Carb Overflow GT550

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Tino996
Posts: 19
Joined: Wed Jan 10, 2018 6:41 pm
Location: gatwick

Carb Overflow GT550

Post by Tino996 »

Hi gents, my name is Martyn, I've not posted on here for ages, but I need some help and advice if possible please.
I'm now restoring a GT550 1974L, its going well, but problems with the carbs overflowing.
I have replaced all the needle and seats, all floats, throttle valve needle and jets. fully cleaned all carbs.
I have set the float level as per Suzuki shop manual. Upon fitting, everything seems fine, engine runs well, picks up and idles ok. I leave the bike for a couple of days, and notice quite a lot of fuel coming from the overflow pipes. I have swapped floats around and adjusted many times, but still the same result after a couple of days.
I'm no expert, and I don't know what to try next?
can anyone suggest further checks or advice please?
Thanks
Martyn
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canaletto5
Posts: 5228
Joined: Tue Jul 23, 2013 8:43 pm
Location: Derbyshire

Re: Carb Overflow GT550

Post by canaletto5 »

Hi

It's possible that your fuel tap diaphragm is allowing fuel to the carbs whilst is in in the Run or Reserve position. I assume you don't leave it on Prime?
Tino996
Posts: 19
Joined: Wed Jan 10, 2018 6:41 pm
Location: gatwick

Re: Carb Overflow GT550

Post by Tino996 »

Hi, thanks for your thoughts. I have been wondering if the fuel tap was at fault. Fuel does seem to flow to the carbs when it’s either placed to on or reserve! When on reserve, should there be any fuel getting through when engine not running? Perhaps the vacuum is leaking?
Martyn.
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canaletto5
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Joined: Tue Jul 23, 2013 8:43 pm
Location: Derbyshire

Re: Carb Overflow GT550

Post by canaletto5 »

Hi

No, fuel should not run on any tap position other than Prime unless the vacuum is drawing it down when the engine is running. I suspect the fuel tap is faulty. Kev
Tino996
Posts: 19
Joined: Wed Jan 10, 2018 6:41 pm
Location: gatwick

Re: Carb Overflow GT550

Post by Tino996 »

Many thanks Kev. I’ll investigate the tap, and probably replace if not sure.
Cheers
Martyn
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: Carb Overflow GT550

Post by barney01 »

Have a look here for help in tap service
https://youtu.be/qWNyvjaWfz8
NO SMOKE .......NO POKE
asco58
Posts: 122
Joined: Sat Nov 21, 2020 2:24 am
Location: London

Re: Carb Overflow GT550

Post by asco58 »

Tino996 wrote: Thu Nov 04, 2021 11:35 am I have set the float level as per Suzuki shop manual.
What was the specified float height and carb specs in the shop manual you were looking at? Ash
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slosher
Posts: 901
Joined: Fri Sep 23, 2011 6:55 pm
Location: Walsall,Black Country

Re: Carb Overflow GT550

Post by slosher »

asco58 wrote: Thu Nov 04, 2021 7:42 pm
Tino996 wrote: Thu Nov 04, 2021 11:35 am I have set the float level as per Suzuki shop manual.
What was the specified float height and carb specs in the shop manual you were looking at? Ash
The Haynes quotes a height of 25.8mm from the gasket face to the top of the float that's for "L" model also a Suzuki bulletin says 25.76mm
+1 with Kev fuel tap
Cheers Dave
GT750L
GT550L
TL1000 97s
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Loctite Trained Engineer :lol:(since having the Bonnie)
asco58
Posts: 122
Joined: Sat Nov 21, 2020 2:24 am
Location: London

Re: Carb Overflow GT550

Post by asco58 »

I was thinking maybe wrong float height as well because the shop manuals I've seen on the internet quote the J/k model float height of 24.25mm but as Dave says, the correct height for L models is 25.75mm but if the floats have been set to ~25.75mm then you can rule that out.
Optedout
Posts: 219
Joined: Thu Jan 24, 2019 6:56 pm
Location: Worcs

Re: Carb Overflow GT550

Post by Optedout »

If all else fails then it may be worth making sure that all the floats actually float properly
in a bowl of water.
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