Hey, ridden my trx250ex for about a year and I'm pretty bored of it so i decided to put some mods on it. Mainly I'm getting a Big Gun full exhaust system, also a K&N Air Filter.
1. What is the stock horsepower (at the wheels) of a 250ex?
2. What is it's top speed stock? (I've heard 52-54mph)
3. What horsepower increase can I expect from the upgrades?
4. With the new exhaust do I have to deal with the jets on a K&N Filter?
5. What are some other tweaks to enhance the ATV's performance (free)?
6. What are some other upgrades to buy?
7. Is removing a RevBox safe for your ATV? I don't know how to but I hate hitting the . limit on it..

That's the end to this rabble, but I'm inexperienced and could use some advice or info!

 

Nobody has an answer to any 1 of the questions??

 

I'm not sure what the hp numbers are on the 250ex but there is lettle you can do to it beside a pipe and jetting. The 250ex WILL NEED to be rejetted after adding a pipe and a K&N filter. You should get some airbox vents (rockymountainatv.com) and install those in the airbox lid. The 250ex doesn't like too much air, it leans out very easily.
I wouldn't change the rev box if I were you. It wouldn't have much of a performance gain for the money spent on the 250ex.
If you are really bored on the 250EX I would suggest you move up to either a 300ex or a 400ex.

 

Is rejetting difficult to do? If anyone can describe how to do it in detail, it would be nice.

 

You must remove the carburetor completely from the unit. Make sure you have a nice area to lay the carb out so you don't lose parts. Take off the top cap of the carb first to remove slide and main needle. flip the carb over then remove the float bowl.
The main jet is located in the float bowl chamber. You shoul be able to figure it out from there.

 

Actually no, ty for the help though, I really have no idea what the jets look like or what to do to them.

 

I suggest that you take it to your dealer if you need jetting done. Rule of thumb for you though. If you change exhaust going out you need to change air and fuel mixture going in!
I wouldn't expect large gains from that at all either. You may be throwing your money away. Stick that money in your new atv fund. Save up, trade in and upgrade to a 400EX (hands down).

 

Hmm. Ok ty for the advice, I'm a 5'2 - 100 lbs :-P 400ex would probably be a little too much, at least in the eyes of my parents. Pretty much mastered my 250ex other than jumping, have no acsess to good jumps.

 

Pipe it, install the airbox vents and k&n and then take it to your dealer or a reputable bike shop and have them rejet it.

 

Well then! Like Red400EXrod said...