Honda-SOHC

Hi all,

I’m looking for some advice on tyre sizing for my CB750 K4. I’ve been doing some research (with a bit of help from ChatGPT), but I’d really like some human input from riders who’ve tried different setups.

My bike currently has:
Front: 4.10-19 (≈ 100/90-19)
Rear: 5.10-18 (≈ 130/90-18)

I’m planning to fit a set of Avon Roadrider MKII tyres, and I’m debating whether to stick close to stock or keep the slightly upsized look it already has. Here are the options I’m considering:

Option (A):
Front: 100/90-19
Rear: 120/90-18 (closer to stock)

Option (B):
Front: 100/90-19
Rear: 130/80-18 (chunkier look, slightly lower profile)

Option (C):
Something else entirely — if you’ve run different sizes that you feel work better, I’d love to hear.

Hi all,

I'm in the process of stripping the carbs on my K4. Does anyone have experience with the David Silver pattern parts carb set? Are they any good? Or should I consider spending the extra £60 difference for the genuine sets.

Thank you

Hello everyone, I'm new here 

I've recently purchased my first CB750 K4, a US import from a dealer. I've done some basic restos in the past, mainly on smaller engines (DT50, CB125, YZ125) but I would consider myself a newbie wanting to learn really.

Anyway, the bike was running at the dealership after being hot-wired and setup on a dummy fuel line. Having got it home I started to investigate the wiring a little further and found that the fuse box and the safety unit were missing, the live battery cable was also corroded (see pics). Replacement parts are on their way.

My only concern is, it looks as though there has been some heat in the wiring at some point - the harness tape looks like it's melted in some places. I can't see any bare copper wires showing, the wire insulation looks ok. That being said I'm still a little concerned about hooking up a battery to it - fire extinguisher at the ready!

A couple of hypnosis I've pondered (this is where I would appreciate your expert input)...

1. Maybe someone at some point, has hooked the battery up the wrong way round, hence the melted tape and the looks of the starter ground wire.
2. There has been some external heat in this area (unrelated to the wiring), hence there isn't any bare copper wire showing (seems unlikely to me though).
3. There is a dodgy ground somewhere in the harness. There is evidence that someone might have been playing about with the indicator electrics and headlight.   

Any thoughts or observations are appreciated