Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: Peterplank on March 18, 2026, 09:50:08 PM

Title: 500 fuel pipe too long ?
Post by: Peterplank on March 18, 2026, 09:50:08 PM

Carbs fully rebuilt inc new fuel pipes, pleased to say bike started and running nicely.. I did 10 miles and it started to feel lumpy like running out of fuel and just about running..
When I got home and had a look around I noticed one of the fuel pipes looking a bit flat on the bend under fuel tap.
Could it be that pipe ok and staying round when cold but when everything heated up pipe can flatten and starve of fuel if an it's inch or so too long ?
Cut a bit off and started fine but can't try it till tomorrow...
does anyone have experience of this ?
Obvs hope so as a simple fix
:o)

Title: Re: 500 fuel pipe too long ?
Post by: Bryanj on March 18, 2026, 09:58:57 PM

What fuel pipe are you using?

Title: Re: 500 fuel pipe too long ?
Post by: McCabe-Thiele (Ted) on March 18, 2026, 10:00:10 PM

I think the pipes should be 180 mm & 300 mm long .

Title: Re: 500 fuel pipe too long ?
Post by: Peterplank on March 18, 2026, 10:13:34 PM

Using smooth nitrile fuel pipe, not reinforced..
I did cut to 300 and 180 but was too long.

Title: Re: 500 fuel pipe too long ?
Post by: Johnny4428 on March 19, 2026, 06:45:25 AM

I had a similar problem with my 750, ended up putting a spring over the pipe to smooth the bend out and stop it kinking. Always thought the design of these taps in relation to their position was wrong. Horizontal outlets would work much better.

Title: Re: 500 fuel pipe too long ?
Post by: McCabe-Thiele (Ted) on March 19, 2026, 08:09:20 AM

Quote from: Peterplank link=topic=32553.msg316634#msg316634 datree=1773872014

Using smooth nitrile fuel pipe, not reinforced..
I did cut to 300 and 180 but was too long.

My pipe is reinforced, I used the Gates pipe as that was the brand fitted by Gerben or PO.
I tried a smooth Nitrile pipe, it seemed to go very soft quickly, as I had to take the Carbs off again I replaced the pipe.

When fitting the Gates Pipe lengths changed as I fitted dual in line alloy filters, they are virtually hidden by routing under the carbs.