Posted by David K. on June 25, 2000 at 05:37:25:
So much has been said about faulty petcocks! It seems that riders are having trouble with fuel delivery, because the petcock automatically closes, when it should not (while running). Some riders are drilling a hole in the petcock to keep from proper closure. This is bad because then it will not shut off when parked. Others wish to purchase an old fashion manual on/off petcock, which is not necessary, because even with a defective petcock can be made manual by placing it in prime to drive and in either other position when parked. This would be the same as replacing with a manual one. No one has the problem of it not shutting off, only staying open! Of course a new one that worked, as it was met would be nice, if the purchase price was less. Now to add another reason for the engine to act starved, I will tell you what my problem was. I had the same bad petcock symptoms, but a different cause. The constant velocity type carburetor opens the needle by vacuum and not by throttle cable as on simpler carbs. The throttle cable only controls an air butterfly and the resulting venturi vacuum lifts the slide and needle. The slide and needle were sticky and required some carburetor spray cleaner sprayed into the air filter inlet, while the engine was running and the throttle opened wide, shut and wide at the same time. This cleared the gum or what ever corrosion that caused the sticking.