What is a boost bottle for a Yamaha blaster?

Answer 1

A boost bottle is used to help an engine run a little better when its RPM's are under the useful range of the pipe. Carburetors will double dip - that is double jet the mixture coming from the carburetor due to the intake signals received by it (a suck and blow situation). It will push the mixture back past the jets and (try to) jet it again. This makes a condition which is too rich - hence the double jetting and the dip in torque. This usually occurs at an RPM level just before the power is coming on the pipe. This happens to the Blaster engine at about 5000 RPM. The boost bottle will capture and release its charge when the frequency of wave amplitude within the inlet pipe is within its working range. To tune out the dreaded (and well known) 5000 RPM torque dip the Blaster can be fit with a bottle volume of 250 CC - this includes the bottle itself and the connecting hose. When the bottle volume, tube length and tube diameter are properly designed it will work as intended.