Author Topic: CB500 Four - engine cuts off in idle  (Read 1978 times)

Offline Siloxious

  • Newbie
  • Posts: 28
  • CB500 Four - General Export K1
    • View Profile
Re: CB500 Four - engine cuts off in idle
« Reply #30 on: November 04, 2023, 02:29:28 PM »
@ Siloxious Just to satisfy my curiosity, when you set the timing of the ignition, did you first check the breakerpoints gaps?
As far as the carbs.
1.Verify fuellines have the right dimensions
The CB500/550s are very sensitive for a proper fuelflow route, so let us first establish whether everything is standard or not.The correct dimensions for the fuellines are: for the CB500 and earlier CB550s: 18 and 30 cm length for the models with the bowltype petcock and 17 and 28 cm for models that have the newer style petcock. Do not be tempted to have them longer. For the tube that supplies carbs 3+4, use the soft metal clamp in the middle front side as shown in the pic (btw, horizontal is good enough) for proper routing. Ideal inside ⌀ of the fuel lines is 5,5 mm. Outside ⌀ will be around 10mm. Have this and the lines will not kink. Abstain from extra inline filters. Some have been lucky with them, but my experience is they can't be trusted. Often it isn't that filter itself, but the rerouting of the fuel line that - sometimes intermittent - impedes a proper delivery of the gas.
2. To be sure, all four carbs receive the same amount of fuel, read this: http://forums.sohc4.net/index.php/topic,185754.msg2151647.html#msg2151647 When you do this test, realise it takes quite some time before the bowl is filled completely.

I’ve just checked the ignition timing statically and the bike idles good at 1100 rpm. As I have not a lot of time today, I’ll check the carbs tomorrow. Thanks for your advice!

Offline McCabe-Thiele (Ted)

  • Grogu
  • *
  • Posts: 6616
    • View Profile
Re: CB500 Four - engine cuts off in idle
« Reply #31 on: November 04, 2023, 03:55:08 PM »
I have heard of Das Motorrad from when I worked in Germany many decades ago.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline deltarider

  • SOHC Master
  • Posts: 1405
  • My kingdom for a turkey!
    • View Profile
Re: CB500 Four - engine cuts off in idle
« Reply #32 on: November 05, 2023, 12:54:11 PM »
I have heard of Das Motorrad from when I worked in Germany many decades ago.
Das Motorrad is big in Germany and German speaking countries like Austria and Switzerland. I don't know about now, but it used to be in Dutch kiosks as well. They carry out tests of products with typical German Gründlichkeit and - being so big - they can pay for laboratories when needed.

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal