Carb Tuning GT550L

Getting your blazingly fast Suzuki powerplant to perform even better!

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Hush
Around the block
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Joined: Mon Jun 29, 2020 11:31 pm
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Suzuki 2-Strokes: 74 GT550 L 73 GT250K

Carb Tuning GT550L

Post by Hush »

I can't get my tachometer to settle so I am thinking the carb tuning is out, this is a new done nil miles engine, starts first kick, runs happily but bouncing tach tells me something is not right with the air mix. I have tried the old remove 2 plugs and tune the last cylinder but bike won't run on one so that was a fail.
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jabcb
Moto GP
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
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Re: Carb Tuning GT550L

Post by jabcb »

How is the tach bouncing around?
Tach problems & tach cable problems can cause the tach to misbehave.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 project & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Cliff56
On the street
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Suzuki 2-Strokes: Original owner GT550L

Re: Carb Tuning GT550L

Post by Cliff56 »

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GTandcbr
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Suzuki 2-Strokes: suzuki gt 550j
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Re: Carb Tuning GT550L

Post by GTandcbr »

Best way to tune the carbs by far is with an airflow meter. Then you know all three are sync'd together.
https://youtu.be/9G5Hsenlv1g
98 carb Blackbird and GT550j
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jabcb
Moto GP
Posts: 3708
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: Carb Tuning GT550L

Post by jabcb »

Interesting. Don't think I've ever seen one of those meters. Learn something new every day.

Link for the air flow meter? Any particular brand recommended?
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 project & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
GTandcbr
Yeah Man, the Interstate
Posts: 589
Joined: Tue Mar 10, 2015 12:35 pm
Country: WALES
Suzuki 2-Strokes: suzuki gt 550j
Location: Wales

Re: Carb Tuning GT550L

Post by GTandcbr »

This really does smooth the engine running
https://www.ebay.co.uk/itm/Synchrometer ... 890.l49292
So the proceedure i use is as normal warm the engine first and then remove the airbox.
Get the bike started at tickover then using the meter pushed in the throat of the carb set all 3 carbs to read the same using the cable adjusters on the cap.
Then using the cable adjuster under the twistgrip get engine to rev at 3000 and repeat balancing the carbs.
Then go back to idle and set tickover using throttle valve screws.
This i do every time carbs or airbox is off.
The meter measures how much air each cylinder is sucking and so all three are pulling the same. :o
98 carb Blackbird and GT550j
Cliff56
On the street
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Suzuki 2-Strokes: Original owner GT550L

Re: Carb Tuning GT550L

Post by Cliff56 »

I use a manometer on mine and set all three carbs at once.
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