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Constant Velocity Carb. Tuning

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My 2002 Suzuki DR650SE responds slowly to lots of throttle at low rpms. I've increased jet sizes, opened up the air box and raised the needle which has helped. I want the vacuum operated slide to come up quicker and short of possible cutting down the length of the spring I'm not sure how to proceed. Any tips?

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Are you shure thats what you want? The object of a CV carb is to prevent "overcarboration". That is where you have so much throttle area open and RPM so low that there is insuficent air flow to sipon the gas. I think the factory guy that set it up that way knew what he was doing, the only reason we don't have those carbs on "race bikes" is they weigh more.

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You don't have to cut the loops of the spring, just tie them together with some fine wire.

Ride on

Brewster

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You can cut the spring and raise the needle to improve response.

I like brewster's suggestion of using fine wire to shorten the spring too. The carb will work with no spring, but gets to be too rich in rough terrain and can be inconsistent.

James

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Thanks for the replies. I've trimmed some of the spring, increased the size of the vacuum hole in the slide and raised the needle. Because my DR is a California model it has only one needle clip position. I've been machining different thickness delrin spacers to raise the needle. I'm making small changes and doing "seat of the pants" testing. The throttle response continues to improve, but I'm still experimenting.

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