There are certain tips to increase top speed .
1.Increase u bike tyre air pressure to say a 38 to 40 psi instead of original 32and get 30 psi in front instead of original 25.will do wonders but has its on side effects....
2.Get a higher octane petrol. get a 91 or 93 octane .it will definitely boost u r bikes top end performance........
3.take u r air filter out .replace replace it or . trial run without one .no air filter riding is not advised but doing it one or more time will not affect ur engine .Get a good set of free flow exhaust .will deffinetly improve the highend performance.
4.Give u r valve with more opening .will definetly reduce power and efficency at low speed but can improve high end perfomance because it improves volumetric efficency.
5.Get a better set of spark plug(iridium if u can afford) . and make sure u r ignition timing is advancing with speed .I think karizma is having 2 sets of ignition timing.one for low speed and other for higher engine speed. but not sure.If the timing is not advanced according to speed . it will reduce top end power.Check the control switch .Not sure where it is .Bajajs having it in there carburetor
6.And finallly the important thing since top speed is a factor which is closer of aerodynamic efficency rather than power when speed is increasing.Get a lower set of handle bar.crouch down entirely onto the front fairing .while doing higher speed.use only Tight jackets. or not use them .Bcoz loose jackes can cause a large drag.get a tight t shirt and Try.

Hi there.



There can be many factors man for variable top speed.
Even the minutest things like how you warmed up the bike in the morning also affects bike's performance that day.
Wind speed and direction can also be a factor.
Somebody very experienced even told that change in weather, also results in change is performance of the bike. (Availability of oxygen in air).

Firstly I think a stock karizma should atleast show a top speed of 125-130 single and crouching. This is just my thought.