Just finished a clutch spline lube job. Never been done spline okay 125000 km. I noticed the ground cable that goes to the housing near the gearshifter seemed very light. Any advantage to increasing the wire size?
Cheers

Depends what you mean by 'light'. What's the diameter? Is it the OEM cable? To help matters, you can unscrew the cable from the gearbox and clean up the corrosion that's bound to be there.

When you loosen the bolt holding the cable to the transmission case one might here a "crack" sound, a definite sound of corrosion and need of some attention.

Now that we are somewhat on the topic of ground/earth cables, I just produced this video today for my YouTube repair/improv comedy channel.

Some of past post suggest a second ground to the starter bolts. Also said early ks had light gauge ground wire. Mine is 87 built June 86 so I assume it is the light wire. No electrical issue yet but may replace with heavier gauge, can't hurt.
Like the 6mm wrench in the footpeg, will do.

I think the ground cable always seems a bit thin because the insulation on it isn't all that thick. The cable itself is 6.0mm sq. (per the handbook that came with early Ks) The cable on K's is good quality, much better than the stuff on later BMs. That said, only good can come of upgrading 30/40 year old wiring, even if it only results cleaning and remaking the connections.

I replaced the ground cable on my bike with a heavier gauge one because I felt the OEM cable was too light a gauge.  The sum of all the current consumed by the electrical devices on the bike travel through that wire on the way back to the battery.  A larger diameter wire means less resistance, although we are talking milli-ohms difference, and less voltage drop with. greater available voltage to the bike's electrical devices.  There could be a significant return current, in the tens of amps..

robmack wrote:I replaced the ground cable on my bike with a heavier gauge one because I felt the OEM cable was too light a gauge.  The sum of all the current consumed by the electrical devices on the bike travel through that wire on the way back to the battery.  A larger diameter wire means less resistance, although we are talking milli-ohms difference, and less voltage drop with. greater available voltage to the bike's electrical devices.  There could be a significant return current, in the tens of amps..

Yes agree rob
The start relay is rated at 80 odd amps....given this and knowing there is likely another 8 amps in ignition and other demands ...6 mm seems a bit short of the number reguired to keep available current without too much voltage drop...in awkward situations
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I replaced the ground wire on several of my bricks.  The reason was to add an emergency disconnect.

When replacing that wire, go to a place that sells wire for marine applications, a boat supply or chandlery.  Get marine grade wire, the good stuff will have thinner conductors and better, thinner insulation that will make the wire a lot more flexible, and make sure the conductors are tinned copper to prevent corrosion.  It's more expensive, but you are only getting a couple feet.

the ex service model i have here has the ground wire doubled and a larger flat strap type ground from the frame to the bottom yoke ? not seen that one before 

On my various K bikes I've generally cleaned up the connections then made up a heavier gauge wire, and added a minor second one to a solid earth point on the engine, or the starter body hold-down screws.

Then, of course, there's me. When I make a complete new loom I earth everything back to the battery through the loom and don't pick up the frame. I make a nice new battery cable too. Result? If the battery earth is screwed nothing goes through the main loom - no start but no meltdown either.

Awkward git. Of course I am