Tiny Air Bleed Jet - Smaller size than Main
- Thread starter haze324
- Start date
V
Guru
The original G carb came with a fixed .040 hole for the air bleed. It was not adjustable.
Some dealers and after market drilled and modified these carbs so the air bleed jet could be changed. Depending on who (Davinci) did your carb that air bleed may not be a S&S jet. Very well may be Mikuni sized.
Late G model carbs produced by S&S had a standard size S&S jet for the air bleed it was stock as .040.
On my last G from XXX carbs I was running a 33 int, 78 main, and a 64 air bleed. This was with a cam in the motor as well.
Might go to the HD shop and see if that is a Mikuni jet as it does not appear to be a S&S style or call Davinci. :2thumbs:
Some dealers and after market drilled and modified these carbs so the air bleed jet could be changed. Depending on who (Davinci) did your carb that air bleed may not be a S&S jet. Very well may be Mikuni sized.
Late G model carbs produced by S&S had a standard size S&S jet for the air bleed it was stock as .040.
On my last G from XXX carbs I was running a 33 int, 78 main, and a 64 air bleed. This was with a cam in the motor as well.
Might go to the HD shop and see if that is a Mikuni jet as it does not appear to be a S&S style or call Davinci. :2thumbs:
Well it ran fast as hell!!!!
I spoke to Bob and had recommended 32/76 60 air bleed. I have a 107, stock 2n1 kerker and .600 cam living in Miami. He said have the mixture out about 2 full turns and go from there. So I ordered the jets from him and when I saw the smaller air bleed it really thru me off. Gotta find what brand it is.
Good news is with those jets and settings mixture and accel out 2 full turns the bike started right up and doing two quick runs around the block the Dog is smoking fast. Whatever it has or is ---- it works. I'll spend the next few days tuning it and hunting down the air bleed jet.
Thanks fellas.
I spoke to Bob and had recommended 32/76 60 air bleed. I have a 107, stock 2n1 kerker and .600 cam living in Miami. He said have the mixture out about 2 full turns and go from there. So I ordered the jets from him and when I saw the smaller air bleed it really thru me off. Gotta find what brand it is.
Good news is with those jets and settings mixture and accel out 2 full turns the bike started right up and doing two quick runs around the block the Dog is smoking fast. Whatever it has or is ---- it works. I'll spend the next few days tuning it and hunting down the air bleed jet.
Thanks fellas.
john sachs
Well-Known Member
S&S jet sizes are in thousands. I would go with a .0595" air bleed. You can use a # 53 drill bit and enlarge the jet. I send 99% of my S&S carbs out with that size air jet.
For those who don't have a replaceable air jet, you can drill out the .041" hole on the left side of the carb with a #19 drill bit, and tap with a 5MM x 0.8 tap. This will enable you to use a Mikuni main jet, and NOT have to remove the float bowl to change the air jet.
I do this even when there's a removable air jet inside the carb. Remove the internal air jet, plug with a 5/16 threaded plug, and install the external Mikuni jet drilled with the size you want. :2thumbs:
John
For those who don't have a replaceable air jet, you can drill out the .041" hole on the left side of the carb with a #19 drill bit, and tap with a 5MM x 0.8 tap. This will enable you to use a Mikuni main jet, and NOT have to remove the float bowl to change the air jet.
I do this even when there's a removable air jet inside the carb. Remove the internal air jet, plug with a 5/16 threaded plug, and install the external Mikuni jet drilled with the size you want. :2thumbs:John
John thanks man. I just ordered a .0595 jet (that hopefully will fit)......next step is coming to you to bump up compression :2thumbs:
Last edited:
Staffy
Active Member
John - your approach sounds very interesting. Do you have a pic on where exactly you drill this hole on the left side. (Is there a particular air passage that the air-bleed jet must meet?)S&S jet sizes are in thousands. I would go with a .0595" air bleed. You can use a # 53 drill bit and enlarge the jet. I send 99% of my S&S carbs out with that size air jet.
For those who don't have a replaceable air jet, you can drill out the .041" hole on the left side of the carb with a #19 drill bit, and tap with a 5MM x 0.8 tap. This will enable you to use a Mikuni main jet, and NOT have to remove the float bowl to change the air jet.
John
Many thanks
Staffy
john sachs
Well-Known Member
Just finished this carb for Trotta's Thunder Design. You can clearly see the air jet, and area it's in. :2thumbs:
John
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Staffy
Active Member
Many thanks John n NICE work...:2thumbs::2thumbs::2thumbs:
Am working on a bobber build, tried something new.....went for an "ultima" R2 carb (a super E knock off)...with them its a hit or miss. Needless to say I liked the idea that it was - polished and came pre bored for a thunder jet should I choose to install one.....and the $$$, not so bad. Still in the build stage...but on the lift it runs good...:lol::lol:
To my surprise, as I was inspecting the carb over the weekend I found an additional screw on the left side - yes, you guessed right, they had pre-bored the air passage so one could install the air-bleed externally, quite impressive. The only draw back it was for the mini - Mikuni jets.
john sachs
Well-Known Member
Thunderjet use Mikuni main jets for air, and jet in the Thunderjet. No draw back. About the only ones that fit.
John