is my friend full of crap???

[allaboutHP]

my friend just bought an 03' stock kfx400 and brags about it constantly. first he tells me that he raced a cavalier w/ a turbo and beat it for the first 1/4 mile, and then he said the car was going 83 mph on the road and he was right beside it. then he said he can smoke me easily, im pretty sure hes full of **** because he has the same thing as a z400 and i can barely beat my freinds piped z. what do u all think?? does 83 mph sound like BS????

[honda_rider_08]

yes he is full of sh**

and yes you will beat him with a 440ex

[montyjcm]

How do you just barely beat a z400 with your 440?:rolleyes:

[Billdog350]

With stock gearing the rev limiter kicks in somewhere around 67-70 mph. Unless its geared to the moon and has some decent Hp, I wouldn't expect more than 70.

[dpizz450]

Originally posted by montyjcm
How do you just barely beat a z400 with your 440?:rolleyes: '

i was jus wondering the same thing.......and no they will only reach up to about 70-73

[allaboutHP]

the kid that has the z400 has 22" tires and i have 20" tires and he also dropped a tooth on the rear sprocket and i have stock gearing. we drag about 1/4 mile and i beat him by about 2 quad lengths, same way when we switch quads. yea i was thinkin that he was full of it since the kid that sold it 2 him said he could only beat a stock 400ex by 2 quad lengths

[Billdog350]

According to this handy little calculator I found online: http://home.earthlink.net/~gellett/ltz400.htm

He should pull 77 mph IF he had enough power to pull that gearing. With just a pipe I doubt he has power to pull 77 with 22" tires.

[allaboutHP]

he doesnt have enough power in 5th gear unless he hits the rev limiter in 4th, and then 5th gear pulls slowly. but his low end power sucks and that is why im not going to gear my 400ex any higher. that calculater site is pretty interesting, but the rpm makes a huge difference in the top speed

[Billdog350]

Sounds like your friend is gearing for pure top end...so you guys must have enough space to get up to speed...If that's what your drag race is about then figure your torque/hp curve and then find the optimal gearing for top speed. Otherwise set a given distance and do a true drag race from point a to b and see who gets there faster. Unless his power is way up there, he'll only be able to do one or the other.

[PEPwalshZ440]

full of crap, iun think even my R could do that.

[allaboutHP]

well i always try to get my friends to set up a 500ft drag race but they always think that is stupid. they like goin 1/4 mile, so even if someone gets the holeshot they can still get beat pretty easily.im thinkin my 440 hits low 70s with stock gearing, what do u guys think? oh yeah i raced the kfx400 today and i beat him by about 3 quad lengths in a 100 yard drag. he still thinks he can beat me though?????? but i like his quad alot and am thinkin about findin a used 03' z of kfx, i like that reverse deal too. what are some oppinions about this idea??? is it worth it???

[allaboutHP]

today i went up with a group of friends where we drag race, well there was a 400ex, 3 z400s, a kfx, my 440, and a 450r. 1st i raced the 400ex which is stock besides a smaller rear sprocket.and i smoked him out of the hole and for the fist 300 ft or more. than he passed me?????? the same result with a z400, and again with the kfx. then i beat the 450r until i hit 4th gear and he passed me. what should i do to get more top end with out losing all the bottom and mid range power that i have???
i was thinkin the hotcam stage 2, what do u all think?

[Billdog350]

The 400ex doesn't rev as high as a Z400 or TRX450....even with a REV box you're still just about even with the rev's of a stock z400. The higher redline allows you to "overrev" your motor for better accelleration in the powerband, as well as a little extra up top for high end speed. Even with your big bore kit you're not getting any more revs (unless you have a rev box, and even then it's not much more) so I would say unless you're totally reworking your motor you're probably better off starting with a more torquey and high hp high rev (ATV) motor like the z400 or YFZ. IF you guys are all about top end speed, then you can try to increase your front sprocket a tooth or drop the rear one or two to find your "sweet spot" where you're topping out at your peak hp. But be aware you WILL lose low end if you gear for speed...no two ways around it.

[allaboutHP]

well i ordered new sprockets with a 15 front and a 36 rear, so i should get more top end, but im gonna be lookin for a good deal on a yfz or try and get a trade in. i rode the 450r and i didnt like it, the front end at high speed was too twitchy, the z felt good but seemed like it was too high. im not sure but i think the yfz sits lower than the 450r and the z.

[Billdog350]

Ya might want to check but I thought the 400ex was 15 front and 39 rear for stock gearing...or possibly even 38 rear stock. I think you'd want to see a 16 up front for optimal top end (assuming you have the HP to pull it). Also, remember that 1 tooth up front is worth 3 in the back.