78' GS750 Carburator Hose question

[Shred Astaire]

Hi Folks,

I'm getting close to starting up a garage sale purchase 1978 GS750E and wanted to know where the vacuum from the petcock connects with the carb system.

Here are two pictures of my carbs and I put a blue cap on the port I believe is the vacuum port. Also, why are two ports plugged on the right
side?

https://kenmurray.smugmug.com/1978-Suzuki-GS750/i-kLxWtQG/A

https://kenmurray.smugmug.com/1978-Suzuki-GS750/i-PP3JPBB/A

Thanks,
Shred

[allojohn]

Nope, #3 is the vacuum port, hoses on 2 & 4 should vent to calm air over the airbox.
3 & 4 ports are blocked because someone didn't know what they were doing.

[Rich82GS750TZ]

This very well could be the most common question asked on the forum, it certainly is very common, especially when someone gets a GS that doesn't run or runs poorly. It sure would be nice if someone would fix the pics in this link, or create a new article with clear picture of where the hoses go on Both VM and CV carvb. I know I've seen both, so they do exist. I'm just not able to locate them. Not planning to take my carbs off any time soon, or I would do it myself for the CVs. The other broblem is getting files placed on BikeCliff's, which, for whatever reason, seems difficult. Not a Criticism of Bikecliff's site nor the fine folks who have made it the great resource that it is. Lord knows, it's become my favorite website next to this one.

http://members.dslextreme.com/users/storagecliff/images/hose_locations.html

[Shred Astaire]

Nope, #3 is the vacuum port, hoses on 2 & 4 should vent to calm air over the airbox.
3 & 4 ports are blocked because someone didn't know what they were doing.

Thank you John!!!

[Shred Astaire]

Nope, #3 is the vacuum port, hoses on 2 & 4 should vent to calm air over the airbox.
3 & 4 ports are blocked because someone didn't know what they were doing.

He drilled (6) 5/8" holes thru the bottom of the air box that I sealed up. I don't know anything about carb settings but I have a feeling these won't be dialed in exactly

[allojohn]

Start with the fuel screw (under the carb) at 7/8th of a full turn out and the air jet at 1.5 out. Adjust the airs screws using the highest idle method. Once you have that done you'll need a manometer to balance the carbs.

But all of this may be in vain if you haven't adjusted the valves or cleaned the carbs yet. The 24hr carb dip method is non-negotiable, and while you're there you find out what size pilot/main jets you have.

[Shred Astaire]

Start with the fuel screw (under the carb) at 7/8th of a full turn out and the air jet at 1.5 out. Adjust the airs screws using the highest idle method. Once you have that done you'll need a manometer to balance the carbs.

But all of this may be in vain if you haven't adjusted the valves or cleaned the carbs yet. The 24hr carb dip method is non-negotiable, and while you're there you find out what size pilot/main jets you have.

Thanks John!!

[Shred Astaire]

Start with the fuel screw (under the carb) at 7/8th of a full turn out and the air jet at 1.5 out. Adjust the airs screws using the highest idle method. Once you have that done you'll need a manometer to balance the carbs.

But all of this may be in vain if you haven't adjusted the valves or cleaned the carbs yet. The 24hr carb dip method is non-negotiable, and while you're there you find out what size pilot/main jets you have.

Hey John,

I'm going to take the carbs off today and soak them for a couple of days in white vinegar. I have 4 into one exhaust but I found some pristine stock pipes in Winnipeg that should be here by next Friday. What jets will I need for the stock pipes?

Thank you!

[allojohn]

Hey John,

I'm going to take the carbs off today and soak them for a couple of days in white vinegar. I have 4 into one exhaust but I found some pristine stock pipes in Winnipeg that should be here by next Friday. What jets will I need for the stock pipes?

Thank you!

White vinegar likely won't be powerful enough, get a gallon can of carb dip (24 hrs) - Berrymans, Napa or whatever...
Stock pipes and stock air box - 102.5 main jet, 15 bleeder (pilot) jet will work fine.
Switching from/to 4-1 and the stock pipes doesn't make a much of a difference that I can tell - I change every so often and never mess with the jetting.

[Big T]

http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf

Order your O rings and follow this tutorial

[Shred Astaire]

White vinegar likely won't be powerful enough, get a gallon can of carb dip (24 hrs) - Berrymans, Napa or whatever...
Stock pipes and stock air box - 102.5 main jet, 15 bleeder (pilot) jet will work fine.
Switching from/to 4-1 and the stock pipes doesn't make a much of a difference that I can tell - I change every so often and never mess with the jetting.

Thank you John!

[Shred Astaire]

http://members.dslextreme.com/users/...rb_rebuild.pdf

Order your O rings and follow this tutorial

Thank you Big T! I don't feel confident enough to do a full rebuild. I barely know what I'm doing.

[Shred Astaire]

http://members.dslextreme.com/users/...rb_rebuild.pdf

Order your O rings and follow this tutorial

I just looked over that PDF. Sweet! d.o.w.n.l.o.a.d.i.n.g

[chuck hahn]

Berrymans for 24 hours. take the basket out and you can put 2 bodies in the can at once. use bread tie wire and wire the jets to one of the bowl screws hole.

[Big T]

Thank you Big T! I don't feel confident enough to do a full rebuild. I barely know what I'm doing.

Barely know what you're doing, but willing to bang your head against the wall instead?

The GSR exists to pass our accumulated mistakes on to you, so that you can do things the right way

Go here -https://www.thegsresources.com/_forum/showthread.php?196338-New-Members-CLICK-HERE!! (it's the sticky in the GS Owners forum)

Read thru everything -especially the Top 10 Newbie Mistakes (made just for you!) and the BassCliff website. Get yourself a factory service manual there and check out the valve adjustment, carb sync and electrical tutorials. Yes, some of links are broken

Ready? Get yourself an egg carton, a can of carb dip, a JIS screwdriver, small metric sockets, an impact driver and order up a set of O rings for the carbs and intake boots.

Aaaand, Go!