complete rewire, but what would you have done differently?

[MikeD]

I'm going to be completely rewiring the GT750 front to back, I untaped the rest of the original harness last night, what a disaster - the middle of the harness had been completely cut at one point, all 8-ish wires and then spliced back together. Lots of cracked, burnt wires, wires buried in the electrical tape wrap that went no where, etc.




I already know I'm upgrading to a shindengen FHXXX regulator, just trying to figure out if a shunted or open style will be easier on the stator long term and how much output I'm needing. I'll also be adding a relay for the headlight to run directly from the battery. But other than that the harness should be pretty standard, but open to ideas if I've missed something.

Heading out to the garage with the blown up copy of the wiring schematic to measure wire sizes and lengths, and see which circuits use which size wiring to get a starting point.

So for those that have rewired sections or performed a complete rewiring - what would you have done differently in hindsight? different/upgraded/weatherproof connectors? changing wire gauge for certain circuits? added relays? intelligent fuse blocks? LED turn and brake lighting? Something else?

[jabcb]

The Shindengen FHXXX regulator is for an alternator with a permanent magnet rotor, & is not compatible with the GT750’s alternator.
http://www.shindengen.co.jp/product_e/e ... talog.html

Your GT750 has a field coil. The voltage regulator controls voltage by controlling how much current goes to the field coil.

[MikeD]

Took a harder look at the parts manual, clearly this stator is much different where the rotor spins in the middle vs outside. I haven't had the side cover off yet so didn't know that style existed under there.

so this is a electromagnetic rotor in this alternator, but it uses brushes... is there any upgrade/swap for a permanant magnet rotor? brushes are just another point of possible failure and a pitb, but the real question I'm trying to search around and answer is how do I upgrade into a modern series MOSFET R/R?

[jabcb]

Suzuki GS-series bike alternators have permanent magnet rotors. They are well known for having problems so replacements are readily available.
The GT750 alternator is similar to what cars used at the time — they aren’t as problematic so there aren’t good replacements.

For a big benefit in the pitb department, I’d replace the points ignition.
Brushes hardly ever need replaced. But it is a good idea to have some in your spare parts inventory in case they become NLA.

If you are going to keep the stock electrical panel under the left side cover, then Oregon Motorcycle Parts has good replacements for the stock rectifier & voltage regulator. They are modern components that mount on the electrical panel just as the original parts do.
http://www.oregonmotorcycleparts.com/Products.html

[MikeD]

Just emailing Uwe about the ELZ3Coil elect ignition that I ordered about 6 weeks ago to see where it is at.

> If you are going to keep the stock electrical panel under the left side cover

y, electronics are going to live under there still (starter relay, etc)

Oregon doesn't discuss much of the features of their R/R's....

[jabcb]

I agree that R/R design is important for high-output alternators that have permanent magnet rotors.
There are two basic designs:
1) run the alternator at maximum output & control voltage by turning excess output into heat (all that heat is hard on components)
2) allow alternator voltage to vary & control bike voltage by using only as much current as the bike needs (those nifty Shindengen R/R that the GS-bike guys like)

The GT750 voltage regulator controls the alternator output, & the bikes voltage, by regulating the amount of current that is sent to the field coil (the rotor).
The alternator only outputs as much current as the bike needs.
The voltage regulator doesn’t create much heat so the part doesn’t have lots of cooling fins.

Rectifiers are pretty simple devices. Modern rectifiers are more efficient and produce less heat than the stuff they used when our vintage bikes were new.
That’s because diodes now use silicon rather than selenium.

For these reasons I don’t think the design details of the Oregon parts are much of an issue.
Same thing as when you go to the auto parts store for a car alternator (which has a built-in R/R) because that R/R design isn’t that much of an issue.

But if it helps, maybe you should ask the guys at Oregon Motorcycle Parts.

[akendall1966]

Re your OP.
Did a complete rewire of my T500, only regret so far is not diligently recording the colours of the wires used in a diagram, but its not a complicated set up to trace through when needed.

Here's what i did:

All new wire, modern stuff is thinner for the same current rating and fresh insulation is flexible and isn't going to crack readily.
Used regular Japanese style bullet connectors everywhere except alternator connection to main loom and ignition pickups / neutral switch where I used multi-poles Molex and 1/4" blades for the alternator (current capacity)
Used three relays to do the heavy lifting and take the strain off 40+ year old switches, main power relay activated from the key switch, lights on/off also switched by the key and a change over relay for dip / main switched by the handle bar switch.
Electronic flasher unit so I can use either LED or incandescent lamps, had a separate output for the idiot light as a bonus
4 way blade fuse holder so I can get fuses anywhere should I need it, different circuits fused appropriate to the expected load.
Modern single phases reg/rec with all the coils on using the existing alternator
Ignitech TCI ignition + new colis and fabricated some plates to fit the pick-up where the point used to be.
Mostly wrapped the loom in fabric tape rather than PVC sleeve easier to recover your screw ups More visible sections are sleeved to look period.
Not finished yet but will convert headlamp to a BA20D style fitting away from the hard to find OEM bulb.

I wanted reliability and to be able to pick up consumable parts easily should a loose a bulb while out.

[tz375]

Mike, that is a bit of a mess for sure. It might be cleaner to just get a replacement harness. You would still need to strip the connectors and clean the terminals and inspect it, but that would be a simple approach.

On a custom bike, I typically install modern waterproof latched connectors from Eastern beaver and I put relays on the ignition and headlamp. There was an Oregon regulator on tone of my bikes, so I'll just fit it. I have been lucky with OEM gear, but I prefer to use an RA77 combine regulator/rectifier if I am wiring from scratch.

[dag]

Not sure if this helps, but I use a 8 ton wire crimper to get clean super strong conections, can't stand for a connector to fall off a wire:

Link: http://amzn.com/B00KS5DY14" onclick="window.open(this.href);return false;

I've have had very good luck with marine wire for it's anti corrosion properties.

Link: http://amzn.com/B000NV0G0U" onclick="window.open(this.href);return false;

If soldering is needed, then stay brite silver is the strongest:

Link: http://amzn.com/B0015H6JYS" onclick="window.open(this.href);return false;