Testing digital indicator

[grubbytech]

There's probably a post somewhere about this BUT I haven't found it. Does anyone know how to test the digital gear indicator?
I've got an issue with my GT750L in that the gear indicator doesn't work at all. I've fitted a new switch so I know that's OK but I found a broken wire in the loom from the switch to the headlight shell. It's the white/yellow wire, could this cause the indicator not to work at all? Anyway I've got a mate who's going to replace the broken wire in the loom & replace the heat shrink around the loom, but I'd like to test the indicator unit itself just in case it's knackered too. It'd be just my luck that it is as it seems that the more I look the more I find wrong with this bike!

[CJB]

I think the gearbox switch and its associated loom just provide an earth return for each LED segment. So if you've got power at the indicator end (orange wire) and continuity through the loom to the switch on each of the six cables then the likelihood is the LED unit has passed away. One broken wire would equate to one "number" not working. the LED unit also contains some electronic components to control/reduce the voltage etc. Others will correct me if I am wrong in this assumption.

Ian (oldjapanesebikes) referenced a US thread looking at adapting a modern display unit from Ebay a while ago.

http://www.suzuki2strokes.com/forum/vie ... =indicator

[grubbytech]

I downloaded the wiring diagram in the end & worked it out for myself. Well as an aircraft engineer it'd be a pretty poor show if I could suss out 1970's Japanese motorcycle electrics wouldn't it!
As you say the orange wires on the bike are a live bus loom & the rest of the cables are earthing points. As it turns out I have some segments that aren't working so I too bout myself a cheap red LED indicator from Ebay (Eblob!) http://www.ebay.co.uk/itm/Red-Universal ... 0920824431
so basically I repaired/replaced every bit of the indicator system!

[CJB]

Sounds like you've got a bike like mine, every time I take something off I find something else wrong or bodged! but its going back together now, final £200 worth of parts arriving today!!

[yeadon_m]

I once bought a bike described as a nut and bolt rebuild. It wasn't what I expected. OK, every nut and bolt had been f***** with, but most of the nuts didn't properly fit the bolts, many of the latter had head sizes recognised by no standard spanner I'd ever seen. It was no better under the pretty covers. I hated it and moved it on after a year!
No sticking power, me :-))
Mike

[grubbytech]

To be honest I'm seriously thinking of stripping all the looms down & building them from scratch to be sure they all work safely.

[CJB]

All the looms are available NOS the problem is the 1970's main power BUS is hopeless, I've fitted an electronic regulator/rectifier however the reference voltage on the standard (new) loom is 1.5 volts less than the battery voltage, needs a relay to power from the battery.

[grubbytech]

Maybe using new cables rather than the ones that are 30 odd years old would make a difference.

[yeadon_m]

Grubby tech,
There is a loom expert on this forum:
http://www.kettleclinick.com/viewtopic.php?f=14&t=2674
He can tell you all the design weaknesses. As said earlier, the unswitched live cables are too small, and others too.
Cheers, Mike

[CJB]

Maybe using new cables rather than the ones that are 30 odd years old would make a difference.

Front and rear harnesses on mine are brand new, the cables are to small on the main power BUS (orange) not a problem unless you upgrade some of the 70's tech to millennium electronics that need accurate voltages.

Easier than my BM though that has a CANBUS system which makes adding any accessories a nightmare, either run from the battery or for BM official accessories it has to be plugged in to the BMW mother ship to instruct them to work!!