My bent beam motorcycle was replaced by Jingbin carburetor, and the exhaust pipe of the middle and high speed throttle caught fire. How to adjust the mixing ratio of carburetor?

The throttle flap is the reason for the rich mixture. At medium and high speed, the throttle is suddenly turned back, the throttle is suddenly closed, and the air intake is reduced. However, due to its heavy weight, gasoline will continue to push into the combustion chamber, causing the mixture to be too rich. If other stages are normal and the fuel consumption is not high, it is normal. You can also check whether the air filter is blocked, whether the carburetor mixing ratio is too high, and whether the oil level is too high.