Honda 5.5 and 3.5 mm fuel line replacement?

i am doing a carb rebuild on my 2000 BF75A and thinking of changing out
all the fuel pump and carb fuel lines
And I wondering if the gray fuel lines with red stripe. are original ones
and is it recommended to buy the Honda oem lines
or ok to use automotive fuel line which are not 5.5mm and 3.5mm
I think 1/4” works for one of them

Hi,
I'm not sure about your "red stripe" question although I think you're probably right about it being factory original.

5.5mm is equivalent to 0.216 in. so 1/4" (0.250") would be too large. It would be better to substitute 7/32” line as that is equivalent to 0.218"
and is very close.

I just purchased a fair amount of 7/32" vacuum line at O'Reilly's but not sure if that's what you need/want.

3.5mm is equivalent to 0.137 in. so the closest fractional line would be 1/8" (0.125"). That would be a "stretch" fit and might put the line under enough stress that it could fail prematurely. Not a comforting thought when dealing with gasoline but it would work in a pinch.

I may be wrong but I believe that most auto parts stores now carry lines of both metric and fractional sizes and I'm fairly certain that you can buy metric fuel and vacuum line on the www. these days.
Most Japanese brand motorcycle dealers can probably fix you up with some too..So, there should really be no need to compromise unless you're out in the wilderness or something.

Good luck with your project.