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Author Topic: Carb Adjustment  (Read 2377 times)

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Offline Scott S

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Re: Carb Adjustment
« Reply #25 on: July 12, 2016, 03:19:14 PM »
 You are very, very close. But if it were mine, I'd continue to work on 1 and 2 and get them to match 3 and 4.

 Do you know what/where the idle MIXTURE screws are on the carbs? Not the one big, knurled knob that adjust all four....the individual screws on the carb bodies.

 Where do you have the idle set right now?

 And while we're at it, I'm assuming that the valves were adjusted and the timing set BEFORE you starting syncing the carbs, right?
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Offline flybox1

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Re: Carb Adjustment
« Reply #26 on: July 12, 2016, 08:24:59 PM »
Yeah.  Dont worry about the popping.  The sync is good enough IMO to now start on mixture tuning, as long as all other tuning items are complete.  Youll have to revisit the vacuum sync after you get those carbs off n on several times ;D
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline gbal06

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Re: Carb Adjustment
« Reply #27 on: July 13, 2016, 06:19:45 PM »
I have it all sync up and rides better, but now its a little harder to start up cold.
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Offline Scott S

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Re: Carb Adjustment
« Reply #28 on: July 13, 2016, 06:31:54 PM »
 Somewhat normal for a 550.

 What are your mixture screws set at?
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'17 Triumph Street Scrambler
'81 Yamaha XS650

Offline gbal06

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Re: Carb Adjustment
« Reply #29 on: July 13, 2016, 06:38:37 PM »
to be honest i do not know
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Offline Scott S

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Re: Carb Adjustment
« Reply #30 on: July 14, 2016, 03:19:10 AM »
 It's easy to find out. Just take a screwdriver and lightly seat them. Count the turns. Then just set them back where they were until you report back.

 They are called idle mixture screws and can/should have an effect on how the bike idles as well as the transition to the pilot jets, in the first quarter turn of travel.  They may have something to do with your snapping and popping, but the pods and open exhaust most definitely have something to do with that!
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'71 CB500 K0
'17 Triumph Street Scrambler
'81 Yamaha XS650

Offline gbal06

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Re: Carb Adjustment
« Reply #31 on: July 14, 2016, 09:19:52 AM »
where are the screws located? Do i need to do all 4 carbs or is there just one master screw?
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Offline flybox1

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Re: Carb Adjustment
« Reply #32 on: July 14, 2016, 09:46:15 AM »
Quote from: gbal06 on July 14, 2016, 09:19:52 AM
where are the screws located? Do i need to do all 4 carbs or is there just one master screw?
Location depends on the model of carbs you have.
There is one screw for each carb.  Each will need to be adjusted individually to suit the needs of that carbs idle circuit.

For PD carbs, the screws are located under the carb, along the rim of the bowl.  Turning them OUT makes that carb RICHER.  IN is LEANER.

For other carbs they are located on the sides of the carb bodies.  They are just aft of the carb slide chamber.   #1&2 carb screws are on the left sides of the carb for easy access, and 3&4 are located on the right sides of the carbs for access from the right side of your bike.  Turning them IN will make that carb RICHER.  OUT makes it LEANER.
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline gbal06

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Re: Carb Adjustment
« Reply #33 on: July 14, 2016, 10:01:10 AM »
great I will do it this weekend and let you know.  Thanks
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