You can modify your 49cc scooter in a number of ways to increase its power and performance. These modifications include alterations to the scooter's continuously variating transmission (CVT) and its air intake system as well as system upgrades such as a new exhaust system. Adding holes to the outside of your intake case will increase the air entering your engine as it burns gas. Modifying the CVT will enable you to either speed up acceleration or increase your top speed. Swapping out your old muffler will aid in the expulsion of exhaust which can choke your engine as it burns gas. Modifying your scooter in these ways can increase your 49cc scooter's top speed up to 10 mph.
Unscrew the fastening bolts of the intake case. For most 49cc scooters, there are two or three of these bolts at opposite sides of the case (top and bottom) that connect it to the aesthetic wheel guard paneling at the back of the scooter and to the CVT case. The bolts should be removed with a socket wrench.
Remove the air intake case once the bolts are removed. You may need to jimmy or wiggle the case slightly to disengage it from the air intake on the engine. Once disengaged, simply pull the case out toward the back of the scooter.
Add holes to the outside of plastic air intake case with either a drill or an awl. The holes do not need to be of a specific size, shape, number or position, but they should be placed only on the side of the intake case facing out and to the left of the scooter. You can drill or poke the holes while the intake case is still attached to the scooter, but it is safer to do so when the case is removed.
Take the intake case off as described in the section above. This is necessary to fully access the bolts holding the cover of the CVT case in place.
Release the kickstart from the side of the CVT case by pulling the pin at the base of the kickstart. You may need to loosen the pin head with a socket wrench before pulling it.
Separate the CVT case cover from the case base by removing the bolts fastening the cover to the base. There will be a different amount of bolts fastening the cover depending upon the make, model and year of 49cc scooter you are working on. The number of bolts will range from four to eight. They should be removed with your socket wrench.
Switch the two pulley wheels with new wheels. Smaller diameter pulley wheels will give your scooter more immediate pick-up and greater ability to climb hills. Larger diameter pulley wheels will let your scooter travel at faster speeds. The wheels are connected to the workings of the CVT by bolts threaded through a center hole. Remove this bolt with an air-powered impact wrench.
Detach the existing muffler on your 49cc scooter. The muffler will be attached to the exhaust system by either a series of bolts or by a locking clip mechanism. If attached with bolts, you will likely need a socket wrench and a socket extender to adequately reach and unscrew the bolts. If attached with a locking clip mechanism, you will need to cut the lock with strong wire cutters or bolt cutters. If your muffler is attached with bolts, you will need to install a new muffler that attaches with bolts. If it is attached with a locking clip, you will need to install a new muffler that attaches with a locking clip.
Slip the connection tube of your new muffler over the exposed exhaust pipe on your scooter.
Attach and secure the new muffler with either the bolts or locking clip provided with the new muffler.
