SOHC.co.uk Forums > CB500/550
CB550 Tuning Advice
taysidedragon:
Buy OEM fuel pipe from a Honda dealer. Might cost a little bit more but is safe to use.
Oddjob:
I have 10 metres of OEM fuel line I imported from Japan before I got ill. Cost me an arm and a leg, averages out at £10 a metre if you want any.
Neilw:
--- Quote from: Oddjob on October 13, 2026, 01:47:35 AM ---I have 10 metres of OEM fuel line I imported from Japan before I got ill. Cost me an arm and a leg, averages out at £10 a metre if you want any.
--- End quote ---
Thank you, i ended up ordering from Honda Classics - https://www.honda-classics.co.uk/shop/Fuel-Line-Tube-Pipe-5-5x10mm-x-1M-length-MIS385-p742073066
K2-K6:
--- Quote from: Neilw on October 12, 2026, 05:52:18 PM ---
--- Quote from: K2-K6 on October 12, 2026, 05:14:53 PM ---The suggested action is correct.
Essentially the engine idles almost exclusively on the fuel metered through those idle jets, the main, plus needle fuel route virtually closed with throttle closed.
Using choke, causes the vacuum in intake tract to rise, leading to fuel being pulled through both main jet and whatever it can get via idle jets .... that fuel will not be pulled through those routes (if partly blocked ) without the increase in vacuum the choke gives. Hence the stall when choke is fully opened.
Sound logical?
Your description, experience and the gpt effectively agree on cause.
--- End quote ---
Thank you, i'm floundering around in the dark tbh, so your opinion and explanation is very helpful. I'm getting a master at whipping the carbs off/on, having done it so often, so that's my job tomorrow.
--- End quote ---
As you're finding here, substantial part of good running is dealing with problems that simply prevent the components working as they should. Not optimisation as such, but a little frustrating in chasing things down completely to enable the normal functioning in the chain of parts that interact.
A good description of fault, as you've provided in observation here, will allow us to point at probable cause to help in untangling those symptoms.
It may be helpful, to run without the airbox in making it easier to pull carbs on and off at least while getting a baseline established that will see all idle circuit clear and functioning. This won't allow or facilitate good analysis in riding it, but just speed up the frustrating part (most have to go through this ) of getting fuel system fully clean and flowing as it needs to be. At that point, a full fit and test with everything in place should give a much better picture.
Neilw:
--- Quote from: K2-K6 on October 12, 2026, 05:14:53 PM ---It may be helpful, to run without the airbox in making it easier to pull carbs on and off at least while getting a baseline established that will see all idle circuit clear and functioning. This won't allow or facilitate good analysis in riding it, but just speed up the frustrating part (most have to go through this ) of getting fuel system fully clean and flowing as it needs to be. At that point, a full fit and test with everything in place should give a much better picture.
--- End quote ---
I was wondering about the airbox; it is probably the biggest faff bit of the process, so thanks for the tip.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version