Front and rear sprocket setup for 04 400ex?

[ThreeDollaBills]

I'm not too clear on sprockets. Can anybody explain to me how to change the teeth so I gain more acc. instead of more top end. I think you have to decrease the amount of teeth off the front, but what about the back?

[jrafter]

i think mine came with a 14 front 39 back

and now its 14 and 38 back and it fills great

[ncsmash]

You cant just change the teeth you have to buy a new sprocket they are relativey cheap. If you want more acceleration go down 1 tooth in the front and you will feel a big difference and if you want to change the rear you actually go bigger in the rear. Its an inverse relationship between the two smaller in the front and bigger in the rear give you acceleration and bigger in the front and smaller in the rear give you top speed. I think the stock gearing for a 2004 400ex is 14/38. Hope this helps.

[Honda4lyphe]

Originally posted by ncsmash
You cant just change the teeth you have to buy a new sprocket they are relativey cheap. If you want more acceleration go down 1 tooth in the front and you will feel a big difference and if you want to change the rear you actually go bigger in the rear. Its an inverse relationship between the two smaller in the front and bigger in the rear give you acceleration and bigger in the front and smaller in the rear give you top speed. I think the stock gearing for a 2004 400ex is 14/38. Hope this helps.

15/38

[ThreeDollaBills]

How much top end speed do you think I would lose if I went with a 13/40 setup?

[tanner 222]

probably a lot. if i were you id only drop a tooth in the front first and see how it feels. if you want more maybe only go one bigger in the back but if you really dont like it then go 2 but i think youll like it with just 1 lower in the front. thats what i did to mine when i raced mx and i loved it. when you think of gearing its just like a bicycle. when you shift down in the front you go slower and when you shift up you go faster. in the back if you shift down you go faster if you shift up you go slower.

[ncsmash]

I think you would lose quite a bit i run a 15/36 right now but i have run a 14/38 and loved the tha bottom end power but when i was in 5th i was looking for another gear i can tell a huge difference between 1 tooth differnce up front. And yea the stock gearing is 15/38 i was thinkin of the 99's they have 14/38 thanks for correcting that honda4lyphe.:)

[tanner 222]

on my '07 400 i had it had a 14/38 gearing i know for sure cuz i changed both sprockets about a month after i got it and checked to see what they were cuz i wanted 1 lower in the front and the same in the back.

[oleboy87]

if stock is 14/38 i wouls run a 14/39 have an 02 and i tryed going down in the front but it was too much so i went up one in the back and its a great set up for me... you should try that first then if thats not enough then put your stock 38 back on then go down one in the front...

[russellsroost31]

my 08 came with 14/39
i ran 13/39 for indoor and faircross
i thinkin 13/38 wuld b perfect for outdoor

[Drfat400ex]

Stock 99-04 is 15/38 and stock for 05+ is 14/39. There's a gearing calculator in the sticky section that tells you what your top speed should be with tire size and sprocket sizes, change the RPM to 9100 though. It's not working for me but I think it's just because of my computer's virus protection or something.

[jgar]

I have a 02 with 14-38 sprockets. Low end is great but Iam always looking for 6th gear on the trails. 1 tooth in the front is = to 3 teeth in the rear.

[CJM]

Correct sprocket size is:
99-04 15/38
05+ 14/39

That being said, no one will be the same setup b/c of tire size, how and where you ride and what you have done to the quad.

I run 15/36 on my 00 and Im quite happy. Before when it was mostly stock I ran 15/38 and then 15/37. The mods I did, the more power I made the more torque I had and found top speed to be lacking. I still often reach for a 6th gear b/c I could use more topend-but it would hamper bottom end too much if I were to change it to anything else but what I got now.

Remember:
-Going up or down 1 tooth in the front is equal to 3 in the back.
-Front sprocket:
-Go up in size=speed
-Down in size=torque

-Rear sprocket
-Go up=torque
-Go down=speed