Author Topic: 1978 CB750 slide needle shim installation  (Read 3529 times)

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Offline lucky

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1978 CB750 slide needle shim installation
« on: January 25, 2012, 10:29:06 AM »
I was not successful at getting this 1977,1978 carb to respond to pods or stacks.
I have come to the conclusion that a different tapered needle would have to be fitted.
Even that may not work.

They did respond to shims and jet changes but only temporarily at the expense of carboned up plugs. (It ruins the plugs.)

« Last Edit: April 15, 2012, 09:58:22 AM by lucky »

Offline lucky

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Re: 1978 CB750 slide needle shim installation
« Reply #1 on: April 24, 2012, 06:15:05 PM »
I have installed the stock air filter and air box.

To my surprise the stock idle jet would still not work because of the only non stock part...the 4 into 2 into 1 exhaust with baffle.

I took the carbs back off and put in #42mm idle jets and now it idles great with good throttle response. The mixture screws are turned out about 7/8 of a turn.

So it is a 1978 CB750.
4 into 2 into 1 exhaust with metal baffle.
mixture screw about 7/8 turn out.
No shims on the needles.
Main jet #120.
Stock OEM filter and stock air box.
Good throttle response ,easy starting.