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Bench Syncing Carbs for a CB750A

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birdmannn101

Bench Syncing Carbs for a CB750A

A few years back when I synced a CB750K3 carb I started by inserting a drill bit in the bottom of the master carb throttle sleeve and adjusting the other 3 to the same height. Since it has been a few years and I am trying to bench sych a hondamatic 750 carb that someone took apart and tried to put back together, I thought I would check out you tube videos to refresh my mind. All the videos showed syncing the choke plates, not the throttle valves.

So, checked with a friend and he said I was correct in syncing the throttle slides with the needle on the bottom. The master carb is #2 carb but it doesn't look like it is seated. In fact all the carbs are not seated. I turned the idle screw all the way out and they are still not seated. (See pictures).

My question is: Did he screw this up too and how do I get the valves to seat?

http://i1135.photobucket.com/albums/m637/birdmannn101/Hondamatic%20CB750A/number2carbcloseup_zpsb6e14caf.jpg

http://i1135.photobucket.com/albums/m637/birdmannn101/Hondamatic%20CB750A/number2carb_zps05dfaa50.jpg

http://i1135.photobucket.com/albums/m637/birdmannn101/Hondamatic%20CB750A/number3and4carb_zps363b9db0.jpg

66 S90
64 C102
65 C100
65 CT200 Trail 90
74 CB350Four
73 CB750K3
76 CB750A
03 VTX1300S
Bicycle with HF engine

TOOLS1

Re: Bench Syncing Carbs for a CB750A

Administrator

That's correct. Any lower, and it would not be able to run.
TOOLS

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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)

birdmannn101

Re: Bench Syncing Carbs for a CB750A

Thanks for getting back to me on this. If anyone should know, it would be you with all those 750's. I guess instead of using a drill bit to bench sync the carbs I'll use a toothbrush. I never realized that they were open that much at idle. Guess the age is creeping up on me. Thanks again Tools...Dan

66 S90
64 C102
65 C100
65 CT200 Trail 90
74 CB350Four
73 CB750K3
76 CB750A
03 VTX1300S
Bicycle with HF engine