need help on bottom end! Please!

[1dirty400ex]

hey guys. im new on here, but am needing some feedback from yall.

i have a 2006 400ex with a hmf slip on, dynojet kit, and maxxis razr back tires. thats is sadly :(
i am lookin to make my bottom end more powerful, cause i ride a lot of trails.

Im Wanting to drop a tooth of my front sprocket, but im not sure of the stock sprocket size. I need somebody to help me find the best parts for the best performance and best price. Any help with that would be great.

Also thinkin about a Curtis Sparks +6 timing key. Would i need anything else with that? and im slightly mechanical, would i be able to figure that out and put it on myself? not lookin to pay out the butt to have it put on.

And any other things i could do to increase my bottom end, and loose not much top end( which i know i have to loose top end to gain bottom end) would be great info. Not wanting to tear into the engine and spend a lot of money

Thanks, Kyle

[bigbad400]

i have a sparks key ill sell ya with the puller and im sure anybody can do this if they can read. there is a writeup in the sticky it explains it all. full pics and everything. any local dealership should be able to get you a sprocket from a parts unlimited catalog cheaper than u can buy one and have it shipped to you. other options are get a stg 1 or 2 cam and you only have to get into the rocker cover. no big deal at all. there like 140 new. plus a gasket 15. or you could prolly get a 450r carb for that price too. or a little more. you could also get a monster coil they dont give much but throttle response but its 40 bucks too i think.

[bullett]

The stock sprocket size for the 06 is a 14 tooth front and a 39 tooth rear.

what is stock on your 400ex mine is 15/38 if yours is 15 keep it change the back one cuz it will save your chain in the long run. go to ebay you can get a stage 1 hot cam for $124. SHIPPED TO YOUR FRONT DOOR . i just got a stage 2 can and it was $124

[bullett]

I believe they changed the sprocket size in 05. 06 stock size is 14 for the front not 15 like the older ones.

[rcatvrider]

Get the sparks key and a 13t front sprocket. I ride all trails and the 13t is great.

[MidnightBlade]

yea i have an 05 and my friend has an 06 they both had the 14t front sprocket. then id get a stage 1 cam (they are built for bottom end power) then a dyna tunable cdi box. id stay away from the advance keys.

[rcatvrider]

Originally posted by MidnightBlade
id stay away from the advance keys.
Why? It's plenty safe on a stock compression motor and a hell of alot cheaper than a programmable ignition.

[MidnightBlade]

i know a few people who have run them and they all sheared off, i dont know if the 3* key is better but i know the 6* shears VERY easy. as soon as you get a backfire it is GONE. even the stock key on my dads dirtbike shears when it backfires, and it is thick. yes we all had our flywheel tightened down good and tight. so idk whatever you like, i may try a key before an ignition idk. just dont like a half sheared of key in my motor

[1dirty400ex]

i will be getting a cam very soon, but for now i am interested in the sparks key and droppin a tooth on the front sprocket. im only seventeen and still in school so i have a part time job paying a fourwheeler payment every month, which doesnt allow me to invest a lot of $ till this summer.

btw, front what i read on here, most people say a cdi box isnt good for your quad. My friend had a dyna tech that kept trippin and messin up his z400. but idk?

thanks for all the answers guys, yall've been great help. Any more ideas or comments on how to make my quad gain bottom end would be greatly appreciated.

Thanks, Kyle

[rcatvrider]

Originally posted by 1dirty400ex
i will be getting a cam very soon, but for now i am interested in the sparks key and droppin a tooth on the front sprocket. im only seventeen and still in school so i have a part time job paying a fourwheeler payment every month, which doesnt allow me to invest a lot of $ till this summer.

btw, front what i read on here, most people say a cdi box isnt good for your quad. My friend had a dyna tech that kept trippin and messin up his z400. but idk?

thanks for all the answers guys, yall've been great help. Any more ideas or comments on how to make my quad gain bottom end would be greatly appreciated.

Thanks, Kyle
I know what's it like wanting so much for the quad but having so little spending cash haha.

As far as a cdi goes, the added revs are pretty much worthless on a 400ex motor, but the timing curve change may be helpful. Might as well get a advance key in that case.

[MidnightBlade]

Originally posted by rcatvrider
I know what's it like wanting so much for the quad but having so little spending cash haha.

As far as a cdi goes, the added revs are pretty much worthless on a 400ex motor, but the timing curve change may be helpful. Might as well get a advance key in that case.
that is why i suggested the tunable rev box you can change the rev limit and the timing curve, they are totally adjustable for all the things to tune

[1dirty400ex]

so after researching on the timing keys i am positive on getting one. But which is better, srp or curtis sparks?

[rcatvrider]

I have the srp, it was cheaper at the time. They are basically the same thing so get whichever you find cheapest.

[1dirty400ex]

alright thanks for the imput...anybody know the best sprocket( as far as durability and life), and i would need a 13 tooth sprocket, right?

[rcatvrider]

Yes, get a 13t front sprocket. I am running a renthal but have also run cheapo primary drives without a problem. Only one that has stripped on me is a sunstar.

[1dirty400ex]

when i change the sprocket, will i have to take links out of the chain?

[rcatvrider]

Nah, I'm still running a stock chain.

[1dirty400ex]

thanks man