Check your vacuum lines

[Jacine]

With this heat, the rubber in the lines softens and can slip off the fittings. If your bike just has plastic non barbed t connectors, think about replacing them with brass barbed connectors. Available at the local hardware and even walmart. It will probably improve the vacuum.

[90GTVert]

The Chinese use fairly soft, thin wall vacuum hose which is of poor quality. If you take the vacuum T down to your local auto parts store and get new hose that fits snug you'll save a lot of potential problems. You'll also notice that the hose they sell has a much heavier wall thickness so it doesn't get loose from heat like the Chinese stuff does. The same is true of the fuel lines, which are prone to kinking because of the thin walls. The other place that leaks are common is the intake manifold, which tends to crack over time from getting brittle. The Chinese aren't great when it comes to rubber and plastic compounds. Stan

jacine said:

With this heat, the rubber in the lines softens and can slip off the fittings. If your bike just has plastic non barbed t connectors, think about replacing them with brass barbed connectors. Available at the local hardware and even walmart. It will probably improve the vacuum.