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Discussion Starter #1
Has anyone ever physically chopped a F4 750 fuel line ( tank to fuel rail ) and got an accurate on the inside bore dimension.

I have a post 750 fuel line back home so I can chop that myself to measure unless anyone has that data also.

Would be useful to know.

cheers

joe
 

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Joe;
didn't the early 750s use clamps on the hose instead of John Guest fittings?

if so its probably 5/16" like the fuel rail :popcorn:
 

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Discussion Starter #4 (Edited)
Thanks guys. Yes the 750s had an unlined rubber fuel line ( 5/16 thanks ) which is clamped to the fuel rail and no John Guest fittings. These original lines are old now and should be changed for new 5/16 injection hose . 3/8 barb metal quick connect fittings and not 1/4 here for a tight fit..clamped.

The 1000cc bikes onwards have a rubber fuel line ( 5/16 ? ) with a hard plastic inner liner. There are John Guest fittings at the fuel rail.
The plastic liner grips the barbs both of the John Guest fitting and the quick connects very tightly negating the use of clamps.
Its important to understand when upgrading plastic quick connects for metal ones that the length of hose which had been gripping the plastic barb must be cut off flush.
It is a mistake to break out the plastic inner thinking that the rubber outer can grip the barb satisfactorily.It will swell and fail.
The plastic inner ( a fresh sector now), must be slid over the barb as this liner is the performance part of the hose.
It is also a mistake to force in a 3/8 metal barb as this will damage the hard liner. This is probably where the temptation arises to hack out the plastic inner and benefit from the larger bore of just the rubber. Dont do this .Use a 1/4 barb quick connect inserted in the plastic liner.

A good solution if your old hose is in bad shape is to obtain new 5/16 injection hose, 4 clamps, 2 - 3/8 barb metal quick connects. The old John Guest fittings should be carefully removed from the old hose and re used.
There doesnt seem to be a source for these... ( more research required ).

When changing lines 3/8 fuel hose hasnt been popular as it is cumbersome and doesnt match up with the John Guest fitting properly.
Joe

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