Your video is interesting, and you are correct about many multi-cylinder bikes using slightly richer jetting for the middle cylinder, or cylinders. You find this especially in the Kawasaki triples. Where I think you are incorrect, is your description of this feature on the GS750 using VM26 carbs. You appeared to be describing enrichening the middle two jets by turning the slider adjusting nut/grub screw on top of the carb. All this does is increase the fuel mix into the engine, just the same as if you twisted the throttle. You have actually used the slider carb synch adjustment, not any enrichener adjustment, as this not only lifts the needle, it also lifts the slide (which increases the air input). When you come to balance the carbs, whatever adjustment you did on that grub screw on top of the carb, you will have to move again to get all four carbs sliding in synch, giving equal vacuum on your gauges. The AIR SCREW, which is on the side of the carb, meters the air in the mixture at idle, and as the throttle is opened, this mix becomes less and less important to the overall mixture, with the needle jet taking over prominence. If you want to enrichen the middle two cylinders, it would have to be by changing the position of the needle circlip, taking the needle up by one notch. I'm not sure the bike would run well if you did that on just the two middle cylinders. The PILOT SCREW, the one underneath the carb, is not really a fuel adjustment, but meters the total AIR/FUEL mix from the AIR SCREW into the carb venturi, and is also predominantly a tickover adjustment, although this mix itself starts to get mixed with the needle/slide mix of air/fuel, as you open the throttle. This is why it's important to get the PILOT SCREW right. On all US-spec VM carbs, the factory marked the PILOT SCREW head with a dot at one side of the screw slot, and also marked a line on the carb body, for that side of the screw slot to line up to. It usually lines up before one complete turn out, from lightly seated.
Wow -that's pretty much the best explanation of the function of both (AIR & PILOT Screw) i was looking for as to set up my GS 750 SUZUKI nicely -thanks so much for that info !
My GS750 came California smogged in '79. It was almost unrideable in that tune. The air/idle screws were painted/sealed. It took overnight paint thinner to correct. I found a Mikuni manual that had the non-smog specs for jet sizes and needles for the 750. I ordered needles, needle jets, main jets etc right from the book. Once those were installed and a good carb sync it unlocked the greatness of the bike.
Nice work. I liked the old Tillotson carbs. Those things were simple to work on. Not many bikes had them, but Briggs and Stratton used to put them on all their motors, even the racing motors.
Great video mate, Just wondering what the end measurements you set the Jet Needles at in the end. I caught that there was only a 10 thou difference between inner 2 and outer 2, but what was the over all measurement on your ruler. Cheers 🍻
Found pilot jet broke n stuck in #3 . years of hassel. Now year later havnt put it in yet. Been my exuse to do other mods. Missed the local burnout contest 2 year now.
Man I need you help on my gs750 project! I rebuilt them just like you watching your videos an cant seem to get it right! An one carb is not geting fuel
TY for making 12 min of my day not boring man 👍. the bike looks sweet. can't wait to see the Barf Party autopsy . i'm really curious to see what failed. a porn studio in FL? noooooo. 🤣🤣🤣 next you'll tell us theres strip clubs in FL. lol. good vid
Hi bro so im running PODs on my Gs 750 i hate them as i bought the bike like that. Im struggling getting my carbs to operate properly, should i tape up the pods? I have my fuel screws at 1turn out and air at 1.5 out. What would u suggest i set the screws to bro? Thanks man
What does the needle do? What's the point on adjusting them? I have this motorcycle and I'm learning by myself how to fix it ... It spends lot of gasoline and burns spark plugs so quickly so I'm going to change those things inside of the carburetor (I bought some reparation kits on the internet) thanks for your video :D
Please help. I just bought a gs750 and have spent the last 2 weeks getting it running well. Took it for a ride and it bogs at 80-100% throttle. The rest of the throttle range is great and has good power. Does this mean my main jet is too big?
I started out with the fuel screws at 2.5 to...as always...the air screw at 1.0 to and adjusted from there starting with the inner 2 carbs and see how they responded...ended up all air at 1.5 to and fuel at 2.5 out
@@shelby.daytona6890 thank you I'm a newbie with motorcycles. I bought my first bike a few months ago, it's a 79 Suzuki GS750L I've torn down the carbs and cleaned them and put em back together just wanted some advice. Thanks again!😁
@@jessepaul9774 new spark plugs are key in 5000 miles you can pull the and read them for how the mix in running...there's plenty of I formation on how to read the plugs...
hey Shelby ... what exactly is the reason for cylinder 2 and 3 running richer ? i changed the plugs out on my 1998 1200 suzuki bandit other day .. i noticed plugs from 1 and 4 were a nice brown colour and 2 and 3 were black .. just wondered why 2 and 3 need to run richer?
On an air cooled 4 cylinder the 2 middle cylinders run hotter due to less airflow to cool them...running richer jets means more fuel to help with cooling
Your video is interesting, and you are correct about many multi-cylinder bikes using slightly richer jetting for the middle cylinder, or cylinders. You find this especially in the Kawasaki triples. Where I think you are incorrect, is your description of this feature on the GS750 using VM26 carbs. You appeared to be describing enrichening the middle two jets by turning the slider adjusting nut/grub screw on top of the carb. All this does is increase the fuel mix into the engine, just the same as if you twisted the throttle. You have actually used the slider carb synch adjustment, not any enrichener adjustment, as this not only lifts the needle, it also lifts the slide (which increases the air input). When you come to balance the carbs, whatever adjustment you did on that grub screw on top of the carb, you will have to move again to get all four carbs sliding in synch, giving equal vacuum on your gauges. The AIR SCREW, which is on the side of the carb, meters the air in the mixture at idle, and as the throttle is opened, this mix becomes less and less important to the overall mixture, with the needle jet taking over prominence. If you want to enrichen the middle two cylinders, it would have to be by changing the position of the needle circlip, taking the needle up by one notch. I'm not sure the bike would run well if you did that on just the two middle cylinders. The PILOT SCREW, the one underneath the carb, is not really a fuel adjustment, but meters the total AIR/FUEL mix from the AIR SCREW into the carb venturi, and is also predominantly a tickover adjustment, although this mix itself starts to get mixed with the needle/slide mix of air/fuel, as you open the throttle. This is why it's important to get the PILOT SCREW right. On all US-spec VM carbs, the factory marked the PILOT SCREW head with a dot at one side of the screw slot, and also marked a line on the carb body, for that side of the screw slot to line up to. It usually lines up before one complete turn out, from lightly seated.
Wow -that's pretty much the best explanation of the function of both (AIR & PILOT Screw) i was looking for as to set up my GS 750 SUZUKI nicely -thanks so much for that info !
This is awesome content mate. Love to see people work and explain on a bike and then start a 40 year old bike like brand new. Awesome work mate
My GS750 came California smogged in '79. It was almost unrideable in that tune. The air/idle screws were painted/sealed. It took overnight paint thinner to correct. I found a Mikuni manual that had the non-smog specs for jet sizes and needles for the 750. I ordered needles, needle jets, main jets etc right from the book. Once those were installed and a good carb sync it unlocked the greatness of the bike.
Hi, do you have a link for that manual?
Currently giving this same treatment to a 79xs750 that’s sat on its side stand since 1980
Nice work. I liked the old Tillotson carbs. Those things were simple to work on. Not many bikes had them, but Briggs and Stratton used to put them on all their motors, even the racing motors.
I had a 79 GS750 and the carbs were made by Mikuni. Stock was 26 mm but I changed them out to 29mm smoothbores. Ran much better.
Great video mate, Just wondering what the end measurements you set the Jet Needles at in the end. I caught that there was only a 10 thou difference between inner 2 and outer 2, but what was the over all measurement on your ruler.
Cheers 🍻
carb work is always fun! Great vid
hat down, excellen good job on a carburetors which is extremely hard to get on properly working (handle with old bikes, meet such issues every day)
Found pilot jet broke n stuck in #3 . years of hassel. Now year later havnt put it in yet. Been my exuse to do other mods. Missed the local burnout contest 2 year now.
Four times the fun, yay.
What carbs are these? I have searched the internet and can’t find it. I need the correct carb kit for these carbs 🙄
Man I need you help on my gs750 project! I rebuilt them just like you watching your videos an cant seem to get it right! An one carb is not geting fuel
Check the crossovers from one carb to the next and double check your float jeight and that the needles aren't stuck closed
NOT THE BEER!!!
Hey there, I don't know if you are still active for comments, but do you remember where you bought the carb kits from?
Parts unlimited
God bless my 750
TY for making 12 min of my day not boring man 👍. the bike looks sweet. can't wait to see the Barf Party autopsy . i'm really curious to see what failed. a porn studio in FL? noooooo. 🤣🤣🤣 next you'll tell us theres strip clubs in FL. lol. good vid
Great vid
Hi bro so im running PODs on my Gs 750 i hate them as i bought the bike like that. Im struggling getting my carbs to operate properly, should i tape up the pods? I have my fuel screws at 1turn out and air at 1.5 out. What would u suggest i set the screws to bro? Thanks man
2.5 turn out on the fuel and 1.5 on the air...
What does the needle do? What's the point on adjusting them?
I have this motorcycle and I'm learning by myself how to fix it ... It spends lot of gasoline and burns spark plugs so quickly so I'm going to change those things inside of the carburetor (I bought some reparation kits on the internet) thanks for your video :D
It depends on what needle your talking about
@@shelby.daytona6890 the ones that you're talking about at 8:40 :D (pd; thanks a lot for replying)
That needle meteres the fuel at 1/4 to full throttle...has no effect on idle to 1/4 throttle
@@shelby.daytona6890 thanks you so much
Beep Beep!!!
Please help. I just bought a gs750 and have spent the last 2 weeks getting it running well. Took it for a ride and it bogs at 80-100% throttle. The rest of the throttle range is great and has good power. Does this mean my main jet is too big?
Most likely...if you roll off slightly and it accelerates your too rich...we call it fat on the main jet
Found pilot jet in my parts 550 is same on 750
Shut up Akaso, you're being needy lol.
The Suzuki sounds great BTW
Curious what you set the air and fuel mixture too? I'm having trouble finding information on the settings.
I started out with the fuel screws at 2.5 to...as always...the air screw at 1.0 to and adjusted from there starting with the inner 2 carbs and see how they responded...ended up all air at 1.5 to and fuel at 2.5 out
It's all pretty much by ear...how does the engine respond to the change...only change 1 thing at a time...1 variable
@@shelby.daytona6890 thank you I'm a newbie with motorcycles. I bought my first bike a few months ago, it's a 79 Suzuki GS750L I've torn down the carbs and cleaned them and put em back together just wanted some advice. Thanks again!😁
@@jessepaul9774 new spark plugs are key in 5000 miles you can pull the and read them for how the mix in running...there's plenty of I formation on how to read the plugs...
@@shelby.daytona6890thanks again, hope to have it up and running soon.
Hey Shelby thanks for the shout out! Changed the Instagram to lonestar.48
hey Shelby ... what exactly is the reason for cylinder 2 and 3 running richer ? i changed the plugs out on my 1998 1200 suzuki bandit other day .. i noticed plugs from 1 and 4 were a nice brown colour and 2 and 3 were black .. just wondered why 2 and 3 need to run richer?
On an air cooled 4 cylinder the 2 middle cylinders run hotter due to less airflow to cool them...running richer jets means more fuel to help with cooling
Same applies to more modern liquid cooled carbed bikes just not as drastic
Hey ive got a GS750 and im having some backfiring issues, any way i could ask you some questions?
Sure...
Backfiring would be a lean mixture I'm guessing ..??
This could be a much better video without the loud, annoying and irrelevant music at the beginning
This is sending me to sleep