Need help reading OEM carb spec sheet

[raerickson]

So this is a first and I am thouroughly cleaning out my carbs and need some help interpretting the spec sheet. I found the sheet for my bike, a 81 gs450.

US 450 models:
Make: Mikuni
Type: BS34SS
Venturi Size: 34mm (1.34 in)
ID number:
ED: 44400
LD, TXD, LF: 44460
Other models: 44110
Idle Speed:
ED, LD, TXD: 1200 +- 50 RPM
Other Models: 1200 +- 100 RPM
Fuel Level:
ED, LD, TXD, LF: 5.0+- 0.5 mm ( 0.20 +- 0.02 in)
Other Models: 6.5 +- 0.5 mm (0.26 +- 0.02 in)
Float Height:
ED, LD, TXD, LF: 23.0 +- 1.0 mm (0.89 +- 0.04 in)
Other Models: 22.4 +- 1.0 mm (0.88 +- 0.04 in)
Main Jet:
ED: 120
Other Models: 115
Main Air Jet:
ED, LD, TXD, LF: 0.7
Other Models: 0.6
Jet Needle:
ED: 5DX87
LD, TXD, LF: 5CDT60
Other Models: 4C2
Needle Jet:
ED, LD TXD, LF: 0-6 (O-6??)
Other Models: Y-6
Throttle Valve:
LF: 95
Other Models: N/A
Pilot Jet:
ED, LD, TXD, LF: 45
Other Models: 17.5
Bypass:
ED, LD, TXD, LF: 1.0, 0.8, 0.9
Other Models: 0.8
Pilot Outlet:
ED, LD, TXD, LF: 0.7
Other Models: 1.1
Float Valve Seat: 2.0
Starter Jet:
ED, LD, TXD, LF: 32.5
Other Models: 30.0
Pilot Screw Setting:
ED, LD, TXD: Preset (2.0 turns out)
Other models: Preset
Pilot Air Jet:
ED: 135
LD, TXD: 145
LF: N/A
Other Models: 1.6

But what I need help with is how far to turn the factory screw settings. Specifically the main jet, the pilot jet, and the air pilot jet. Or do I even need to turn those or should they be all the way in?

I could really use some help guys as I feel like I am in way over my head...

[Suzuki_Don]

So this is a first and I am thouroughly cleaning out my carbs and need some help interpretting the spec sheet. I found the sheet for my bike, a 81 gs450.


But what I need help with is how far to turn the factory screw settings. Specifically the main jet, the pilot jet, and the air pilot jet. Or do I even need to turn those or should they be all the way in?

Main jet, pilot jet & air jet screw all the way in and nip them up tight. The only adjustment is the idle mixture screw (2 to 3 turns out) and float level.

[BassCliff]

Hi,

On your carbs the only adjustment is the mixture screw. All the jets are installed by screwing them in all the way.



If you carbs still have the cap on the mixture screw, it can be removed by drilling a small, very shallow hole in the cap, screw in a small wood screw, then use pliers to pop it out. Be careful NOT to drill down into the mixture screw itself.

Thank you for your indulgence,

BassCliff

[raerickson]

Right here? And is a mixture idle screw and a pilot screw the same thing?

[chef1366]

Right here? And is a mixture idle screw and a pilot screw the same thing?

Yes,
Drill that cap off and under it is what I call the Idle Mixture Screw.