top speed increase?

[jellybelly559]

what can i do to increase the top speed on my 85 250r? already pipe'd fmf fatty and powercore silencer.....i raced a trx450r that was jetted,intake,full exhaust,several other things that i dont remember and i had him from a dig and from a 1st gear roll and 2nd gear roll until i topped out in 6th gear......when i was maxed out in 6th gear he passed me and kept pulling i was really suprised because i thought it was stock at first.....so what can i do to increase my top speed with out a big bore or rebuilding the engine? had it rebuilt about 2 or 3 weeks ago

[KASEY]

a big bore will not increase speed. you will have to gear up,,

[jellybelly559]

sprockets? or go in the crank case?

[ironchop]

quit shifting too soon

[jellybelly559]

im shifting at the end of the power band waiting till the last milli second

[RubberSalt]

gearing can increase top speed but lower acceleration, come 6th gear, how hard did he pull away?

[TommyBoy1971]

I ran across some informaiton from another site I thought it was quite handy. this is based on a trx450r, but the idea still works for sprocket, tire ratio.
...... 12......... 13......... 14
36... 3.0000... 2.7692... 2.5714
37... 3.0833... 2.8461... 2.6428
38... 3.1666... 2.9230... 2.7142
39... 3.2500... 3.0000... 2.7857
40... 3.3333... 3.0769... 2.8571
41... 3.4166... 3.1538... 2.9285
42... 3.5000... 3.2307... 3.0000
Dropping a tooth in the front or going up one in the rear gives you more torque and less top end.
Going up a tooth in the front or down one in the rear gives you less torque and more top end.
All this is contingent on what size tires you are running
Here is a good formula
Divide driven by drive (Driven=axel sprocket Drive=engine sprocket)
Example. On a stock 07 the Drive is a 13t and the driven is a 38t so divide 38 by 13 and you get 2.92. This is your final drive ratio, with a higher ratio you get more torque and less top end and when the ratio is lower you get more top end with less bottom end. The stock trx ratio is about perfect IMO so use that as a starting point. When you change tire size in the rear you need to take gearing into consideration, because tires effect gearing ( the smaller the tire the more torque you get) here is an example If you are changing from the stock 20" tires to a 18" tire that is approximately a 10% decrease so you need to decrease your ratio by 10% to get the same torque range and not to loose your top end. so if you like you stock gearing than you would change your gearing from 2.92 to 2.62 or something close to that.

If you remember this formula then you don't need any charts to figure out what gearing to run

[whyzee]

holy crap, how much faster do you want to go ...?

[Xpress]

Carbs and pipes only improve acceleration and engine performance, which does not necessarily translate into a higher top speed- you might gain an extra mph or two with a good carb and a good pipe. That doesn't mean it's going to perform like a stock engine, chances are, you are going to notice a more snappier engine when you get on the gas, with a couple mph speed gain possibly, but otherwise, you're not looking at a faster bike in speed.

If you want higher topend speed, you need to re-gear, a lot of guys (cocky banshee owners) don't get that. With more power output from the engine means more power to turn a different set of gears. You can probably drop down a couple of teeth on the rear sprocket with a good carb and your pipe which will increase your top speed, but likely give you a stock feeling with acceleration.

Just my $0.02..

[RubberSalt]

Xpress is right on it, more acceleration with the mods, but it's only going to go so fast, that's when you re-gear.
NOW there is 1 change that can throw the whole game off, tires. There are a few tires that expand upwards of 40% at high speeds. I don't know all of them, but a few of the popular 1s are; Maxis 4 snow, pro wedge 2, and scat trak haulers. This changes your gear ratio at your top end, but keeps the same acceleration. These tires have given me a nice advantage on my yt175.

If your in the snow, sand, mud, dirt - the maxis an the pro wedge kick ass. The dirt just brakes them down faster and it's harder to stop - more skidding around lol.

[Xpress]

Another thing that hasn't really been touched on is if you run a set of lighter tires and rims, then you can re-gear as there is less mass to get rotating. Running a set of light rims and 18" tires would let you use an even smaller sprocket than what the "chart" would show you to use, as the lighter tires provide less work for the engine to spool up.

Granted, smaller tires aren't good for trails, or really anything other than sand and tracks..

[dcreel]

Another thing that hasn't really been touched on is if you run a set of lighter tires and rims, then you can re-gear as there is less mass to get rotating. Running a set of light rims and 18" tires would let you use an even smaller sprocket than what the "chart" would show you to use, as the lighter tires provide less work for the engine to spool up.

Granted, smaller tires aren't good for trails, or really anything other than sand and tracks..

Everything I have read and dealt with is that gearing has to do with overall diameter of your powered tires. Lowering the weight of your overall tire and wheel will just get you to the same top speed faster, with less wear on your trans, and will make your brakes work less. I've owned and geared alot of "monster" trucks, Running a 40" mud tire on an aluminum wheel or a steel wheel will still use the same gearing.

[ceaserthethird]

Love the chart !

[jellybelly559]

gearing can increase top speed but lower acceleration, come 6th gear, how hard did he pull away?

he pulled away pretty damn hard in all honesty.....i was topped out and he just passed me and kept going ima say after he passed me within a matter of 10 seconds he was like 3 car lengths in front of me

[jellybelly559]

holy crap, how much faster do you want to go ...?

fast enough to beat him......i beat the crap out of a yfz250 and kept up with a cr250 pretty easily but he really pissed me off after we raced we rode a couple ditch banks and kept kicking rocks at me purposely cause i was behind him and when we got to the end of the ditch bank he was like "oh well ima go home i did what i came out here to do,beat the 250r" so i got in front of him on the ditch bank and kept fish tailing so i kicked up alot of dirt so he finally stopped and waited till i was about a 1/2 mile in front of him till he started going hahahaha

[jellybelly559]

yea that was a d*** move of me but he really pissed me off

[pantera1975]

Put on nitrous

[jellybelly559]

^ i wish hahaha

[KASEY]

wow if one guy on a banshee beat you and you get that mad... please step away from the car,,, !!! i will tell you .. you don't have enough money to beat everyone that you come up against!!

[Xpress]

Yeah, somebody's always going to be faster than you...

[beets442]

If you have a two stroke this is a must read http://3cyl.com/mraxl/manuals/bell/performance-tuning-graham-bell.pdf

[deschlayer]

If you have a two stroke this is a must read http://3cyl.com/mraxl/manuals/bell/performance-tuning-graham-bell.pdf That link Is BadA55

[beets442]

And for those with an edgamucation, chew on some of this http://www.datafan.com/TunersHandbook/2-strokefiltered.html I know it hurts:)

[jellybelly559]

i know your not gonna win every race....and your not gonna win every fight,arguement,etc etc. but this guy seriously pissed me off and i just want to show him that a 26+ year old machine can still keep up if not beat a newer machine.......im not trying to have a drag bike but just the way he was acting got to me...they invited him out there just to race me and after he won just im goin home i did what i came for? like come on man your not the s*** he needs to be put down hard to relize hes not the best

[jellybelly559]

like to me this is more than winning a race if it makes sense? to me its a thing of showing them that a older machine that was only made for 2 years can still compete....there arent that many R's in my town just a few and all they really do is go to the dunes....ive seen a couple 350x's but thats about it....to me its a thing of keeping the R alive in my town and keep it shining

[brd812]

gear up 1 tooth in front and I would guess you could cut it in half at the top end. What do you have on it now?

[atc007]

Gear up one or two on front. test it and get used to getting thru the gears right with whatever gear you end up pulling.Old school trick,,if you're racing on a hard packed road,pavement or dirt. pump your tires waaay up,like 15 psi. Pull some wheelies to make sure you're not pulling to either side. Use your thumb nail to let air out of the side it's pulling From. You will Fly! Obviously if you're going riding all day,,you aren't gonna be hooking up real well. But for a quick sprint down the road. You'll get him with an R.

[jellybelly559]

Gear up one or two on front. test it and get used to getting thru the gears right with whatever gear you end up pulling.Old school trick,,if you're racing on a hard packed road,pavement or dirt. pump your tires waaay up,like 15 psi. Pull some wheelies to make sure you're not pulling to either side. Use your thumb nail to let air out of the side it's pulling From. You will Fly! Obviously if you're going riding all day,,you aren't gonna be hooking up real well. But for a quick sprint down the road. You'll get him with an R.

think ima try this....all i have is a fmf fatty gold series powercore 2 silencer pretty sure its been bored once or twice and thats it that i can think of....im thinking about reed spacers? any real gain?

[beets442]

Gotta watch out over inflation, I've had the tire expand off the rim, especially the front. You don't want to know what happens after that.

[Xpress]

^Especially with older tires, those aren't a pretty sight...

[kristofrogers]

Beets, that first paragraph IS EXACTLY how I felt about 2 strokes until I picked up my first Tecate xD

[jellybelly559]

i was thinking of just inflating them to the max not to 15psi.....i dont think there older tires haha

[brd812]

tell us your gearing.....

[jellybelly559]

stock *facepalm

[brd812]

you need to get to 14/36 to get in the game. we ran a 36 back almost all the time and adjusted between 12 to 15 on the front, 12 and 13 for mx and short track and 14 to 15 for tt and dirt/sand draging. w/ 20" tires, w/ 18" go up 1 tooth.

[jellybelly559]

im gonna go to tha shop tomorrow and price it out