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Trying to perfect my race engine I found it almost impossible to get the jetting right. It seemed like there was a small air leak. I pressure tested the crankcase and there were no seal or base gasket leaks. My intake and reed valve were tested to be leak free. I messed with how the Dellorto carb mounts on the reed valve and finally got that perfect. But still the problem persisted. Then I took an investigative look at the Dellorto carb and found an air leak path designed into it! Taking the carb off and putting the slide in place and shining a light into the carb I could see light between the front of the slide and the carb. Air comes in over the slide from the air filter (and also from where the throttle cable connects to the top of the carb), goes past the front of the slide, and then gets into the air/fuel passageway through that small space between the slide and the carb. I can't believe they designed it that way. The design should be that the slide slightly scrapes the carb to seal and prevent any major leak. So now I have a Mikuni 18mm carb on order and until then I will put JBWeld on the slide and sandpaper it down till it just barely touches the carb. That should allow me to finish testing on a new pipe design.
I will probably have to let the machine shop lathe a new aluminum piece to replace the manifold piece of the Rock Solid reed valve to match the carb. Once I get the carb I can tell you all the inner diameter of its clamp so you'll know what size to tell Rock Solid to make the manifold on the reed valve you're ordering.
I will probably have to let the machine shop lathe a new aluminum piece to replace the manifold piece of the Rock Solid reed valve to match the carb. Once I get the carb I can tell you all the inner diameter of its clamp so you'll know what size to tell Rock Solid to make the manifold on the reed valve you're ordering.