my 550. It took 20 minutes to install in the driveway with simple tools:

https://ricksmotorsportelectrics.com/results/

Offline rohalloran

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Re: 77K CB 750 Regulator Rectifier Upgrade query??
« Reply #5 on: September 20, 2019, 07:30:19 am »
Anyone any experience with lithium batteries and upgrading their regulator rectifier?

 

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