Denso Alternator, how to fit mechanically

[Larry Zimmer]

A general comment regarding the stock system: keep ALL the connections in the charging circuit TOTALLY FREE of corrosion. (Applies to any system.) True, it won't run 14 volts at idle. But, then, your CBX won't run very long at idle anyhow!! (You'll be rebuilding more than the alternator.)

[512tr]

alternator coubling.jpg

This is the alternator coupling plates I put in, how much slippage there is at hard acceleration/deceleration is unknown, if any at all…. but I think it is much better than the OEM steel to steel coupling.

Some have expressed concern about particles in the oil from the wear of the fiber plate, on the other hand there will be steel particles in the oil from the OEM steel-to-steel wear witch I think is much worse, in addition there is fiber particles in the oil from the wet clutch wear… so I don’t worry that much…. But to be on the safe side I change oil/filter quite frequently.

The flywheel effect and the spinning torque that the OME alternator creates is a point, but I think few of us are able to feel the difference with the low mass alternator as the Denso.

Larry, the charging at idle was only to state that the charging is working well … Idling the CBX in general; the high heat generating air-cooled, carb’d, 6 cyl. engine, idle should be minimized to start up and short necessary stop in traffic, otherwise keep it moving.

My point is that the CBX OEM alternator is not “low output” for its purpose, if serviced properly and no critic to the Denso conversion

[Larry Zimmer]

Nice work on the clutch plates. Let us know, downstream, how it goes. With a good lap job on the iron plate and some reasonably hard friction material, I would think very little contamination to get into the oil.

[512tr]

Larry, will do....I believe and hope there will be no extraordinarily to report when I do more km on my CBX.

[Syscrush]

What is wrong with the OEM alternator except for the gear/clutch drive, which could easily be improved?

I took advice on this forum to upgrade the alternator to keep up with my electric heated vest and gloves.

I am also in the (lengthy and stalled) process of converting my bike to EFI, and the high pressure pump and 6 injectors put significant load on the charging system.

[CBX-tras]

Keep in mind that monitoring and calibration of engine temperature is critical with EFI on an air cooler motor.

The main reason most EFI motors are liquid cooled to keep the temp constant.

[RC 166]

As the mechanical part is pretty much covered by now, I feel it could be practical to include an electric charging schematics as well.

The shematics shows a Denso alternator rewired as per CBX-tras version to match the CBX color-coding. Well, we use a red charging wire instead of the correct red/white simply because it is near imposible to find small quantities of 2.5-4mm2 red/white wire off the shelf anywhere.


CBX-tras, I hope you don't mind me using your picture below.

Wiring 750 Alternator.jpg

My shematics proposal use a relay to provide the alternator with a healthy low resistance sensing of actual battery voltage. Normally this sensing is influenced by the contacs in the ignition switch and I think the relay help us to sense directly at the battery.
Furthermore I like to at least use recommended wire gauges for the 28 AMP’s the alternator may deliver at most, which is 2.5mm2 for wire lengths < 1m. I will try to use 4mm2 if I can find with small outer diameter.

Mind you, I have not tried this yet, so I welcome any comments or hints from this highly competent community.

CBX with Denso alternator charging circuit.jpg

[CBX-tras]

For the relatively short run from the alternator to the battery, 12 gauge (AWG) wire is sufficient. Anything larger is overkill and finding a TXL insulation is expensive. My wholesale supplier is at $0.54 per foot with a MOQ of 250 feet. IMO, not worth the trouble.

The relay is a good idea, can't hurt.

You have my blessings.

[RC 166]

Thanks, CBX-tras,

OK, if you guys who have tried it repeatedly over a number of years are happy with AWG 12 (3.3mm2), then I will also use AWG 12 (3.3mm2) which is right in the middle of my expected range for the charging wires.
Will AWG 12 (3.3mm2) wires get warm at all when charging a totally empty battery with a Denso?

I guess I am a little on the overkill side owning 2 daycruisers. All main cables from battery to switch and to heavier users are 6mm2 (AWG 9-ish).
But on a boat the cables tend to be long, 2-8m generally, and voltage drops come quickly as the cables get longer.

[CBX-tras]

FYI, I've been designing, fabricating and installing wiring harnesses for boats, cars, semi-trucks, and motorcycles for over 4 decades.
Many race cars, RV's, vintage automobiles and hot rods.
I was contracted by General Motors to develop the wiring in the COPO Camaro and private teams for the Drag-Pak Challengers.
I taught this very subject at a local college for 5 years.
You can trust my recommendations on wire, wiring, terminals, connections, looming, relays, batteries, etc.
A few of the projects I've worked on:

[Syscrush]

You're making me wish that I worked on stuff that you could take cool photos of like that AMX and Nomad!!!

On one hand, it's too bad there's no way to take photos of real-time ETF & FX market making software. On the other hand, they wouldn't be that cool even if I could. :)

[Dynamohum]

Nice Rambler ‘Nomad’.

[CBX-tras]

Actually a '60 Rambler, highly modified to resemble a Nomad in 3/4 scale. We also used a Chevy dashboard, sectioned to fit.
Hidden wiring, hidden brake lines, gas filler behind a motorized taillight, etc.
The car was considered for the Ridler Award at the Detroit Autorama, wins awards everywhere it's shown. Feature article in the Goodguy's Gazette.

Fabulous trim work by Willy's Workshop in Port Huron, MI.

[Jeff Bennetts]

Very cool and unique!

[Syscrush]

Actually a '60 Rambler, highly modified to resemble a Nomad in 3/4 scale. We also used a Chevy dashboard, sectioned to fit.

That's 10x better than a Nomad OR a Rambler.