1983 kz750 fuel line size

i have one fuel line from my petcock to the carbs. I need to know what size(i.d.) it is, i dont want to guess, its either 1/4 inch or 5/16 inch. Anyone know for sure?

ended up going with 5/16

How did it end up fitting? good choice? I need to replace my line as well. thanks

I use 1/4". It's a snug fit, so I guess either size will work ok. The inside diameter of the petcock outlet tube is just shy of 1/4" so either size will flow enough fuel. Ed

On my 81 KZ650-CSR the fuel line is 5/16" & the vacuum line is 1/4".

On on the later models, they went to a larger fuel line. I think it's nominally 8mm. The closest to that is 5/16".

Some prefer a snug enough fit whereby a clamp isn't needed.

If the fuel line is difficult to fit onto the nipple, the end may be immersed for a few seconds in near boiling water, which softens it enough to slide easily over the nipple.

Good Fortune!

loudhvx wrote: On on the later models, they went to a larger fuel line. I think it's nominally 8mm. The closest to that is 5/16".

Yep. 1/4" is way too tight for the fuel line, increasing the risk of pulling out the nipple... don't ask how I know. hee. It's an easy fix.

martin_csr wrote:

loudhvx wrote: On on the later models, they went to a larger fuel line. I think it's nominally 8mm. The closest to that is 5/16".

Yep. 1/4" is way too tight for the fuel line, increasing the risk of pulling out the nipple... don't ask how I know. hee. It's an easy fix.

Interesting. On mine it's a snug fit, but not nearly tight enough to pull the nipple loose. Mine has the original 1977 non-vacuum petcock. Of course, it could be that the automotive fuel line I'm using is actually a tad over 1/4" even though it is marked 1/4" or maybe it's more pliable than some other types. Ed

martin_csr wrote:

loudhvx wrote: On on the later models, they went to a larger fuel line. I think it's nominally 8mm. The closest to that is 5/16".

Yep. 1/4" is way too tight for the fuel line, increasing the risk of pulling out the nipple... don't ask how I know. hee. It's an easy fix.

What did you do to fix it? I had one come out, but I was lucky and it pressed back in snugly.

What did you do to fix it?

I used Permatex Liquid Solder. I believe their Liquid Metal is basically the same product.
Apply a small amount on the outside of the nipple, then simply press it back into the petcock orifice. very easy.

YEs, 5/16".