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bst 34mm air/fuel mixture
- 79kz1000*
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27 Sep 2011 17:06 #479998
by 79kz1000*
79 kz 1000 ltd
76 kz 900
bst 34mm air/fuel mixture was created by 79kz1000*
I have a set of bst34 carbs, was wanting to know what the factory setting is for the air/fuel mixture. How many turns in or out they should be????
79 kz 1000 ltd
76 kz 900
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- gd4now
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- Denco where did you go?
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27 Sep 2011 19:36 - 27 Sep 2011 19:37 #480028
by gd4now
1977 KZ650 B1
Pods and Denco header
OLD KAW OWNERS SMILE ALOT
Replied by gd4now on topic bst 34mm air/fuel mixture
IIRC those carbs have a forward lean to them. They were intened for bikes where the engine leans forward much more so than the KZs do. You may have issues with float / fuel height, as the bowl sits level to the ground on the forward leaning engine bikes. It most likely will not do so on the kz, and may lean to the back of the bike.
As to air/fuel screw adjustments here is some info for the carbs used on 86-88 GSX-R1100
Type: BST34SS
Main Jet: 130
Main Air Jet: 0.6mm
Jet Needle U.S: 5D29 U.K: 4D13-3
Needle Jet U.S: P-2 U.K: O-9
Pilot Jet U.S: 32.5 U.K: 42.5
Pilot Air Jet U.S: 135 U.K: 150
Pilot Screw setting U.S: Preset U.K: Preset (2 turns out)
Starter Jet (choke): 45
Float Height: 14.6mm (+/- 1mm)
Instructions on setting float height
To check and adjust the float height, carry out the following manner:
* Invert the carburetor body
* Gradually lower the float and observe the clearance between the float tongue and the end of the needle valve. When the tongue just begins to contact the end of the needle valve, stop lowering the float and hold it. Then measure the height (A) from the float chamber mating surface using vernier calipers.
Float height 14.6 +/- 1mm
* Bend the tongue as necessary to bring the height within the standard range
As to air/fuel screw adjustments here is some info for the carbs used on 86-88 GSX-R1100
Type: BST34SS
Main Jet: 130
Main Air Jet: 0.6mm
Jet Needle U.S: 5D29 U.K: 4D13-3
Needle Jet U.S: P-2 U.K: O-9
Pilot Jet U.S: 32.5 U.K: 42.5
Pilot Air Jet U.S: 135 U.K: 150
Pilot Screw setting U.S: Preset U.K: Preset (2 turns out)
Starter Jet (choke): 45
Float Height: 14.6mm (+/- 1mm)
Instructions on setting float height
To check and adjust the float height, carry out the following manner:
* Invert the carburetor body
* Gradually lower the float and observe the clearance between the float tongue and the end of the needle valve. When the tongue just begins to contact the end of the needle valve, stop lowering the float and hold it. Then measure the height (A) from the float chamber mating surface using vernier calipers.
Float height 14.6 +/- 1mm
* Bend the tongue as necessary to bring the height within the standard range
1977 KZ650 B1
Pods and Denco header
OLD KAW OWNERS SMILE ALOT
Last edit: 27 Sep 2011 19:37 by gd4now.
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- roy-b-boy-b
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27 Sep 2011 19:37 #480030
by roy-b-boy-b
1979 LTD Street Fighter.1977 KZ1000
Replied by roy-b-boy-b on topic bst 34mm air/fuel mixture
What ever the setting is,it is only a base setting. So why don't you start at 1 3/4 and with a hand held tach turn them in until you reach max rpm then back them off 1/8 turn.
You can't see the minute rpm changes with the bikes tach.
I know there will be a lot of people will jump all over this answer telling you the correct way to do it but this is basic tuning and you need to start some where and basic is expeident.
You can't see the minute rpm changes with the bikes tach.
I know there will be a lot of people will jump all over this answer telling you the correct way to do it but this is basic tuning and you need to start some where and basic is expeident.
1979 LTD Street Fighter.1977 KZ1000
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- 79kz1000*
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27 Sep 2011 22:52 #480079
by 79kz1000*
79 kz 1000 ltd
76 kz 900
Replied by 79kz1000* on topic bst 34mm air/fuel mixture
Thanks for the help guys
79 kz 1000 ltd
76 kz 900
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- Polar_Bus
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28 Sep 2011 16:09 #480234
by Polar_Bus
rule of thumb with air screws is that if you are achieving good engine behavior at idle and accelerating just off idle with the air screws set between 1.5 to 2 turns from seated you have good low speed jetting. If you have to adjust the air screws beyond the 1.5 to 2 turn parameters you need to possibly make a pilot jet change .
Bikes:
'84 GPz1100
'06 HD Fatboy
Replied by Polar_Bus on topic bst 34mm air/fuel mixture
79kz1000* wrote: Thanks for the help guys
rule of thumb with air screws is that if you are achieving good engine behavior at idle and accelerating just off idle with the air screws set between 1.5 to 2 turns from seated you have good low speed jetting. If you have to adjust the air screws beyond the 1.5 to 2 turn parameters you need to possibly make a pilot jet change .
Bikes:
'84 GPz1100
'06 HD Fatboy
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