Dirtbike

clean the filter.

ya ill do that ill trey anything haha my bike is horrible when i try to whellie it like wont even get the front tire up unless i yank on it as hard as i can

what do you ride? and remove the spark arrestor if you can, should help some

Make sure the carb is properly jetted.
Make sure you have a decent gear ratio.
Mufflers or full pipes can be added depending on the amount you're willing to spend. If you don't have a ton of cash check out craigslist or sleezbay and consider picking up a used one.

what do you ride?

dude learn how to ride on the pipe, and really keep your speed up through corners and stuff, If you relaly learn how to "rip" ur bike, u can haul ass. My friend wins the Pro Enduro and Mx's on his Kx 100.....

Pipes and jetting. Also get those kevlar grips. I love mine

You could do a number of things,

mod your airbox so it gets more air, Higher Octane Fuel, muffler, different sprocket set up, and stickers will make it go faster.

as for wheelies you got to clutch it up bra!   the power of a dirtbike is within the clutch. Use this and you will suceed young master.

what those guys said, that'll get the job done, pipes is major. along with gearing, and jetting, ya just about everything will help.

Yeah basically all the same shit everyone else said. But what are you riding? I have a feeling its gonna be a CRF100 or something, in which case it's just a pussy bike.

sorry but the only noticible thing  you can do other than change gearing, which isnt even making your bike faster, its just changing power delivery -  is to get a motor kit and bore it out.

my 250 - 280 kit was extremely noticible as it now power wheelies in fifth gear and before it didnt.

its a yamaha 125 4 stroke its kinda old like 03 and would takeing the baffle out of the muffler do anything or just make it louder

just do your top end, cause you probably havent done that since you bought it. you will notice the compression

i would be baffled if you gained noticeable power from removing that

i did that with my old bike and it makes it a little more peppy but not much. think new pipe, air intake, gears, basicly what everyone else said

I know you said you want to keep it cheap but BBR has some sick mods for 125s like that you get them haulin with some real power

Do a top end before all of those things though. How easy is your kick start?

paint it a fast color.

it kicks pretty easy

gearing is everything.. changing the front and back sprockets can gain you pep or top speed, it may even gain you both depending on what is on it now

yes!

http://www.thumpertalk.com/forum/forumdisplay.php?f=37

Step 1) take care of air flow: 
                                            hack of as much of the top of the airbox as structurally possible, next take out
             the baffle on the pipe. (I'd get an aftermarket pipe for sure, but nothing fancy)

Step 2) re-jet:
                      Step one will make you bike leaner so unless it's already too rich it will need to be re-jetted
             if you've ever done it before its not hard but you need to know how a bike is suppose to behave
             and you should have some basic skill. You should find someone you know that has said traits.
              Jet kits are cheap under $50 in most cases.

Step 3) Gearing:
                           making the sprocket bigger will make it wheelie better but you will loose top end speed.
             A "race" chain is a chain without O-rings it wears faster and requires to be lubed more but is
             lighter which will reduce rotating mass and get you more HP to the ground

Step 4) Maintenance:
                                   keep your tires fresh with nice sharp corners on the knobbies, clean air filters
           (once you complete step 1 your filter takes in more air faster dirtying it more and faster) keep you
            chain tight to avoid sprocket and chain ware.

Imo "rev boxes" are a waste on such models ass the TTR they dont change any ignition timing all they to is give you a higher rpm allowance, which is usless on fourstrokes becuase you reach peak HP way below peak RPM. If yous has electric start you can always remove the battery and any other electric start componet possible to loose weight. (as long as it has a kick starter too)

As far as motor work goes anything other than a simple rebuilt is a waste of money, bore kits and such are a waste and will lower the likley hood of reseling the bike. (dads usually by these bikes for sons and if its a frankenstein they will assume it has been beaten)

I used to have this model of pipe on my old crf 150 its a great model really loud thought that was my only complaint, http://cgi.ebay.com/ebaymotors/New-FMF-Powercore-4-Exhaust-00-07-Yamaha-TTR-125-L_W0QQcmdZViewItemQQ_trkparmsZ65Q3a1Q7c66Q3a2Q7c39Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem3ef60e25a0QQitemZ270416094624QQptZMotorcyclesQ5fPartsQ5fAccessories

repacking your pipe can sometimes get you back 2-3 horsepower....and if you get a bigger back sprocket youll get more torque, a smaller back sprocket youll get more speed and its the opposite for the front...for a ttr 125 i would get a different pipe in general cuz theres not much you can do with a stock trailbike

a TTR from what I rember doesnt have a "packable" pipe it has a series of baffles like a car muffler.
and if it did you would never get a 2-3 hp gain/loss out of it becuase it probably only has around 10 hp to start with.

I have a crf250 with white brothers dual carbon pros' (claim/) and I'll be the first to tell you that putting a pipe on a race bike is a complete waste of money if you want more power. but on a "muffler" style bike (like the ttr) it is essential to tuning it up to all you can get out of it

I hate you.

Your granny shifting not double clutching like you should.

is the ttr 125 the 2 or 4 storke becuase mine is 4 stroke

does it have a speed governor? i took that off on my go kart and it felt like the scene from water boy when vicki fixes his tractor

haha maybe i read in a magazine that there is a block in the stock throttle that you can take out if you wanted