Honda CB750K Cafe Racer project about to start with a monoshock??

rohalloran

Member
Anyone who has put one of these SOHC CB750 engines in will understand how hard this was! 90 minutes but managed to get it in with minimal scratches..



 

irk miller

You've been mostly-dead all day.
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Did you explain somewhere the story with those carb flanges? Were they already on the engine?
 

rohalloran

Member
irk miller said:
Did you explain somewhere the story with those carb flanges? Were they already on the engine?
Yes when I got the bike these were on it and they defo are not coming off. The bike had Bandit 600 carbs fitted so hopefully it will run with minimal tuning.
 

irk miller

You've been mostly-dead all day.
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You should have three ports on a CB750 oil tank. The third for a vent.

The oil is gravity fed, so for one bottom port, it will work, but the second port should be on top, unless you have a straw to push oil above the tank level. The third port should be at the top of the oil tank and connected to the vent on the back of the crankcase.

 

rohalloran

Member
irk miller thanks for this. Yes I will have the 3 ports. This was mainly used for sizing purposes to see how it would fit.
 

rohalloran

Member
Been a while since I last posted. But finally getting near the finish line. (I hope...)

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 straight 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.
 

rohalloran

Member
These guys know their Hondas and here it is listed under the model also:

https://www.davidsilverspares.co.uk/CB750K7-FOUR-1977/

Sonreir said:
Not seen one like that before. I suspect it's not the correct unit for your bike.
 

rohalloran

Member
Interesting reply over on the SOHC forum

"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."
 

rohalloran

Member
Been busy the last few weeks!


Cleaned and powdercoated


Wiring mess to clean up


Front end fitted


Clocks look good!


Callipers fitted!


Exhausts painted and ready for wrapping!

Just wait on the clips-ons to finish off the front end..
 

rohalloran

Member
I'm about to stat on wiring aftermarket handlebar switches into the new wiring loom. Needless to say, it is not plug-n-play so I am going to cut all the connectors and fit with new SuperSeal connectors. Has anyone done this or is there any advice anyone would like to share before I start? I have a fill colour wire diagram so that will certainly help.
 
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