Denso Alternator, how to fit mechanically

[daves79x]

The Australians also come up with a version, I have one here that I could never get to work. It's at least 30 years old. It uses an in-line festoon light bulb as added resistance, rather Flinstonian by todays standards.

Dave

[CBX-tras]

Peter, like you Stephen Jung liked the look of the denso for some of his highly modified CBX’s! The Euros were way ahead of us here in the states when it came to the amount of modified bikes early on. Stephen was the first that I know of that sold the alt conversion 20 some yrs ago, Tim’s then updated the design and sold them from his store. Others like JR sold them or offered them to their customers as upgrades during servicing their bikes.

Maybe JR or Dave can remember better than I?

The Jung conversion was basic, but it worked. Spliced wiring, screwed and glued sheet metal splash shield, drive adapter with a spacer, etc.
When I made my first few to get going, I made improvements to the Jung unit while re-designing and improving everything.
The biggest hurdle was rebuilding and testing used alternator cores. It was my intention to acquire new alternators directly from Denso. However, they couldn't sell to me as Kawasaki had paid for the tooling and is proprietary. The rep at Denso told me that even if he could sell them to me, the minimum order quantity was 144 (a pallet load) at about $100 each.
Do the math, at that point it didn't make a business case.
Other people blatantly copied my design that couldn't be patented, (I tried) eliminated things they thought weren't necessary, cutting corners and selling a product that wasn't tested.
Yes, I took Stephen's idea and improved on it as ours are doing right now with what I did. God Bless.

FWIW, I'll gladly sacrifice a weight penalty and aesthetics for a part that out-performs the stock item. The Denso alternators provide ample (see what I did there) power at idle and the entire RPM range. This energizes the ignition system to work as designed and can INCREASE the idle speed. Additionally, it wouldn't "flywheel" the motor like the stock one would if coupled directly by its rotating mass. This is another point not considered.

Your results may vary.

[RC 166]

JoeInTUS,
You are absolutely right, I forgot to include the regulator/rectifier in my comparison. So now the Denso got the upper hand as it already has a built-in rectifier/regulator. Now the conversion actually REDUCE weight off my CBX!

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[RC 166]

I have now designed a one piece drive hub with the correct length, so no spacer needed anymore. I started with 3 off as I had suitable material laying around for that. They are almost ready, just need to hand them over to the wire cutter to cut splines in them.

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It's amazing how much a small piece of steel round stock weighs. It is only Dia 66mm x L45.5mm.

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[RC 166]

Hi all,

Just got back my drive hubs from the wire cutter completed with splines.

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I also made a precision gauge to check the splines with

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The alternator-to-adaptor plate M8 x 65 screws got a blob welded on to keep them from rotating.
The adaptor plate-to-engine screws are Torx M6 x 20mm

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If I end up "producing" more of these parts, it will only be the mechanical parts and fasteners needed for the conversion. Users have to source the alternator and use o-rings from donor CBX / Denso OEM alternators (or buy new ones as necessary).

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[NobleHops]

Super cool!

[RC 166]

Thanks Nils,

These are the units any user would have to source + any electrical bits & skills

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[RC 166]

Thanks CBX-tras,

I personally like the Denso design more than OEM. It looks more "high tech" although it could be an inch shorter.
I will make a nicer end cap in alu though. But then my whole bike will be something else with Kawasaki ZX-9R front end, custom top yoke, ZX-9R rear wheel, Yamaha FZR 1000 swing arm, Ohlins twin shocks etc... I will soon start a thread on it under "Project Threads"

Looking forward to it!

Hi all,

I just started my build thread over here: viewtopic.php?f=102&t=12689

[CBX-tras]

If you use the alternator that's black, that came on (typically) the ZRX-1100 and 1200, there is less trouble machining the adapter plate. Same output.

Kawasaki p/n 21001-1104, 21001-1134, 21001-1150.

Good luck and keep going.

[CBX-tras]

Additionally, (at least on ProLink models) it allows the opportunity to do some rewiring with better fuses.

Shown here from 15 years ago, where the rectifier used to be, I have a separate fuse protecting the bike main circuit, the alternator by itself, a spare, and relocate the 4 circuits that used to be in the upper fork tree.

Another more recent bike that has a 35A micro relay for the Ignitech, electronic turn signal flasher and 35A micro relay for the rest of the bike. This eliminates un-necessary wiring and shortens the path of power while removing the load through switches.

[RC 166]

CBX-tras,

Thank you for the additional info on re-wiring. Do you have updated schematics with these improvements?

[CBX-tras]

CBX-tras,

Thank you for the additional info on re-wiring. Do you have updated schematics with these improvements?

Sorry no, just simple wiring done on the fly with materials on hand.

There are many ways to do it, basic micro relay wiring.

[Jeff Bennetts]

That really looks tidy JR.

[RC 166]

Nice, clean wiring job CBX-tras!

OK, will do the same when I get to that part. Have done lot of cars, boats, mc sofar. Also cleaned up crap wiring in my CNC-systems (lot of work)...