YZ450F Top Speed Test (Tallest Gearing You Can Buy) 

I'm going to share a formula that is pretty accurate. It's not dead on but pretty close. For a dual sport or dirt bike it takes about 20 rear wheel horsepower to reach 80 mph. For each additional horsepower you can expect an additional 1 mile per hour. In other words a 50 horsepower mx 450 should theoretically be able to hit 110 mph on pavement or extreme hardpack. You can gear a bike as tall as you want but you need the horsepower to overcome the wind resistance.

My modified 88 YZ 490 would go 110mph off road just by dropping 2 teeth on the rear sprocket! It still had all the power you could possibly use through all 5 gears! It would still hole shot Johnny Greeves last pro race bike, ( 87 RM 250 ) every time! A good friend bought Johnny's race bike and he was damn near as fast as Johnny! His name is Rick Blaser, he eventually raced pro mountain bike.

6 gear wide ratio thats what u need

Need to go 14/46 or 48. You need to get the engine in the best part of the torque/horsepower band up near but not at the limit of RPM. Most dirt bikes make peak power at 9-10k RPM.

Damn this is a badass video. I like the drone view. Cheers from Cali 🤘

Dude that looked sick💯

Is the YZ geared that short compared to the WR? I went +1 on the front of my 2022 WR450F and it runs out of power before hitting the limiter.

Wasn’t on radar or anything but I’ve got an old 2008 KTM 530 XCRW that’s in good shape but not built or anything beyond a pipe, and it’ll do 155ish on a gravel road, which I will say is an experience. I owned a Gixxer 750 before, and also own an FTR1200 now, and nothing feels as fast or scary as a wound out dirtbike floating all over the the road, wind trying to rip you off the back, shaking so violently you can hardly see straight. The bike feels like it’s burning up on re-entry at that speed on gravel vs a street bike you’re tucked in behind the fairing and doing 275, smooth as glass

Watched a desert race in WA held on and around Lake Lefroy some years ago. Competitors were consistently hitting over 160 kilometres per hour on two stroke and early Yamaha 450 four stroke MX/enduro setups. From the look of some of the very scuffed up bikes and riders entering the mid race fuel stop it looked like a few of them had stepped off their bikes at very high speed on the salt during the race.

Nice one man!

My old xr650r did 140mph! Yes thats mph on the beach with the smallest available supermoto rear sprocket on the enduro wheels the trial tech digital speedo was struggling to keep up 😂

Really cool video! Question, how are you able to add timestamps/chapters on your vids? I've tried but they don't show up.

May also help to play with rear tire size.

Hell I’ve gotten my 2023 WR250F fully uncorked it’s still got stalk gearing 13 51 and the stalk exaust up to 147 km on the highway I think the speedo is wrong off by 7 km on my Wr but anyways I pick up a 48 tooth rear instead of 51 I ride more bush trails lower speeds 60 km fastest trail we have around here and doing 60km in the trail is not advised if you don’t know how to ride funn as hell that fast flowing trails

What JT rear sprocket type does this YZF have? I can find a 38 tooth for the rear that fits a 2015 450. Its labelled as Honda Tornado 250 but it fits 15-19 450's You can also get 39 tooth rears for a 2004 KX250 if you get KLX300 sprockets. Exact same bolt pattern :) Edit: there are also 18 tooth fronts for this bike. You still got +1room for front and -2tooth rear if the cases dont prevent a 18T 😁 (Double edit: seems 15 is the max)

That was cool 💪

Waow nice broooo !!

Back in tha day... I had a TT500 and put tall sprockets on it... I don't remember what size but it would do better than 100mph. Crazy scary with dirt tires on pavement.

I used to do this back in the day to try and coax a few more mph out of my DT 50 MX. Trouble was, it didn't have enough power to pull the higher gearing 😂😂

CT18 is the best thing to clean dirtbikes. Foam on, let it sit, wash it off.

The ultimate gearing for top speed is when you can just manage to redline it in top gear.

you need to get it onto a straight road because my 06 tm300 does that stock and 450s usually can keep up no problem

my mate still has a supermoto 1986 cr500 33 /17 sprockets we had that clocked at 140 mph

Do a quick video on pavement and youll go way faster, my stock 2019 kx450 hits 158kmh pinned gps verified 50tooth rear

Are you racing the Brookton Pony Express 2024?

15/44 You are going to fly🤫

My beta 300 does 150kmh on stock gearing. My buddies old ktm 450 exc would pull 190kmh. The thing would try and head shake like no other.

Just randomly geared based on what fit? Seems like guesswork as to getting the most out of the bike.

A 6th gear would help so much. But not really what that trans is for. My KTM 500 has 6th so I've hit as high as 178kms before I had to back off.

ive had my stock rmx450 up to 155kmph

14/48 i think is the best gearing for any 4t

In 1972 I went 93 MPH in the quarter mile from a standing start on a BSA B50 MX....

That ground is very spongy, put it on pavement with Super Moto tires and add 50km/h

If you were on hard ground or tarmac instead of soft lake you could easy add at least another 10 or 15 kmh

I have a 2018 kx450 and I was in 5th 3/4 pinned and I went 94.8 miles per hour

ive hit 148kmh on my 2021 wr250f, 6th def helps

In local-sponsored desert racing in Utah and California, the big 450cc bikes would come FLYING by me on the "lake beds" with my stock gearing. Enough of that!, LOL. I geared up my KTM 300 EXC to the MOON! Until it could not rev out because of the tall gearing - and backed it off one tooth on the rear. Those local-yokel 450s never passed my ass again !!! Pleasing feeling dropping down to 75 to 80 mph and downshifting into fourth to power through some sand stretches.

My 16 450fx went 138kph with stock gearing down a grass paddock.

Sicko

Just change to a road tyre on the back and will go much faster.

and to think they sit on 160-185kph on the Finke race for almost 2 hours straight one way in deep sand

Wow, my 2016 450fe will do 140kph with a 12 and 52 rear!

My ktm 625 smc would run 112 mph on the dirt.

15/44 is good for WR/YZ450, 😉

you need a slick tire and trying top speed on street!!, and use a little bit of a nitro fuel...

That’s unlawful what you did says people who don’t know how to have fun. I hate that everything in life is so restricted yet the people who restrict us tend to turn out weirdos and pedos or abuse power themselves. Ironic 😂

Yeww first here 🏍️

My CRF250M has 15 front and 39 rear and pulls 145 kph on Tarmac so your 450 needs looking at bud 😂😂😁😁🤘🤘🤘

if you did this with a WR450F you could probably go 110 mph

u have to b able to go faster, 09 klx250s 107mph

04:35 - Ranger Karen lol!

Get a ktm 500 would off dome that easy

I can do 115 mph on my 2012 wr450... you doing 96mph doesn't seem that impressive

It will do 150 with std gearing.

Lots of numbskulls in the comments who swear a smaller rear sprocket is all it takes to overcome unlimited wind resistance and the laws of physics , including a gentleman who swears his xr650 can nearly equal a 1992 CBR600F2 in top speed (145 mph) . All it took was a magic sprocket !

125 2 stroke is faster

yyyyyyyy

95 mph ?? thats slow as heck

location robbed a lot of speed

My 83 XT550 is faster than this 450. Hmm.

Hi i'm from Indonesian, spirit bro