Author Topic: New to me carb issue  (Read 437 times)

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Offline Sdsbassist

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  • Gus, Austin, MN.
New to me carb issue
« on: August 26, 2018, 11:16:56 AM »
So, what would cause one carb slide to not raise when the others do? It lags behind the others for some reason. It starts to raise when the others are about 1/4" up.

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Gus, Austin, MN.
Current Bike:  75 750F

Past bikes: 76 750K - "Iowa Blue",78 750K Craigslist find - "Black Beth;" 77 CB750K Basketcase, with a 75K engine; 1970 Cb750 K1, "Rosa Luxembourg"
74 cb750, 75 cb550, 77 kawa 650, 81 virago 750, 83 virago 920, 80 Honda Twinstar 200, 71 Honda CT70, 1971 Honda CB750 Rat Project "Black Dahlia Bitsa"

Offline ekpent

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Re: New to me carb issue
« Reply #1 on: August 26, 2018, 12:18:54 PM »
 Are they the early style 750 round top carbs ? If so there is a bracket inside of the slide that holds down the needle jet and also holds the larger shaft that pulls the slide up and also where you do your synch adjustment. There is a chance that the bracket may be bent or tweaked. One way to tell is if the slide is removed that shaft is very floppy. Gets tweaked when people force a seized up slide when they are dirty or gummy. Another issue could be that slide is way off on its synch adjustment.
« Last Edit: August 26, 2018, 02:07:09 PM by ekpent »

Offline Sdsbassist

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Re: New to me carb issue
« Reply #2 on: August 26, 2018, 12:55:48 PM »
This is exactly what happened then. The card were gummed up so I'm not surprised that this happened.

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Gus, Austin, MN.
Current Bike:  75 750F

Past bikes: 76 750K - "Iowa Blue",78 750K Craigslist find - "Black Beth;" 77 CB750K Basketcase, with a 75K engine; 1970 Cb750 K1, "Rosa Luxembourg"
74 cb750, 75 cb550, 77 kawa 650, 81 virago 750, 83 virago 920, 80 Honda Twinstar 200, 71 Honda CT70, 1971 Honda CB750 Rat Project "Black Dahlia Bitsa"

Offline ekpent

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Re: New to me carb issue
« Reply #3 on: August 26, 2018, 02:10:08 PM »
 If that bracket is bent and your lucky enough to get the two screws out that hold it and your needle jet then its easy to bend back. I gently used my vise and checked it with a micrometer to a known good one.

Offline Sdsbassist

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Re: New to me carb issue
« Reply #4 on: August 26, 2018, 02:11:25 PM »
Thanks again!

Sent from my SM-N910V using Tapatalk

Gus, Austin, MN.
Current Bike:  75 750F

Past bikes: 76 750K - "Iowa Blue",78 750K Craigslist find - "Black Beth;" 77 CB750K Basketcase, with a 75K engine; 1970 Cb750 K1, "Rosa Luxembourg"
74 cb750, 75 cb550, 77 kawa 650, 81 virago 750, 83 virago 920, 80 Honda Twinstar 200, 71 Honda CT70, 1971 Honda CB750 Rat Project "Black Dahlia Bitsa"