I was told that changing to a K&N filter and changing my sprockets would give me some extra power for a reasonable price. does that sound right?

 

Tell us more about your bike. What do you consider to be "extra power?" Aftermarket air filters will help your air flow on the intake end, but if you don't change the output end, you haven't really accomplished anything other than spending money. Think about it; an engine is basically air, fuel, and spark in the proper respective doses. It's like rejetting a carburetor (remember those?) but not increasing the air flow toequalize the increase in fuel flow. The engine will run rich and foul plugs and run like crap. Just because you let the intake breathe better with a K&N doesn't mean you've accomplished your goal of "more power." It's the whole air/fuel/spark chain that must be considered.
As for the sprocket swap, it's a compromise between top end and bottom end. If you increase the # of teeth on yourrear sprocket, you'll get more bite off the line because you'll have more relative horsepower per turn of your tire. If youdecrease your teeth on the rear, you'll get more top speed at the expense of bite off the line.
Most manufacturers pretty well optimize the ratios and sprocket setups for respective bikes, based on horsepower, size, geometry, and what the typical rider would do on that particular bike. Do you actually "gain power?" Hmmm. I'm not convinced you do until you actually address topic #1. There is a reason Top Fuel guys don't run 250's. There's no substitute for displacement (andthe air/fuel/sparkequation.)

 

um you will most likely loose a hp or 2 on small engine, you will gain a small amount though on bigger engines. it happens all the time.

 

I completely agree with Jeff's post. Once you start messing with either-intake, fuel, or exhaust, You MUST compensate the other two also. I see many posts of people who screwed up their bikes by changing only the exhaust, or only the intake. For the average 250R owner, this type of mod IS MONETARILY NOT WORTH IT!!!

On the sprocket, I just changed out my original 14t front sprocket with a 15t. By going up just one tooth in the front, my 250R has gained much better range and usability per gear, but is slightly more sluggish down low. You could buy a higher count rear sprocket for more "snappiness", but your top speed will be dramatically reduced. Not to mention that you will be shifting through all your gears very quickly. The bike would also be completely worthless on the highway with reduced gearing.

That's just my 2 cents.

 

BTW,

This topic belongs in the 250R section. The DIY is for people to post their projects.

 

Well, i just recently purchased on 05 636 which came with what I believe is just a slip on muzzy pipe. Other than that the mechanical components of the bike are stock. I have heard several people throw the term K&N filter and sprockets around when they talk about more power. Just curious what i would accomplish by changing them. I might be many things but a mechanic i'm not. lol.Thx for all your input.

 

K&N didn't do much for me until I did the jetkit and exhaust. For your bike that would be a powercommander and exhaust. Sprocket change mechanically alters the gearing on the bike. Usually 1 less tooth in the front, 2 more on the back for your bike so that it will have more low end grunt.

 

For the amount of money, sprockets will give you the most value IMO.

 

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