[SLESTAK75]

Some choose to replace the stock intake with a 32mm intake. This can actually reduce performance on a stock 150cc. The same can be said for a larger carburetor. If you choose to go for a larger bore then you could benefit from larger carb and intake, but we are talking basic mods here. We will have another thread on advanced mods. There is performance to be had from the stock intake. These are rarely if ever matched to the port on the head. The stock intake can easily be opened up to match the intake port on the head.To do this you will need a dremel or drill with appropriately sized stones to shape the metal. Remove the intake and spacer. Now replace the spacer and feel the underside of it to compare it to the size of the intake opening. Start removing material from the spacer until it matches the intake port. Now use the spacer to match the size of the intake opening. Once the intake opening is matched to the spacer then use your eyes and fingers to judge where material inside the intake has to be removed to give the smoothest and least restrictive path of travel from the carb side to the head side. DO NOT increase the size of the carburetor side and DO NOT smooth out the inside of the intake. It needs to be rough. I used spherical stones designed to fit in a drill to do mine. It took a couple of hours for the whole procedure but alot can be gained from this as these intakes are often extremely mismatched. Depending on what sort of flange you have on your exhaust you could do the same to it. It is recommended however, that the exhaust flange be" slightly" smaller than the exhaust port for best performance. Again, this opens even further the intake and exhaust and must again be accompanied by adjusting the main jet size in the carb.