Aftermarket upgrades that are actual upgrades.

A SH775 R/R on bikes with a 3 phase charging system is a no-brainer.  It's a series type R/R which means it helps protect your stator from return current over heat damage.  They are made by Shindengen and super robust.  Vastly superior to the stock R/R on OEM bikes from the KZ era.  You can pick up a used unit for between $35-$55 off ebay if you search carefully.  

I've done a few on my 77 kz650c that I think are major upgrades from stock, such as a o-ring or x-ring chain. K&s turn signal. LED headlight(which is now recommended by all insurance providers and motorcycle experts where I live). K&s handlebar switches after my old ones degraded. Oh and changing out all the old wiring from stock to new 16 gauge and using weatherpack connectors to create a wiring harness that can be easily disassembled if needing to remove it. After 40 some years the old wiring is very oxidized and corroded in some places. Which means higher resistance and then it means it is more prone to failure and also less efficient. So changing out stock wiring is a no brainer. 

I have been wondering what to do with my wiring. Can you get a new one or have to build it myself?

JL

I have heard you can buy a new one, but I didn't,  build mine, also because iI replaced my handlebar switches. But wiring an old bike like this is pretty easy. There is no ecu to wire.and everything pretty much has two wires, positive and negative. It took me awhile (but that's because my wife and I had a baby) but I got it done and it looks way better than the old original loom

Quality O-ring chain and sprockets geared towards the riding you do
More comfortable grips
Tires
LED lighting
Battery
brake pads
etc

Heated grips - I used  these  and they work great without drawing much power. They're also a bit thicker than stock grips, which I find more comfortable. However, they don't help much below 40 fahrenheit without a fairing or some other wind shielding. 

Every motorcycle I have bought since back in the early '70's to my latest one. The very first thing I did or do was replace the pogo sticks the Japanese call rear shock absorbers!!!! Back in the '70's S&W shocks or Koni shocks were the best you could get. Ever since the mid '80's Ohlins seem to work the best. Next to go were the O.E.M. tires. Hockey pucks had more traction than most O.E.M. tires over the years. A good pair of shocks or shock and a pair of sticky tires can easily transform any motorcycle into something that is fun to ride fast!!! Next thing is to install a steering damper. Those three things will turn most motorcycles into something that is a 100% improvement over what a stock motorcycle runs and feels like!!!!

Biggest joke on any motorcycle is the installation of any form of neon lights on any part of a motorcycle!!!!!!!

Pfff a lot, Koni's, APE needle mushroom for the clutch, smoothbores, Dyna coils/ignition, stainless steel exhaust, needle bearings  instead of ballbearings in front, heavy duty clutch springs.
   

These are weather pack connectors, year's ahead of the oem connectors. Fully water, dust and weather resistant. They come in 1 poll to up to 6 polls. Each wire has it's own seal as well. Very easy to assemble. This paired 6 poll unit cost me about $20. But they are worth it. And better than the stock non-weather resistant connectors. 

Back in the good old days, all we had to worry was the traffic/people ahead of us. Now with distracted driving, we have to watch behind us even more. So I always install Signal Dynamics Back Off Brake Module and it works with LED brake lights. A bit expensive, but well worth it to get driver’s attention.

JL

Did the same on my KZ to get more attention to the distracted/inattentive drivers behind me. Brake 2 Flash is an adjustable brake light flasher module and you can choose between 14individual flasher sequences.

 
 

 

This thread really blew up! Much more so than I expected, haha. 

Seems like a lot of recommendations for improved lighting and suspension. Obviously a lot beyond that, but those are recurring themes here. I think for me personally as a beginning rider, anything I can do to improve the handling will help inspire confidence. I may be looking into some front fork rebuilding with better insides soon. 

Good food for thought everyone, keep it coming!