Idling problems gt500

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Paulini
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Joined: Sun Mar 10, 2013 4:08 am
Country: netherlands
Suzuki 2-Strokes: 2x GT500 1976

Idling problems gt500

Post by Paulini »

hi guys,

Ive bought a gt500 many years ago. With some time to burn these days i took the engine apart and replaced everything there was to replace, also the crankseals(they were toast, specially the middleone)

Now i am done rebuilding and started it up. The problem is that i can not get the bike to idle. The idle screws are turned right in to the max, airscrew 1 3/4 open, needle at it lowest. It seems it is running rich. inlet rubbers are new, carb to airfilter rubber is also new and it has a foam filter(all original)

I have the following; main jet 97,5 stat jet 30, piston 2,5 and needle 5(h or f my eyes) p17
The carbs are mikuni stamped with 15313 should be a 32mm

When i drive it full open throttle is go’s allright from second gear up. In first doesnt run clean.
Now i had the floatlevel adjusted to 27,3 wich i found in a t500 service manual. Since it isnt running maybe this is wrong? I am finding a lot of different float levels, does anyone know what the right floatlevel is for the above carb?

Also any other tips are appriciated!

Regards,
Paul- Holland
Two Suzuki gt500’s from 1976
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Jaguar
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Suzuki 2-Strokes: 1990 AX100
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Re: Idling problems gt500

Post by Jaguar »

What are symptoms that made you think it runs rich down low?
Be aware that the needle jet gets wallowed out after a lot of time which lets too much gas in, even at idle.
Paulini
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Posts: 11
Joined: Sun Mar 10, 2013 4:08 am
Country: netherlands
Suzuki 2-Strokes: 2x GT500 1976

Re: Idling problems gt500

Post by Paulini »

Mainly because when putting on the choke it gets worse. Also when i rev it in neutral (instant fot) it does not die, it sputters/stutters. And when driving in the upper revs it does run ok.

Hope this helps
Two Suzuki gt500’s from 1976
karl pa
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Suzuki 2-Strokes: GT
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Re: Idling problems gt500

Post by karl pa »

Did you check the carb slides are in the right carbs, cutout toward air box, if slides are in the wrong carbs it will act like that. Trust me I know :oops:
I use oldjapanesebikes.com for info on GT500
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
Paulini
On the street
Posts: 11
Joined: Sun Mar 10, 2013 4:08 am
Country: netherlands
Suzuki 2-Strokes: 2x GT500 1976

Re: Idling problems gt500

Post by Paulini »

karl pa wrote:Did you check the carb slides are in the right carbs, cutout toward air box, if slides are in the wrong carbs it will act like that. Trust me I know :oops:
I use oldjapanesebikes.com for info on GT500

*running to my garage, flashlight in hand and twistingoff top of carb an checking*

You are the man! I have made the same mistake! did not think it could be wrong because of the pinn, but switching left to right it can haha

I have something to do tomorrow and let you know!

How did you found it with your bike?
Two Suzuki gt500’s from 1976
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: Idling problems gt500

Post by karl pa »

I was talking to suzuki shop about it when it just hit us to check. About a year later, they did the same thing. Don't worry it happens alot on suzuki twins.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
Paulini
On the street
Posts: 11
Joined: Sun Mar 10, 2013 4:08 am
Country: netherlands
Suzuki 2-Strokes: 2x GT500 1976

Re: Idling problems gt500

Post by Paulini »

Ah great, thanx for the tip.

Any idea on the float hight?

I have seer ans read 30mm, 29mm, 25,8mm and the 27,3 i used.
Two Suzuki gt500’s from 1976
karl pa
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Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
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Suzuki 2-Strokes: GT
Location: southeast pa

Re: Idling problems gt500

Post by karl pa »

Some don't like my method. I hold the carb upside down, when float tang touches needle valve plunger the float arm should be parallel to carb body. Suzuki shop taught me that way :idea:
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: Idling problems gt500

Post by karl pa »

According to ojb manual, it shows 27.25mm
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
Paulini
On the street
Posts: 11
Joined: Sun Mar 10, 2013 4:08 am
Country: netherlands
Suzuki 2-Strokes: 2x GT500 1976

Re: Idling problems gt500

Post by Paulini »

Thanx, i will swap the pistons of the carbs and post my findings.
Two Suzuki gt500’s from 1976
Paulini
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Posts: 11
Joined: Sun Mar 10, 2013 4:08 am
Country: netherlands
Suzuki 2-Strokes: 2x GT500 1976

Re: Idling problems gt500

Post by Paulini »

Swapped the pistons from the carbs today, total other machine with bottomend power and nicely idling. Again thanx!!
Two Suzuki gt500’s from 1976
Craig380
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Re: Idling problems gt500

Post by Craig380 »

Got to love those easy fixes :up: 8)
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: Idling problems gt500

Post by karl pa »

:up: Great news, the 500 is a nice powerful bike, the other year I was riding with some goldwings who thought I might not be able to keep up, they laughed when I said mine fires every revolution compared to their every other, they weren't laughing when I had no trouble keeping up. (but they did make me ride behind them because the smoke)
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
Paulini
On the street
Posts: 11
Joined: Sun Mar 10, 2013 4:08 am
Country: netherlands
Suzuki 2-Strokes: 2x GT500 1976

Re: Idling problems gt500

Post by Paulini »

Ha ha, the smoke.. i love the smell of burned castrol a747 oil.

Its my first ride/drive on a gt500, really liking it but mij god, at some rpm the thing is a real womanpleaser to put it nicely :wth:

That been said, this one semi ready, just bought me another gt500 yesterday :up:
Two Suzuki gt500’s from 1976
karl pa
To the on ramp
Posts: 490
Joined: Sat Sep 05, 2015 3:14 pm
Country: us
Suzuki 2-Strokes: GT
Location: southeast pa

Re: Idling problems gt500

Post by karl pa »

Paulini wrote:at some rpm the thing is a real womanpleaser to put it nicely
Yep I know what that's like. The triples are rubber mounted engines, not near as bad.
You always need more than one bike, today my GT550 hydrolocked so I pushed it to the side and got out the GT380. (but my wife don't see it the same way :roll: )
Last edited by karl pa on Sun May 03, 2020 5:52 am, edited 1 time in total.
76 GT185
77 GT250
77 GT380
76 GT500
73 GT550
73 GT750
74 GT750
71 T250 scrambler
75 T500 cafe
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