rejetting an engine?

[minitruckguy]

How hard is it?

What exactly are you doing?

Could a complete noob do it?

[Gimpdiggity]

Q-How hard is it?
A-Not hard physically. It's the tuning that's the hard part. 95% of jetting a bike is going to be absolute cake. The last 5% will cause you to want to gouge your eyes out with the nearest screw driver.

Q-What exactly are you doing?
A-Replacing needles, jets, and various other things inside the carbs.

Q-Could a complete noob do it?
A-I would suggest that you not try it if you have no idea how to do it. I'm a FAIRLY competent mechanic when it comes to engines, but jetting the thing was really...and I mean REALLY...a pain in the ass. It's a lot of trial and error. You have to rip the carbs apart, put in a needle and a jet, put the things back together, go for a test ride. Then you have to do that again with different sizes for the jets and different positions for the needle clips. You basically do this a few times until you feel the bike is starting to LOSE performance. Then you work your way back between the "best" two settings until you find the one best setup. All of this can take HOURS to accomplish. I've probably put 40 hours or so into testing and tuning my 250 with the jet kit...and it's still not 100% where I want it. It's 99% where I want it, but I'm still just a TAD lean at idle.

Now, all of this can be easier (i.e. no test rides) if you have access to one of those whip ass dynos like the ones that FactoryPro uses.

Speaking of FactoryPro...if you DO decide to try this on your own, go with a FactoryPro kit. Great kits, great sales, and GREAT service after the fact.

[minitruckguy]

Thank you for the help.

I have heard that it is not a necessity to rejet your engine on a 2008 ninja 250r like it is all other bikes when getting an exhaust/intake (full exhaust havn't decided between yoshi, fmf and area p but i know that I am going to go k&n for the intake) is this true?

[Gimpdiggity]

Originally Posted by minitruckguy

Thank you for the help.

I have heard that it is not a necessity to rejet your engine on a 2008 ninja 250r like it is all other bikes when getting an exhaust/intake (full exhaust havn't decided between yoshi, fmf and area p but i know that I am going to go k&n for the intake) is this true?

I would say it's not true...at all.

If you do intake and exhaust on a carb'd bike, then you will need to rejet. You'll be running way too lean through the entire range if you just throw some pod filters and a new exhaust on it. I very seriously doubt that Kawasaki has the bike jetted so rich from the factory that you wouldn't need to rejet after doing those mods. As a matter of fact, most bikes from the factory are running a bit lean on the low end to begin with...so doing those mods will make it even leaner. Would it be dangerously lean? Possibly. You might run the risk of damaging the engine.

What you really need to ask yourself though is if the money spent doing all of this is going to be worth it for the 250. I have done it all to my 250...and although I'm happy with the results, I would NOT do it again. It's simply too much money for too little performance. When it's all said and done, you'll have what, $3500 wrapped up in your brand new 250 and then another $600 or so in filters and exhausts and stuff. That $4100 would've gone a long way towards buying a couple year old 600 or a year old 500. Both of which are still going to be boat loads faster than the 250 will be. The only reason I did it to my bike was because I knew I wasn't going to be getting a bigger bike anytime soon and I also got GREAT deals on all of the parts.

Money spent on a 250 is better spent in the suspension and tires...all my engine work has yielded a slightly quicker and slightly faster 250...at the expense of being a MUCH louder 250. The suspension work, on the other hand, has been a godsend. It handles like a dream now, and feels much more planted to the road.

[minitruckguy]

Originally Posted by Gimpdiggity

What you really need to ask yourself though is if the money spent doing all of this is going to be worth it for the 250. I have done it all to my 250...and although I'm happy with the results, I would NOT do it again. It's simply too much money for too little performance. When it's all said and done, you'll have what, $3500 wrapped up in your brand new 250 and then another $600 or so in filters and exhausts and stuff. That $4100 would've gone a long way towards buying a couple year old 600 or a year old 500. Both of which are still going to be boat loads faster than the 250 will be. The only reason I did it to my bike was because I knew I wasn't going to be getting a bigger bike anytime soon and I also got GREAT deals on all of the parts.

Money spent on a 250 is better spent in the suspension and tires...all my engine work has yielded a slightly quicker and slightly faster 250...at the expense of being a MUCH louder 250. The suspension work, on the other hand, has been a godsend. It handles like a dream now, and feels much more planted to the road.

I am debating on the intake but i deffinetly want the exhaust because I want that beautiful sound, this is a beginner bike so i will probably hold on to it for a year or two.

I've heard that the suspension on the ninja 250 has changed alot for the '08 model and is now alot stiffer instead of the "springy" feel of the older models... if so i wouldnt really be worried about suspension.