Quote:
Originally Posted by Texas Pete
You won’t increase horsepower by rejetting the carb. Your top end speed is reduced by the things you are hanging off your bike, panniers, bags, windscreens, tall and wide riders etc.
If you want to increase horsepower you need to put more fuel and more air into a given volume of engine. Fuel is easy to increase, air is more difficult to get in. Think super charger, turbo charger, nitrous oxide, etc. to get significant air increase to get a noticeable horsepower increase when fuel is increased. Or an easier way install a larger cylinder and piston to increase volume inside the engine at normal barometric pressures. Or the easiest way, buy a bike with a bigger engine already in it.
What you can do is play with shifting the torque band left and right across the existing horsepower band by retarding or advancing the timing—what you gain on one side you lose on the other side. You’ve already played with the gearing. In generalization a tooth change in the front sprocket is equal to three teeth change on the rear sprocket. I don’t have an M but having an X I was impressed you got a 16 on your front. Our X’s can go up one tooth on the front sprocket and that’s it with or without some grinding required to get clearance. I got a 40 tooth rear and will leave my front factory 13 teeth. If you notice going down 49 rear to 40 is a 9 tooth change. Going up 13 front to 16 from is a 3 tooth change and multiply by 3 and you get 9. Same effective net.
If your throttle response is bogging, or stuttering or the bike is popping on deacceleration you can clean those up with rejetting your carburetor. With the X it’s usually running lean out of the box I bumped my jets from #120 main to #125 main, #40 idle to #42 idle; and 1mm needle shim. In general you want it to run stoic to a little rich. Rejetting or buying another carburetor is not going to make you faster in your top end or give you more horsepower.
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Indeed it seems to be running lean. I have to choke it for a minute even during warm days. Then it gets a bit gutless from 75-100% throttle.
As for tall and wide riders, I’ve tried washing myself on cold and drying myself on hot, but it doesn’t work.