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Discussion Starter #1
The rest of the bike is stock and I got it for $280 and repainted the tank and sidecovers and got everything working but the airbox looked unappealing so I went with UNI pod filters. Stock, the carbs have a 102 main and a 68 secondary main and a plug where the pilot jet is which I believe is pressed in and I haven't tried to remove it. I rode it for the first time yesterday and it is lean almost everywhere. WOT it doesn't rev well then at 7000 rpm it is like a turbo boost. Can I put a new pilot jet in or does that even do anything because it is plugged? What should I go up to on the mains?

1973CB500F, 1980CB750C
 

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the cb750c uses CV carbs which don't respond well to pod filters. If you bought Uni brand foam filters you bought one of the better brands out there. What type of exhaust do you have?

First I would make sure your carbs are clean. Espically the air passages since they are what actually lifts the slide. I would probably go to 105 on the main just to see if that helps.

Also, I belive the pilot jet is not supposed to be plugged but there may be a difference in the C carbs from the F carbs that I am not aware of.
 

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...oh brother.

just put the damn box back on!!!

"...if you're too open-minded, your brains fall out."
 

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Pods are the worse upgrade for a 79-82 CB bike, You need direct lift carbs to be able to use pod filters

22/m
1980 Honda CB750
1972 Oldsmobile 442
 

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Discussion Starter #5
SOB!!!!! So I wasted money on the air filters.....I can't slap the airbox back on because it is just too hideous and I tossed it ;) So I assume that the slide lifts too much at a given throttle position because of the greater air flow? I guess my only option is to mess with jetting. Should have joined this forum before this project,huh.

1973CB500F, 1980CB750C
 

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Discussion Starter #6
I have stock exhaust and the diagrams and both sets of carbs have the plugs installed. Maybe I should unplug them to richen up the pilot circuit.

1973CB500F, 1980CB750C
 

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if your slide was sticking then you wouldn't be running lean you would be running rich.

you can make the carbs work reasonably well with decent pods (uni, K&N) but they will never run as good as velocity stacks or the original airbox. It will also take you a long time to dial them in jetting wise.

Take the bank off, and bench test the slides with compressed air (you only need about 5-10 psi). After that try increasing all the jets 1 jet size. Should begin to help.

the problem with the vacuum carbs is there are not a lot of settings for them.

this is a forum specifically for your bike - do some searches there and see what they say:

http://www.cb750c.com/
 

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you can learn a TON about your bike at cb1100f.net. those guys know the dohc to the last snap ring and bullet connetor. they seem pretty cool too although there i only lurk. i see a few guys from here over there.

boxes shouldn't be too hard to find. i'd replace it. other than that, i thinnk you're stuck fumbling with jetting using stacks (which is essentially what's "in" the airbox).

good luck.

"...if you're too open-minded, your brains fall out."


Edited by - catboy on Feb 08 2008 09:03:19 AM
 

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I've got a 79 CB750 airbox in my attic if you need one. However, they can be made to run with pods. It just takes a lot of time.

Gas Right, Clutch Left
 

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Discussion Starter #10
I am going to give it a reasonable try with some 105's, 107's, and 70 or 72's and try removing the pilot jet plug to richen the pilot circuit.

1973CB500F, 1980CB750C
 
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