Improved Alternator for 860GT

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Mayor08
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Improved Alternator for 860GT

Post by Mayor08 »

I have an early 1975 860GT and am interested to upgrade the stock 150w alternator to the more powerful 200w alternator. Why? I plan to add the Silent-Hektik electronic ignition and this was suggested to me by an authority on these bikes having restored/serviced these twins for decades. He did make a recommendation for a 200w upgrade but am looking for other options and opinions.

Doing some searching I found a site that recommended for a new components...

Rotor: RO92 - http://www.electrexworld.co.uk/acatalog/RO92.html
Stator: G92 - Generator http://www.electrexworld.co.uk/acatalog/G92.html

Has anyone here had experience with either of these items or any others for upgrading the charging system on the early 860GT?
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Re: Improved Alternator for 860GT

Post by jockduck »

I have no experience in upgrading my early 860GT because I have not had any problems with its charging even when used with the headlight on all the time, I have a rebuilt ducati ignition stator that has been very reliable and the added plus of being self generating. I understand the desire to boost the charging to cope with a new ignition system or you end up like the 750 roundcases, those items you attached look similar to the 200w system, I have a ducati 200w system on my GTS and think its wonderful. You will also have to change the regulator.
Jock
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Re: Improved Alternator for 860GT

Post by joepagejr »

This is what I did to my 860. Basically anything up to 300 watts should fit inside the cover. With the recess in the rotor that flat washer that folds over the flat on the nut was proving to be difficult to install correctly, so I got a metric "shaft nut" with star washer. There is an internal diameter tooth on the washer to fit in the key seat to hold it in place, then with spanner tighten the nut down, and once an external tooth lines up with a slot in the nut fold it down and it's locked in place.

I bought this particular regulator/rectifier: http://www.electrosport.com/street-bike ... ifier.html
The wiring instructions say to directly connect the negative lead to the negative battery terminal, but I had some firing issues out of my Lucas Rita ignition directly after installation, so I just connected the negative lead to the frame and the problem went away.

Hope this helps, mayor08.
Attachments
shaft nut washer.jpg
alternator.jpg
1975 Ducati 860 GT - 850589
2002 Ducati ST4s
Mayor08
Cucciolo - the Lil Pup
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Re: Improved Alternator for 860GT

Post by Mayor08 »

joepagerjr- good advice with the installation and I was on the electrosport website the other day looking at that regulator/rectifier. I heard back from electrexworld and they said the RO93 & G93 are correct for my bike but their items are rated at a 150w output. They might be better made but I was still looking for a stronger output what did you use for a stator? And is that the stock rotor you're using? How many watts is the bike putting out with this setup?
joepagejr
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Re: Improved Alternator for 860GT

Post by joepagejr »

My brother gave me the stator and rotor and he told me they were from a SS Darmah. The SS Darmah is rated to put out 200 Watts. Both the stator and rotor are wider than the original stock 860 GT parts, which is why I have the different fasteners on the crankshaft to secure it in place. As I mentioned before, you can get up to a 300 watt single phase setup inside the cover of an 860. My brother has a 300 watt setup off a 94 888 on his 860 (he's got a pretty neat ignition setup). Hope this helps.
1975 Ducati 860 GT - 850589
2002 Ducati ST4s
75860GT
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Re: Improved Alternator for 860GT

Post by 75860GT »

I know this is an old thread but I thought I'd post my solution as it doesn't seem to be covered.

My 860 GT had the very skinny rotor / stator combo that seems to be the same as the earlier 750

I got a stator from 98' or earlier Ducati 916, which fit perfectly in the case and doubles the width of the stator.
[img]https://i.imgur.com/zTaEdK9.jpeg[img]


And the rotor im not exactly sure what its from but it was advertised for a 1991-1998 Ducati 750 SS / SC It is aprrox 38mm deep, which seems to bethe same size or a bit wider than the ST2 rotor.

[img]https://i.imgur.com/a0vQ0UK.jpeg/[img]
[img]https://i.imgur.com/mzvc6Nw.jpeg/[img]

Originaly I bought a RO92 which was advertised to to fit but was far to deep as it came in contact with the alternator case and oil pump. Here it is compared to the 750 SS Rotor.

[img]https://i.imgur.com/SGNFPmw.jpeg/[img]

The reason i'm doing this is I put in a motogadget mo.unit blue and new lithium battery and rectifier and want to make sure i dont starve anything

I haven't tested the output but everything physically fits, it should output at least 200w or more. Maybe someone here can identify the parts better or let me know if I'm on the wrong track or wont work. Hopefully this helps
boobby
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Re: Improved Alternator for 860GT

Post by boobby »

i have the same set up on my 860gt, works really well. i put my rotor in in the lathe and shaved those fins off for a little more wiggle room
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Re: Improved Alternator for 860GT

Post by BevHevSteve »

I have a complete stator/rotor/regulator setup off a '98 ST2 available - this is the trick setup for all round case 750 motors...... Didn't know it would fit an 860 - I learn new things every day,...

https://store.bevelheaven.com/Electrica ... vel-Drive/

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Ducati/Euro Spares -> https://Store.BevelHeaven.com
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