yfz top speed

[dogmanjayx]

whats the best gearing 4 the yfz450? i dont wont to take 2 much away from the bottom, but would like good speed on top. maybe someone has change the gearin to see this already. i dont want to buy 10 sprockets, just to see the difference. i have a full exhaust fmf with powerbomb header with stock gearing 14-38 running about 80mph air box lid off jetted close enough broke in properly

[yfz450kid259]

well i was goin 80mph no lie next to my friend in his 2005 gt mustang in 5ht gear and not even pinned yet!!! but i also only weight 140 pponds.:blah:my all stock to nothing done to it just baffle out

[YFZ450Ridr]

Originally posted by yfz450kid259
well i was goin 80mph no lie next to my friend in his 2005 gt mustang in 5ht gear and not even pinned yet!!! but i also only weight 140 pponds.:blah:my all stock to nothing done to it just baffle out

i dont see that possible when 450s run like 77ish toped out and your saying your not pinned yet? no way.

[parkers30]

you have to remember that at 70 mph many cars and trucks are 5 or more mph off so he may indeed only be running 77-76

[YFZCHAMP]

depending on the temp, the altitude, jetting, mods, humidity, you can flat rip on a yfz. Mine , with 4.25 in intake kit, the punisher ignition, LRD pro exhaust, proper jetting, and 18in rear tires, can knock on 90 on flat ground with good traction, pinned.

[dober250R]

sorry but I have to get the bull**** call on the kid that said he was going 80 next to a mustang and not being pinned. Was the mustang pushing the quad? kinda hard to believe. get some proof, how bout a video?

[E-ATV-Racing]

Well I always think it is funny when some quotes a top speed that is faster than the bike can physicaly go. The top speed of a stock YFZ, even with a mouse at the controls, is 77.86 mph. This speed assumes that the bike is able to rev out to 10500 rpms in 5 gear. If the punshier allows the motor to rev higher, then higher speeds are possible.

It is only math, anyone want the formula? if not stop reading

PD--Primary drive ratio is 2.82
TG--5th gear ratio is 1.05
FD--Final drive ratio (14/38) is 2.71
RL--Rev limit 10500
TD--Tire diameter is 20 in
pi--pie 3.41459

Speed =(RL/(PD*TG*FD))*60/(5280/((pi()*TD)/12))

Speed =(10500/(2.82*1.05*2.71))*60/(5280/((PI()*20)/12))=
77.86 :)

Using this fomula you can plug in differnt tire sizes and gearing to see what it does to the top speed.

Remember the bike may not be able to pull the revs with out mods. :(

[YFZCHAMP]

Maybe he was going down hill, but without a Aftermarket CDI, I doubt it as well.

[YFZCHAMP]

The punisher Ignition revs to 12500, and electronically advances the timing (same as cam mods without the motor work), this allows you go like a bat out of hell, With my mods at woodburn drags, with slicks ( I race MX, but tried this with a friend who races pro dragbike) went 92.34 in the quarter 57degrees no wind. That was under drag strip conditions with special tires.
As for the exhaust and 4.25 intake, I got another 7HP (average) without sacrificing reliability. MY quad is not even close to stock, It has lots of mods. But a stocker is not breaking 80 unless he is going down hill with a tail wind.

[ml450r]

Your pics show an mx quad, If you have an mx quad geared to run 90 you've lost your mind. Now you could easily change your gear to a 16 tooth front and run 90 on asphalt with enough motor but.....WHY?

By the way your ignition doesn't do the cam mod for you. Ignition timing and valve timing are not the same.

[YFZCHAMP]

Yes, I know, I stated as much above, the aspalt thing was for grins. PUNISHER CDI, I said it does the same thing, not that it is the same things, IE; has much the same effect. NO, it does not work the same way, no need, if the effect can be reach effectively and still be reliable.

I have several championships on this quad, Holeshot all but three motos the entire year, And those were slop-mud mess.

The question was how much top speed can you get, MY answer is in no way concrete, I just illistrate it can be done, with a few mods, if someone cared to go all out , You could get over 100MPH out of one of these pups, but you have to try it, and then tinker until you get there. AS for me one weekend ou the pavement was enough, I will stay on the dirt, like it better, it has jumps.


YFZCHAMP
4stroke pro-am and open expert champ 2004

[motoxrider519]

pi isnt 3.414 its 3.14

[hardkoratvmxr]

we put a gps on a stock one with a uni airfilter and a 125 piound rider and he went 76-77 range

[future 450?]

yfz tops out at around 64

[playmaker3737]

m friggen warrior tops out at 63 with no pipe 80 degrees, 10 knot tails winds slightly downhill:eek2: :eek2:
and dont say bs bc u HAVENT RIDEN IT AT THOSE CONDITIONS

[mx426ex]

probably close to a gillion and 5

[Doober]

Originally posted by mx426ex
probably close to a gillion and 5

thats a pretty close estimate:rolleyes: lol

[YFZCHAMP]

Originally posted by future 450?
yfz tops out at around 64

That may be true, but only under certain conditions, if you change the variable, and the jetting to match, 64 is a meek number. I have a police freind who clocked his stock yfz and level ground, sea level, no wind, at 76mph, so if your getting 64, you should ask why....:cool:

Originally posted by future 450?
yfz tops out at around 64

:eek2:

[YFZCHAMP]

I like and subscribe to your saying, Life is to be lived not wasted:cool:

[mx426ex]

once again... yfz top speed is around a gillion and 5

[250x_kyle]

yfz top out at oubout 70-75 stock

[WORCSYFZ199]

I think the best gear for my type of racing (WORCS, high speed gran prix and some moto) is a 15-38 but only if you have a little motor work so it can pull the taller front sprocket.

[JRP]

id say 76-78. mine tops out at 78.

[raptor_02]

if u want top speed out of the YFZ stick with stock size tires, 15 tooth sprocket on the front, kn filter, pipe, jets, and last but not least the cam mod and you will be hammering. I'd say with that setup you could take a stock yfz by a true 10 quad lenghts or more depending on the distance.

[tye101]

man, the bull @#%^^#$%'s really came out in this post,, i have had a cop friend of mine clock mine at 84 mph, 89 degrees, 10 mph wind, i weigh 150, i am stock gearing ,, lol, the guy with fomula sounds good,, but not knowing what pie is,, i am saying he doesn't know his *** from his elbow

[korniev]

As soon as I changed to ITP 19' tires I noticed that I stopped running my bike on 1 gear at all. I have 38 sprocket on the rear. Just ordered 37. We'll see what happends.

[ACEwrench]

DirtWheels did an article on this subject a while back...

i believe they had 22 in rears on it with a gearing of 14/36 being the best... 15/38 was about the same

if i remember right they did this on a drylake bed and with GPS the YFZ got to around 87 mph, 450r around 88

[ACEwrench]

and hey isnt PI= 3.14 not 3.41

[korniev]

Originally posted by ACEwrench
DirtWheels did an article on this subject a while back...

i believe they had 22 in rears on it with a gearing of 14/36 being the best... 15/38 was about the same

if i remember right they did this on a drylake bed and with GPS the YFZ got to around 87 mph, 450r around 88

Well of course they did the same cause 14/36 does not differ from 15/38. As soon as you compare 15/36 and 14/38 then you see the effect
Probably me changing my rear from 37 to 36 would not really fill!

[ACEwrench]

Originally posted by korniev
Well of course they did the same cause 14/36 does not differ from 15/38. As soon as you compare 15/36 and 14/38 then you see the effect
Probably me changing my rear from 37 to 36 would not really fill!

yea, thanks....
i know 14/36 is about the same as 15/38.. i say about cuz 1 tooth on the counter shaft is worth almost 2.5 teeth on the back. im guessing that the test quads just would not pull 15t counter shaft spocket cuz of the size of the tires and gearing...so the MPH essentially were the same..