GT550 carb help

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2strokejohnny
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GT550 carb help

Post by 2strokejohnny »

need some carb help now been overhaulled with new Float valves replaced as they were shot and bike started first time after carbs were primed only thing is it is idling very high 4k and the idle screw is in as far as it goes, what next ? John
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canaletto5
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Re: GT550 carb help

Post by canaletto5 »

Was it idling ok before ? Double check you haven't got the push/pull cables around the wrong way. Kev
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Harrymail
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Re: GT550 carb help

Post by Harrymail »

When synchronising the slides, you must start with the idle adjuster a couple of turns out. This then allows enough adjustment of the tickover afterwards. As well as synchronising, the starting height of the slides needs to be set. If you have had the carbs synchronised, I suspect the start point is too high. They need to be synchronised again, with the slides set at the correct start height.

Paul
Currently without a GT, but looking
2003 Yamaha Fazer 600 Blue
2020 Triumph Street Twin Red
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2strokejohnny
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Re: GT550 carb help

Post by 2strokejohnny »

is there a guide somewhere i can download on how to re-sync the carbs ? John
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canaletto5
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Re: GT550 carb help

Post by canaletto5 »

John, for the bike to be running at 4k when it should be at idle would mean that the slide height would very noticeably higher than where it should be. Have a look at them from the airbox side and check the distance between the base of the intake and the base of the slide. If memory serves it should be about a maximum of 1/8th inch in old money. Synching is important but slide height needs checking

Have a scoot through this post, it has a link to the carb manual

viewtopic.php?f=14&t=12089&hilit=slide+height

Kev
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2strokejohnny
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Re: GT550 carb help

Post by 2strokejohnny »

thanks i've had a read up and although i don't do carbs normally i'll have a go,John
Suzuki GT750B
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2strokejohnny
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Re: GT550 carb help

Post by 2strokejohnny »

carb update
only had a little while to tinker the slides were high so lowered them all ticking over nicely so thought i'd have a go at balancing them which i done with the airbox off by running on 2 down to 1k revs then got it ticking over just above 1k, put the airbox back on........now not starting so will have to go through it all again tomorrow with the airbox on.
i did it with the airbox off as it's a bit easier with the shovel hands i got :mrgreen:
thanks for all the input,John
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Harrymail
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Re: GT550 carb help

Post by Harrymail »

My method is to sync them on the bench using a drill bit to measure the slide gap, then fine tune with an air flow meter when they are on the bike.

Paul
Currently without a GT, but looking
2003 Yamaha Fazer 600 Blue
2020 Triumph Street Twin Red
1968 BSA Bantam Sports Red
barney01
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Re: GT550 carb help

Post by barney01 »

Airflow meter makes it easier :D
https://youtu.be/9G5Hsenlv1g
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2strokejohnny
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Re: GT550 carb help

Post by 2strokejohnny »

well got the hairbox off again just to re-check the slide gap but can't seem to get it low enough for the correct 1/8 th or 3.2mm gap, lowest i can get is about 4mm any ideas ?
Suzuki GT750B
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