‘75 GT550 carburetor questions

[pgb123]

Got it. Thanks! Is it the same gasket that goes on the float bowl drain screw?

[GTandcbr]

Not sure tbh any washer will do as long as it's soft to seal it against air getting in.

[pgb123]

Thank you again. For some reason, that part is not identified in the parts diagram on Partzilla.

[GTandcbr]

https://m.ebay.co.uk/itm/New-OEM-Suzuki ... r=1&_rdt=1" onclick="window.open(this.href);return false;

[dorT500]

Thank you again. For some reason, that part is not identified in the parts diagram on Partzilla.

In partszilla's defense , since I use them so often to get the best pricing and then buy from them or have the Suzuki dealership near me match or beat their price (do it all the time) with no delivery charge but tax is paid, here is the washer gasket in their parts fiche. Different factors determine whether I use them or the dealership.

If you have other parts to order besides that gasket washer and if you have a Suzuki dealership near you, motorcycle or even a Suzuki Marine dealer, see if they will match or beat the best prices you find online and then compare local tax versus delivery from an online source, etc. The dealership I use does not charge me anything (not even hidden in the price) for delivery

[pgb123]

Ah hah! I was looking at the thing backwards. Story of my life!

[pgb123]

What's the proper standard clip position on the needle? The service manual says 3rd from top groove, but it also says the float height should be 24.25 mm while the service bulletin says the float height for the GT550L should be 22.75. Just want to make sure.

[GTandcbr]

Stock clip position is no 3.
Float level is 25.75mm according to the Suzuki carb manual
The 24.25 figure is for single carb J K models

[pgb123]

Thank you for that! Where is the clip position indicated? Is it the same for all standard GT550s?

[GTandcbr]

Clip position on 550 always number 3. However this is made to be adjustable for a reason. Many things can affect the mixture like ambient air temperature and altitude and the way the bike is ridden. If you find the bike runs lean you can lower the clip to make it richer or if it runs too rich raise the clip to make it run leaner.

[pgb123]

Thanks again. That's the manual where it shows the 24.25 float height. I realize that's for a different year machine. That's why I wasn't sure the reference for the clip height was necessarily relevant to my machine. In any event, thanks for confirming it is. I'm eager to get these carbs back together and see if I did everything correctly!

[pgb123]

Ok. Everything’s back together. Bike runs! A couple of problems, however. First, it idles high. I lowered the throttle valve stop screw to lower the idle speed, problem is, the pulley bottoms out before it hits the screw with idle around 2,500-3,000 rpm. I can force the pulley down to hit the screw and bring the idle down to 1,000, but it won’t stay there. Can anyone suggest how I might adjust the tension in the pulley?

Also, since I’ve owned the bike, I’ve been befuddled by a leaking petcock. I replaced it, changed all the gaskets, tried other fixes, but it still leaks. I think I’ve finally figured out where it’s leaking from. Gas spits out of the small hole where the vacuum gasket is. See attached pics. Why is this and what can I do?

[GTandcbr]

Okay firstly the carbs. It sounds like the throttle valves (or it could be just one of the valves)are not balanced and resting on the bottom,see the 'assembly and adjustment section of the carb manual i sent you,the measurements are in there.
Secondly, the petcock, that probably leaking because the piston attached to the diaphragm is not returning to seal the petrol off. Here is a youtube to help
https://youtu.be/qWNyvjaWfz8" onclick="window.open(this.href);return false;

[pgb123]

Thanks for getting back to me. I did balance the carbs per the manual. The trouble I had with that was two-fold. Firstly, in checking the distance from the lower end of the valves and the main bore, I used a feeler gauge. The gauge, however, is flat and the bottom of the bore is curved, so I guestimated a little bit. Then when doing the final adjustment, I did have to lower the other valves, to make sure they all lined up. I'll pull them and try again.

Regarding the petcock, to be clear, the petcock only leaks when the engine is running, so the piston must be sealing when there's no vacuum.

[dorT500]

That diaphragm looks like it is toast to me. All it takes is one tiny, minuscule breech/leak to render it useless and it appears there are several in yours?