gsx 750 e/et/ex 1981 Us Import to uk jetting issues

[Guest]

Hi everyone was wondering if I could get some advice,

got a us import gsx 750e 1981 in sunny (rainy) manchester uk,

trying to sort my jetting out as she's running lean drilled the pilot screw covers out as per a thread on here and adjusted them

Main difference I can see is the following between the two specs

usa needle jet y-4
uk needle jet y-5

Usa pilot air jet 150
Uk Pilot air jet 170


USA jet needle 5c28
UK Jet Needle 5c32 3rd

mains both same in the books at 112.5

local place advised going up one on the mains

would you guys alter the other ones to?

Massive thanks in advance,

Tom

This was with new plugs new oil and a ride round the block after buying it

[geol]

You rode around the block and determined the bike was running lean based on the plugs as shown in the picture? Put the plugs back in, leave the carbs as they are and ride the bike. Does it pull redline in any gear? Does it get decent fuel mileage? If so, the carbs are fine. The main jets alone are only the full contributor to the bike's operation with the slides fully open... in other words, why the heck would a shop tell you to increase the main jet size? The plugs would look exactly the same under the same riding conditions. Ride the bike for awhile and see if you have driveability issues or the pipes start to turn color or something tangible.

[steele01]

Done 140 miles on the bike picking it up (previous plugs were the same), that was a comment of a uk dyno tuner, from experience of setting these bikes up always 1 up on the main with the rest of the jets set to the uk setting

its hunting in the mid range, runs really hot and pulls ok, but pipes are already starting to blue all indicative of lean running,

Mainly curious about the differences between the other jets within the carb uk to us and the difference it will make

[bsharpish]

As a 30 year Suzuki guy and suzuki restorer/modifier and Brit in texas - yup they're always set lean here

Had similar issues with my GS1000 - went to UK jets and problems resolved instantly