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Electrical components for 900ss

Posted: Wed Aug 11, 2021 9:17 pm
by Blackandgold
Hi, I'm currently putting together a shopping list for my electrical parts but have a few questions.

900ss 1981. KIckstart only. I'm planning on learning and doing as much as I can, then getting a professional to check over everything. I have the old loom with components but have purchased a new loom and am replacing components as necessary. So far I have, new coils and ignition boxes.

1. I cant see any resistors here, do I need to get some? They seem hard to find...
2. Do I need to replace the regulator? I'm assuming yes but thought I'd ask.
3. I've added some images for what I have... some parts I've not identified yet so any help is much appreciated.
4. Any advice on sourcing a fuse box

Thanks! - J

Re: Electrical components for 900ss

Posted: Fri Aug 13, 2021 9:39 pm
by 81mhr900ss
You are asking a little late as you have already bought some expensive parts! I would have strongly advised you to go with a more modern electronic ignition. This would mean no Bosch boxes or resistors. Check out this thread showing lots of pics of my mods: viewtopic.php?f=19&t=5415

I do recommend getting a Shendingen regulator but I did this to protect my new electronic ignition. If you have your heart set on keeping things as OEM as possible, I have a pair of resistors from my 81 MHR that are not in use. There are so many Ducati owners in Oz that you should be able to source these locally (I'm in Canada). Bevel Heaven sells fuse boxes but I decided to replace my Ducati one with a modern blade fuse holder, super cheap from Amazon.

The parts in the pictures you shared:
- brake light switch as labelled - should be two, one at front on the hydraulic splitter and one at the back on the rear caliper.
- no idea what this thing is.
- old, non oem regulator.
- ignition boxes as labelled.
- relays - no idea what for. The bracket looks homemade. My 81 MHR does not have these and I'm pretty sure our original electrics are the same.
- flasher relay
- new coil block as labelled. The resistors should be attached to this block.

Do you have a wiring diagram?

I'm happy to help any way I can. Post lots of pics!

Rick

Re: Electrical components for 900ss

Posted: Fri Aug 13, 2021 9:51 pm
by 81mhr900ss
I took a look at the wiring diagrams for 81 SS bikes (there are at least 3 depending on market) and none show any relays. Ducati electrics are not well designed; the lack of relays means full load goes through the switches and sometimes the switches can get damaged so it is not uncommon to see aftermarket relays used to bypass switch loads for headlamps. Another common problem is to see the yellow wires from the alternator hard and crispy at the regulator terminal ends; the load is too much and the wires overheat. I replaced a short section of mine.

Re: Electrical components for 900ss

Posted: Sun Aug 15, 2021 3:44 pm
by Blackandgold
Hey Rick, thanks so much for taking the time to help out!

To be honest I would have preferred to go with a more modern solution... Munit or something similar. Your bike has a nice clean setup there.

The new electrical parts are ones my dad installed so he must have been set on keeping it close to original. I've just purchased a new regulator and brake switch, battery setup etc. Trying to respect the way he was building it :)

Thanks for the great advise and the offer of resistors. If I have any trouble sourcing them locally I'll get in touch. cheers!

Re: Electrical components for 900ss

Posted: Mon Aug 16, 2021 12:01 pm
by BevHevSteve