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Running issue GT380

Posted: Sat Mar 21, 2020 8:10 pm
by Dbailey
So bike was running ok but not particularly well at higher revs. I took the plunge and bought a complete set of carb parts including needles, pilot and main jets, float vales and seats and lastly air screws and o rings. All of the parts are genuine original parts not pattern. The bike won’t idle very well and flat when you open the throttle but runs ok above 3 1/2 to 4K. If I completely close the air screws the bike will idle and pickup although not perfectly but way better. The only thing I changed in terms of baseline setup was moving the circlip to the middle position down one from previous on the needle valve. I did this to give more fuel at higher revs. I didn’t think needle valve position affected idle. I have had a check and can’t see any places where there are any air leaks...


Any thoughts guys? I’d like to get some opinions before I start ripping stuff apart again,

Thanks
Dave Bailey

Re: Running issue GT380

Posted: Sun Mar 22, 2020 7:20 am
by Alan H
Take the carbs off and send them to Baz.
He's an egg spurt.

Re: Running issue GT380

Posted: Sun Mar 22, 2020 8:35 am
by barney01
Idle problems are almost certainly caused by blocked pilot jet circuit or pilot jet bypass as these have a large effect on idle and up to 1/4 throttle opening. They are very difficult to access and it takes but a tiny foreign body to block it up.
If you have access to an ultrasonic cleaner thats ideal. New jets will not solve the problem if the passages are dirty or blocked.
If you have'nt fitted an in line filter do so, otherwise small particles of rust from the tank into the carbs.
Lastly just check that your choke pistons are returning as they should as if they stick open it will cause it to overfuel at idle and effect high revs too.

Re: Running issue GT380

Posted: Sun Mar 22, 2020 9:07 am
by Dbailey
Thanks guys...

Dave Bailey

Re: Running issue GT380

Posted: Sun Mar 22, 2020 9:14 am
by Dbailey
Sorry trying to look up Gaz (savs) to pm him for a strip and clean price...

Re: Running issue GT380

Posted: Sun Mar 22, 2020 9:16 am
by PaulD738
Dbailey wrote:Sorry trying to look up Gaz (savs) to pm him for a strip and clean price...
Hi Dave, it’s BAZ your looking for just search in the members list 8-)

Re: Running issue GT380

Posted: Sun Mar 22, 2020 9:49 am
by Dbailey
Thanks everyone...

Dave Bailey

Re: Running issue GT380

Posted: Tue Mar 24, 2020 5:31 pm
by 2strokejohnny
gt750 one,suppose this will fit other gt models ?

Re: Running issue GT380

Posted: Sun Mar 29, 2020 8:03 pm
by Dbailey
Thanks everyone ... update Barry is about to do his magic... thanks for the recommendation...

Dave Bailey