Originally Posted by Thelastmoheigan
Well pluged the hose going to the air box and plug the vac line controling the valve but still pop pop could have exaust leak has anyone else run staight pipe with an H pipe inbetween for balance.
If I understand correctly, you plugged the large hose going from the valve to the airbox, and the small vacuum line to the rear carb. That should completely disable the system. I just removed mine, capped off the fittings on the head, capped off the fitting on the rear carb, and plugged the hole in the bottom of the airbox.
I don't recommend any modifications to the stock system, The main reason most people do that is for more noise. That large chamber under there is specifically designed to balance the system. It has a complex inner structure, it is not just a simple crossover. By removing it you will lose power, and will make it more difficult to tune properly over the entire rpm range. If more noise is what you want, I suggest going with an aftermarket exhaust system designed for the bike. You will still lose power, but the system will still be balanced and easy to tune. The stock intake, engine, and exhaust are a precisely engineered system, designed to work together for best performance for normal riding. Some modification is possible, but I suggest before making any modifications that you thoroughly research what you want to accomplish, and what will be required to do it. Also, modifications from stock will not fix a poorly running bike, it needs to be running right to begin with. And remember, when making modifications, anything you gain in one area will be lost somewhere else. If you just want the bike to run right, I suggest leaving it stock, except for removing the air injection system, then give the carbs a good thorough cleaning. You can also adjust the pilot screws on both carbs. Both should be adjusted the same. Proper adjustment should be between 2 1/2-3 turns out.
There are many things that can cause a bike to not run right, from dirty carbs, to an air leak in the intake, to bad spark plugs or other ignition components. The Vulcan 750 runs great completely stock when everything is right.