Denso Alternator, how to fit mechanically


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RC 166
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Denso Alternator, how to fit mechanically

Post by RC 166 »

Hi everyone,

Long time no see... I am now in the process of rebuilding a dismantled CBX -79. As the OEM alternator have a toasted rotor, i will not waste time and money trying to fix it. Instead I will do what many of you alreade have done- install a Denso alternator from a Kawasaki ZX-9R -94 that I bought years ago. I have read many of the alternator conversion threads here but so far not found enough info how to DIY mechanically from scratch (not only buy a kit from TIM's or similar). A question about my photo attachments below: They are all rotated 90 deg. anti clock wise. Why is that?

This is the alternator I have
20230221_110553.jpg
The first problem to solve is to make the drive hub to fit the CBX shafts splines. Lyckily the Denso splines have a major diameter that is the same as the OEM splines' minor diameter. I have a friend that runs a wire electro cutting business. We copied the OEM splines and re-cut the Denso hub. Result! The Denso hub now slides snugly onto the CBX 19-spline shaft.
20230221_111026.jpg

This is the modified Denso hub that now fit the CBX drive shaft
20230328_153108.jpg

OK, now the hub slides on perfectly but does not reach the drive shafts 25 mm shoulder since it hits a corner in the crank case.
20230329_141239.jpg


I had to make a spacer sleeve with OD=25.00mm, ID=20.00mm and L=12.00mm and slide it on against the drive shafts 25mm shoulder prior to fitting the Denso Drive hub.
20230329_134618.jpg
The Denso drive hub with L=12.0mm spacer sleeve under it in situ. Now there is some space between the hub and crank case
20230329_141447.jpg
Next, I have to order new Denso rubber cushions and install them between the Denso drive hub and the alternators driven hub.
Then when I push the alternator onto the drive hub, I can measure the gap between the alternator and crank case. The reulting measure will determine the thickness of the adaptor plate I need to make between the Denso alterntor and the CBX crank case. I own a one-man CNC-shop, so I can make lots of CNC-machined parts in house.

I have a question about this adapter plate: When you fit those ready made kits onto the crank case, do you feel that you squeeze the rubber cushions somewhat or is there some axial end play?
/ Peter
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Own a one-man CNC shop, Building a CBX '79 with ZX-9R suspension and lots of nice custom CNC parts...
/ Peter

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Re: Denso Alternator, how to fit mechanically

Post by CBX-tras »

One of the reasons that I couldn't patent my conversions is that any machinist could reproduce what I designed.

All I will say is that an alternator will make electricity in either direction of rotation.

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Re: Denso Alternator, how to fit mechanically

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CBX-tras,
You mean something like this? Body flipped inwards and belt driven? Naa, I think that would be less practical than the "normal" Denso approach.
But I like the engineering though, and I bet there are AMPs in that one! 8)
DSC07088.JPG
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Own a one-man CNC shop, Building a CBX '79 with ZX-9R suspension and lots of nice custom CNC parts...
/ Peter

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Re: Denso Alternator, how to fit mechanically

Post by CBX-tras »

No. More like one of these that I built, a 10 minute installation. Plug and play:
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Re: Denso Alternator, how to fit mechanically

Post by Larry Zimmer »

[But I like the engineering though, ] Gotta give a 'ditto' on this. If he carries a cooling fan he can power his camp site! :) :)
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Re: Denso Alternator, how to fit mechanically

Post by RC 166 »

CBX-tras,
Very nice installations. I have read all about your conversion kits and I think yours were the best. My aim is to have mine to look and work like the one in your top pic. A question about the shiny "ceramic" version: Did you send the shell in for a certain surface treatment or is it a "rattle can" finish?

BTW, my last reply actually adressed the last sentence in your earlier post about the direction of rotation.
"All I will say is that an alternator will make electricity in either direction of rotation."
Own a one-man CNC shop, Building a CBX '79 with ZX-9R suspension and lots of nice custom CNC parts...
/ Peter

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Re: Denso Alternator, how to fit mechanically

Post by CBX-tras »

The ceramic coating is a process commonly known as "Jet Hot".
The bare case is media blasted, a liquid coating is applied and baked, then vibration tumbled in a vat of ceramic BB's until the shiny surface appears.

It's an aluminum product that can be hand polished when/if needed with an aluminum polish. I prefer "Purple Polish" for best results.

The material can be applied to steel, stainless steel, brass, blasted chrome and aluminum. The harder the material, the better the finish.

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Re: Denso Alternator, how to fit mechanically

Post by RC 166 »

Thanks for the info!
I will look Into that as it is the finish I like most. Will do that on the adapter plate as well.

What about the rubber cushions compression/end play?

I guess the adapter plate should have an oil splash shield like the OEM alternator to keep oil from entering the crank case vent. Have not seen any shield on most kits offered on Internet. How do they cope with any oil spray.
Own a one-man CNC shop, Building a CBX '79 with ZX-9R suspension and lots of nice custom CNC parts...
/ Peter

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Re: Denso Alternator, how to fit mechanically

Post by CBX-tras »

RC 166 wrote:
Tue Apr 04, 2023 6:17 pm
Thanks for the info!
I will look Into that as it is the finish I like most. Will do that on the adapter plate as well.

What about the rubber cushions compression/end play?
Full engagement, no pressure.

I guess the adapter plate should have an oil splash shield like the OEM alternator to keep oil from entering the crank case vent. Have not seen any shield on most kits offered on Internet. How do they cope with any oil spray.

Splash shield necessary or the oil can be sprayed directly into the breather tube and exit the motor. How do they cope? They don't. Seems like most ppl that copied my design missed this critical feature. I never understood why either. Just look at the stock alternator and see how/why Honda did it.

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Re: Denso Alternator, how to fit mechanically

Post by RC 166 »

Thanks CBX-tras,

That's the logic answer I expected. Will make adapter plate to result in no play/no press.

Yeah, the stock design tells it all, right? Dont think they "missed it". Shortcuts you know....
Only draw back is that I need a huge billet to start with as the shield protrudes 30mm into the crank case. I dont trust welding something to the inside of the plate.
Own a one-man CNC shop, Building a CBX '79 with ZX-9R suspension and lots of nice custom CNC parts...
/ Peter

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Re: Denso Alternator, how to fit mechanically

Post by CBX-tras »

The plate should be thick enough to do a mechanical fastening if you're not comfortable with welding.
Others have. But, not me.

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Re: Denso Alternator, how to fit mechanically

Post by RC 166 »

OK,

I will either bite the bullet and do the plate in one piece from a large billet or figure out the best way to securely attach a separate shield on inside.

20230221_110529.jpg
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Own a one-man CNC shop, Building a CBX '79 with ZX-9R suspension and lots of nice custom CNC parts...
/ Peter

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Re: Denso Alternator, how to fit mechanically

Post by CBX-tras »

I found that the most cost effective way to manufacture the adapter plate for production was to weld the splash shield to the plate.

Other ppl saw it as not necessary and didn't attempt to minimize the oil spray, in any form.

Keep going.

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Re: Denso Alternator, how to fit mechanically

Post by RC 166 »

I agree, for production in quantities I guess a 2 piece solution is a must. Aluminium prices are sky high now. No-one wants to pay...
However when making a one-off for myself it is just a matter of paying more for a larger billet or working more doing 2 parts + welding or whatever.
Own a one-man CNC shop, Building a CBX '79 with ZX-9R suspension and lots of nice custom CNC parts...
/ Peter

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Re: Denso Alternator, how to fit mechanically

Post by CBX-tras »

If money isn't a concern.............it'll be a beautiful part.

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