Electrics advice

Hi All

I just recently acquired a 1980 900SSD - it runs well and is mechanically and cosmetically excellent - but the wiring/electrics looks a bit shabby and decidedly tired.
My plan is for a complete rewire and renewal of the tired old electrics and I’m seeking best advice on what components to use…
I’m viewing the wiring system as 3 sub-systems: charging, ignition and lighting etc. I’m looking for the best components for each sub-system:

Charging: New stator, rotor, regulator. - Electrex RO92 rotor, G92 - Generator, RR51 - Regulator Rectifier
Ignition: New digital system. Not sure which either Silent-Hectik http://www.silent-hektik.com/Duc_900SS.htm or elektronik-sachse ZDG3 http://www.elektronik-sachse.de/shopsystem/product_info.php?info=p23_digital-ignition-zdg3–ducati-beveldrive–bosch-.html
Lighting etc.: New central controller without traditional fuses. - MotoGadget M2 http://motogadget.com/de/elektrik/elektronische-steuerbox-m-unit/m-unit/m-unit-digit-tastersteuerung-u-sicherung.html

For the actual wiring, I’d like to bring the connectors up-to-date by using a weatherproof system such as as this: http://www.vehicle-wiring-products.eu/VWP-onlinestore/connectors/multiconnectors.php

Obviously, all the above amounts to a hefty bill - probably not far off £1k by the time the shouting is over.

Questions are
?Is it worth the trouble - or should I just ride the machine at risk of existing old components failing?
?Is it worth the expense - or should I just replace old dodgy looking wires and make do?
?Opinions on the components - are these be best or just OK and are there any other alternatives?
?Can I treat the electrics as three separate (if linked) sub-systems and replace each as a separate project?


Hello bolsover.
My 1984 Darmah is still running on the original alternator and the reg/rec only packed up a but 3 years ago after 70,0000 miles, I replaced it with and original Ducati Electronica unit, which is still OK.
I have replaced both sets of handlebar switchgear a few years ago as they are pretty much the same as late 70’s Suzuki GT250/380/550/750 and GS550/750’s etc, having said that they are now hard to get hold of due to the popularity of these Suzukis!
I have replaced the Bosch ignition pick-ups as the insulation on the originals was never meant to run in oil, and they disintegrated after about 25 years, I would definitely replace these unless they have already been done.
The Bosch ignition boxes however are still going strong and I as far as I know they are pretty good as there are plenty of spares available?
Everything else is still working OK, the red voltage sensor relay, flasher relay, even the fuse box.
I do like the look of the solid state protection block, that’s a nice idea.
I don’t have any info on either the alternator, the reg/rec, or the ignition system.
My connectors are also OK, but I do pack them with Vaseline to stop water rotting the copper connections, particularly the main one from the ignition switch.

Personally… I would:

  1. Change the ignition pick-ups
  2. Change the fuse box.
  3. Maybe the Reg/rec?
    And leave the rest?

If you need any more parts, try Andrew at http://www.mdinaitalia.co.uk/, if he doesn’t have it he’ll point you in the right direction.


Here’s another place for bike connectors, very good service when I brought some stuff last week!


Don’t fit a Electrex RR51 reg/rec I’ve had a few go bad as in overcharging and know of a few other owners who’ve had them go the same way.
I now fit the Shindengen unit from the early single phase 748/916’s, which I’ve found to be totally bullet proof.

I made my own extremely simplified loom for my ‘79 900SS wtih a Honda ignition switch, L/H handlebar Suzuki switch and run a Lucas RITA that runs off the cam bevel, with Dyna twin outlet coils for my twin plug heads.
It’ works a treat and has been totally reliable for several years now.

Steve R

Hi Kevin
Thanks for the advice. I’ve not actually looked at the pickups yet - but if the external leads are anything to go by, it’s likely the pickups need attention. I’ll get the cover off and take a look, if nothing less, it will give me the opportunity to replace the ropey old grommet. The fuse box looks like the original item; it has no cover though and I certainly wouldn’t fancy it’s chances if it got wet. I know replica fuses boxes (with covers) are available - but I like the look of the motogaget unit - no fuses - and some real neat features are standard.
I’ll continue with appraisal before making any decisions and easy sure to post progress here.
Thanks for link to kojaycat.


Thanks Mr R. I’ll be sure to look out the Shindengen unit.

Minor progress on this.

1 Fixed neutral indicator with a new switch.
2 Fixed side stand warning light - turned out to be a blown filament bulb - now replaced with an LED.

3 After a couple of short ride outs it became clear that there was a charging problem. The charge light would behave normally for the first few miles - but would then stick on until I turned the lights off/on. After a little searching on the Web and I found a post on the bevel heaven forum which hinted at over charging because of resistance in the battery>ignition switch >regulator sense circuit (and hence low voltage at the sense input to the regulator). More searching on the Web and I turned up an excellent little charge voltage indicator on eBay (200826330214). With the charge voltage indicator fitted, I quickly confirmed the suspicion of over charging - actually worse than I expected - at anything over 4k remember lights on or off, the unit indicated over charging. At this stage, I suppose the ‘right’ thing would be to fix the problem by sorting out the suspect wiring - but I decided to fit a new shindengen regulator instead - and just disconnected the original regulator. Charging problems look to be a thing of the past:-).

4 Turning my attention to the ignition pickup wiring now - to start with just replacing the crappy external spade connectors with couple of decent connectors and at the same time cutting back the wires to remove old brittle insulation (exposed conductors - eek) in an attempt to find something worth splicing new wire to.

I’m working slowly through the issues and checking to make sure everything still works after each modification. I think I will end up with a complete rewire - but I’d like to make sure the parts are up to scratch first!

Having had the dash apart to fix the side stand indicator bulb, I’m wondering if it’s worth replacing all the old indicators with LED - anyone done this?



I did the same with my 900GTS and 600SL Pantah. It was a bit fiddly on both but no real problem.



I gave up years ago chasing electrical problems on my owned from new 130,000+ mile '79 900SS, the OEM wiring was never that good in the 1st place IME.
So I finally bit the bullet and made my own superior/much simpler loom using modern components and heavier gauge wires, this was several years ago and it’s never given me any problems since.
Funnily enough today I’ve been repairing/upgrading the wiring on my '92 851/916cc bike (I’ve owned this for 16+year and 45,000 miles), I’d fitted a new genuine 996SPS loom to it 7 or 8 years ago and it’s already throwing up the odd problem. :unamused: Now there’s a surprise…NOT!!!
When I finally get around to finishing of my little '74 250 Desmo project bike (it’s 3/4 done so far), I’ll be making my own simplified/better quality loom for that one as well.

Steve R

I go with Steve R. The wiring can be simplified but the main components are pretty reliable being Bosch and ND. Main problem i have come across with old looms is poor connections and corroded connectors.
There is a very good firm up north that does Motorcycle wiring block connectors. this might help


As the riding season nears, at the weekend, I decided it was time to warm up the bevel. Now I know it’s been standing for a couple of months with the optimate periodically attached to give the battery a boost. It did start… eventually… but certainly not eagerly despite my efforts to prepare for the occasion by treating it to some new petrol. Once started and warmed up it settled down to a steady tickover - not real problems.

Now I ‘know’ it should have stared more easily so,I’ve finally bitten the bullet and ordered some hardware…

Silent-Hektik Power-Block ignition system + Motogadget M-Unit + M-Button.

Rewiring does not hold any terrors for me - but I’m not too sure about the Ignition set up. The Silent-Hektik on-line documents are rather confusing with the original German and English translations not being in agreement about the timing advance or advance curves to use! Also, it’s clear I’m going to need some special tools only some of which are available through the club.

I’ll probably need help.


Hello David.
Which type have you bought, is it the one that fits in the clutch casing a per the Bosch, or the one that sits behind the flywheel?
I’ve only seen one of these set-ups used, and it was Paul Klatkewicz he has just bought the one which sits behind the flywheel (I think) and at the time he was a bit puzzled about some of the setting too, I assume he got it sorted?


Its a Bosch replacement type intended to be fitted in the clutch cover. I’ll get a few pics of the kit posted in the next day or so. The kit looks to be well made and quite complete apart from a mating part for the pickup connector to the control box. The kit is a single pickup type and can only be fitted to machines with electric start as it requires 2-3 revolutions of the rotor before the control box can calculate the rotor position.

I’ve already emailed Silent-Hektik a couple of questions; the English instructions are not quite the same as the original German and don’t agree about the ignition advance curve to select and neither is the same as the Bosch data where static advance is concerned! Also, the the control unit has two selector switches inside whereas the documentation only mentions one. A prompt reply from S-H… It appears I have a new design unit with two switches, one to select the ignition advance curve and a second to select the rev limit.

As I understand the original Bosch unit should have 6 deg. BTDC static advance, 16 deg at 1800 RPM, 28 deg at 2800 and 32 deg at 4000.

The S-H unit it appears should be set for 8 deg static advance (for single spark plug) and, if the German document is to be believed, 36 deg at about 5000. If the English document is correct, they suggest 8 deg static advance and a curve that gives 42 deg at about 5000 RPM… eek!!

I suspect that some trial and error will be needed to select the correct curve.

Some Pictures

Main Unit[attachment=2]DSCN0046_001.JPG[/attachment]

Pickup and mounting plate [attachment=2]DSCN0046_001.JPG[/attachment]

Rotor and sundries [attachment=0]DSCN0049_004.JPG[/attachment]


Not sure what happened with that last post - all the picture captions got muddled!

All the piccys here:


Looks well put together, keep us fed with info David. :smiley:
The club does have a bosch pick-up tool for loan if you need it.

I’ve already suffered one failed warning lamp and replaced with a couple of LED’s and a voltage regulator. It works just fine but could be a little brighter.

As I will be doing a complete rewire and considering the warning lamps, converting all of these to LED types seems attractive - so, I ordered a few extra bits from Farnell to test. One Item is a E10 12V LED:


WOW - it’s bright when run off 12V battery. I need to check the space available in the standard warning lamp holders but provided it will fit (with space connectors soldered in place) and will stand up to the higher voltage from the generator, these look like a good option. Just one component and a bit of soldering.

They’re a swine to get apart, they are glued at the base.
I scored the joint with a knife