Reddit reviews Yamalube Carburetor Cleaner Dip 32 oz.

Most 75 and 76 US spec 400Fs (400F0 and 400F1) have the flat handlebars as well. My 75 has them. Didn't think the US spec got the high handlebars and forward pegs till 77 (CB400F2).

I agree the starter switch is likely the cause of the headlight problems. The current for the headlight actually flows over that switch. Here's a link to a relay kit that will fix that.

Also the yahoo CB400f group has a set of pictures that show you how to repair the switch if its salvageable. You can also find NOS switches on ebay if you look hard enough.

Good Luck on sorting out the issues and getting it back on the road. I have a good deal of work to put into mine as well.

Some more useful CB400F links:

Electronic Ignition kit.

Honda Sohc4 forums

Honda Service Manuals and Parts Lists

3000 mile maintenance:

• Clean all carb passages -- Try this for badly gunked up carbs: Yamalube Carb cleaner
  
  May need to rebuild carbs if jets are badly varnished.
  
  
• Change oil & filter
  
• Change air filter
  
• Change spark plugs
  
• Adjust cam chain
  
• Check and adjust valve clearances -- need .002in feeler gauge
  
• Check and adjust points and timing (or replace with electronic ignition)
  
• Vacuum sync carbs --
  Carb sync tool
  
  
  
  11mm master cylinder thread on sohc4.net.