Honda-SOHC

Couldn't agree more. I share a set of 4 clocks with another friend/motorists. Unless you have more bikes, cost of buying is hardly justified. That's why we shared and soon an owner of 2 350's will use them too. My experience is: once set you don't have to sync for a long time, very long indeed. As a matter of fact when you think they're out of sync, I would advise you to look for another cause. In my experience the carbs stay synced almost forever. Honda did a good job on this, after learning lessons with the 4-cable operated carbs on the early 750 models. Last time I used the set is some 15 years ago. On a few occasions I had the carbs on the kitchen tabel (for experiments with the needles) and decided to see how accurate I could sync by hand, using a small allen key for testsliding under the little cutaway section in the front side of the slides. I adjusted, testslided, adjusted, testslided etc. Then I drank a cup of coffee and checked it again, eyes closed for maximum touch. After mounting the carbs on the bike and attaching the set I was surprised I had managed to sync within 2 cm Hg(!), well within factory specs.
Maybe - just for fun - I will build a DIY as described elsewhere, because I like the idea so much (simple fysics). Gives me also the possibility to check if the 4 clocks are still within calibration after all the hefty movements. The homemade set can never lie. No negatives: you need no figures, just visual information that fluid is at the same level. For the rest of you: share. Less is more.

On my 500 I always managed two chains per one set of sprockets. No problem.

That 500/4 in the video sounds like a bag of old nails. A bit of set-up & carb balancing needed there I think.

If you mean the blue one, yes, that's what I thought... but maybe it's idling way below 1000 rpm.

Hi can anyone tell me, where the breather tube from the breather cover goes to? and where the two outlets on the bottom of the air filter box and the outlet on the air manifold?

To start with the latter, originally it had a tube as a drain. You could pinch it open for that.
The breathertube on later 550 models (and 500K3) were connected to the bottom of the air filter box. The idea was to recycle blow-by fumes through the foamfilter located under the paper filter element into the engine. I've seen quite some paper air filter elements that got fouled because of this. You can reconnect it but then you have to monitor things regularly. Or you could reroute the breather tube like on the older models (best seen on p 170 of the original Honda Workshop Manual CB500 - CB550) where it vents in the open.

Bastard. Carbs are the later PD type that were on K3.
 

Grey import maybe?