loom | Moto-Abruzzo

When it comes to electrics/electronics, we are all oh-so familiar with the fact that for the most part, things either work or don’t. But occasionally we get the mighty frustrating intermittent fault that dances between the two, then we also get the rare as hens teeth, slow failure. The one that takes an absolute age to travel from 100% working to finally broken, the kind of behaviour more befitting a mechanical part than electrical. Well that’s what I’ve just had!

Back in August of 2010 I fitted the Shindengen FH012 rectifier / regulator and I think it’s fair to say that it began its slow decline within a couple of years. The once steady 14.2V at 4,000rpm slowly ebbed away, a few millivolts here, a few millivolts there, year on year. By last autumn the charging circuit was giving me about 13.6V (idle) and 13.9V at motorway speeds.

After the incident with the stuck starter solenoid a couple of weeks ago, it seemed to shave off another 0.1-0.2V. On the return leg of our trip the Sparkbright battery monitor would dip from green (OK) to amber (not OK!) when the fan cut in …… such that I was turning the headlights off when we hit slow traffic in order to keep the thing charging.

Each year I’d checked the alternator, wiring, connectors and battery and everything tested just fine …… so was it the regulator? Time would tell I figured! In January I bagged a brand new Shindengen FH008 but hadn’t got around (galloping laziness!) to trying it out. So before the main Aprilia Caponord ETV1000 Rally-Raid Shindengen FH012 rectifier regulator power/ground cables were replaced it seemed only fit and proper to test the new regulator, then decide what to do about sorting the charging system.

The quickest test was to simply crimp some spades on the FH008 leads and plug them directly into the Furukawa sockets on the charging loom and see what happened – 14.4V (idle) and 14.5V at 4,000rpm is what happened! Most definitely the regulator rather than the alternator or wiring then.

The old loom was removed and inspected – all still in excellent condition. Even so, new cables, connectors and sheathing were ordered from the original suppliers and in went the FH008, back in the original location. With the bike buttoned up and a healthy voltage at the battery, it just left a moment for my eye to linger on the right hand side of the bike. Somehow it looks odd, naked, empty without the old rec/reg in front of the clutch, I’ll get used to it I know, but for now I do miss it!

Measured voltage at battery:

Idle (lights / fan OFF) – 14.4V and at 4K – 14.5V

Idle (lights ON + fog lights ON) – 14.3V and at 4K – 14.4V

Idle (lights / fan ON) – 13.9V and at 4K – 14.2V

Idle(lights / fan / fog lights + everything else* ON) – 12.8V and at 4K – 13.6V

* GPS / Intercom / K1 Camera / Heated Grips (high) / Cruise Control / brake lights

So what is this new-fangled modification to the starter circuit I alluded to in the last post? Well in a nutshell it’s a new loom (plug’n play) that goes between the starter solenoid and the main loom and also goes to the battery. Why?

As mentioned previously, the starter solenoid draws about 2.9A when energised and that power goes from the battery via 2x 30A fuses, through the ignition switch on the headstock, then up to the fuse box in the cockpit and back to the starter solenoid. From here it goes via the diode block down to the engine (neutral switch) or side-stand switch (and back up into the loom) and all the way back to the handlebars (clutch switch) before finally making its way back to the battery via the main earth (Ground) cable – phew!!!! That’s a lot of cable and switches, never mind the diodes. OK the fact is, this circuit has worked trouble-free for 14 years, why mess with it? Because my gut instinct is that restricted power to the solenoid over time makes for low-speed actuation and eventually, burnt contacts …. that’s my theory anyway!

I figured an easy way to make sure the solenoid gets lashings of fresh volts/amps is to make the circuit between battery and starter solenoid shorter and simpler – so in goes a small loom with another relay, a 20A unit exactly the same as used for the headlights. This relay is now activated by the starter circuit and its contacts switch fused-battery power direct to/from the starter solenoid – short and sweet!

This relay has a coil resistance of 70Ω and so only draws 170ma @ 12V so no problem with starter buttons or switches getting a little resistive over time as (for example) a mere 0.5Ω difference when set against the 70Ω coil is only 0.7% difference compared against the 4.4Ω of the starter solenoid coil where a 0.5Ω difference equates to over 11% difference. Bottom line – the whole circuit has an easier time!

The wiring is soldered direct to the relay spade connections and then slides into a 3D printed case and the case/contacts are encapsulated to keep the whole thing neat and tidy. Now the relay sits on top of the ECU held in place by a double-sided adhesive pad and the connectors tuck away neatly behind the battery.

If somewhere down the line it all turns belly-up, I only need to unplug the two connectors and reconnect the solenoid back to the main loom and it’s business as usual. So I figure I’ve got nothing to lose by giving it a whirl …… I’ll find out soon enough if it’s a thumbs-up or thumbs-down job!

Tag: loom

Replacing the regulator – FH012 to FH008

Running a relay race ……