Help with dune gearing!

[mattl31]

Hey guys, I was wondering if some of you with a little more experience could shed some light on recommended gearing for my 400ex.

Specs:

2000 400ex
11:1 Wiseco - 50/50 pump and 110 gas
Stage 2 Cam
Ported Head
FMF Powerbomb
FMF Ti-4
15F/38R Gearing
ITP Sandstar Rears
200lb Rider

I'm just curious if I should try dropping a tooth in the front to shorten up my gears a little bit.

As is, first gear is almost too short to even use at the drag strip, so all my buddies with 450's are saying that I should be launching in 2nd. However I've tried and 2nd will bog the motor even if I leave near the limiter. I understand that the 450's are geared a little shorter in the transmission which might be why they dont have any trouble leaving in 2nd. I'm wondering if dropping a tooth on the front sprocket will shorten up my gears a bit and get it so I can launch in 2nd. Also, as is I run out of power (not gear) in 5th at the dunes. Thinking that the shorter gearing will help me be able to use more of my gears in various situations.

Shoot me all your thoughts guys! Thanks!

[honda400ex2003]

easiest thing to try would be a 14. that would get you launching in 2nd and would let it rev out better in 5th for sure but 1st is pretty quick.

something that isnt so radical would be a 39 rear instead and would be a compromise between your 15 and a 14.

steve

[mattl31]

Originally posted by honda400ex2003
easiest thing to try would be a 14. that would get you launching in 2nd and would let it rev out better in 5th for sure but 1st is pretty quick.

something that isnt so radical would be a 39 rear instead and would be a compromise between your 15 and a 14.

steve

awesome steve, thanks!

i think ill try out the 14 front since its cheap and easy...see where that puts me. as far as trails go at the dunes i rarely ever leave 2nd, so maybe ill be able to use 2nd and 3rd with a 14 front.

[honda400ex2003]

hopefully cjm will pop in, i think he runs dunes a bit or at least alot of sand roads and stuff. he recently went down a bit too and has some good info on it.

i think you will be happy with a 14 though if you want it lower. you will def be able to run 3rd if you used to run second.

steve

[ridgeracer]

Bkelley ran 13 in the dunes for a whille i think. Haven't seen him on recently though, he's been working on his Mustang.

[togup]

I run a 14 when duning due to the power robbing sand, the front sprocket is easy to change out and like you say cheap.I step up to 16 for speed runs.

[sixer3]

you'll definitely be happy with the 14, all i ride is dunes!

I also had an 05 which has different trans ratios and with similar mods to yours I ran a 13/36 gear ratio for anyone with an 05+ that reads

[CJM]

ya know my pager just went off steve...you beep me for this lol??

I ride a mix of sand dunes and sandy roads in a sand pit. I do hill climbs, race on the sand trails and go thru what I like to term hard packed and soft packed sand depending on where we are at the pit.

You can see the specs of my quad in the signature, which may help ya.

I originally had 15/38 and found it ok but not enough speed I thought and I was constantly going from 2nd to 3rd back and forth. It had good power but just not enough lowend imho.

I swapped to a 16t front and it was to much topend and I lost the lowend like crazy. Yes if I dragged it ruled, I could do close to 80mph or better I would guess. Running against 450s and they would pull on me for a few secs and then I would wail past them.

I then got a 14t front and found while its nice I tend to run out of gears way to easy-1st is near useless and 2nd isnt much better-what it did help was I was mostly in 3rd and 4th and didnt have to switch often-bad news was that your in too high a gear sometimes, and with the stage 2 cam making more power higher up you rev out to easy in the lower gears.

I finally decided on 15/39. This according to http://home.earthlink.net/~gellett/400ex.htm the 400ex gearing calc (change the rpm to 9100 btw) yields me a mixture of the 14t/15t fronts.

Otherwise if that doesnt help me I got more problems than I think cause so far I can rev out 1st and 2nd WAY to easy with a 14t, even on flat ground its insane how fast I go thru the gears. Infact after doing the 14t I find it just seems I run out gears to easy, maybe its the stage 2 cam, maybe something is amiss with the quad (stator or a carb issue would be the culprit if it cuts out on higher rpms btw) I just got my new rear 39t the other day but havent put it on. If its warm enough this sunday Im going and Ill find out and if I remember Ill report back.

[sixer3]

Not sure where you guys ride of course, I rarely use first gear anyways unless its to take off from a casual stop....if that.

I ride at glamis and gordons (imperial sand dunes)

I haven't had my ex in a few years but the 14 allowed me to get into 5th and pull it nicely across the longer bowls.

Our group is a mix of old vw buggies, long travels, dirtbikes etc. we get cruising pretty good and being able to pull 5th gear around a wide open bowl reallllly helps in my case.

In any kind of hill shooting or drag I've always launched in second

I did have a rev-box on my bike I believe the one from Alba, if that made a difference or not, I'm unsure I guess it could help keep me in the gears longer

I will say my 05 was a much better duner with the 13/36 though this is not helpful for the current o/p though

[JOHNDOE83]

For dirt drags I use 13/39, it spins paddle tires really well in high gears, maybe even try 12/39.

[2001400exrida]

i run a 14 tooth at badlands and it's perfect in the sand.

with the 15T i could barely accellerate in 5th gear, 4th was sluggish to. Now that i went down to 14T in the sand it can pull through 4th and 5th better. Still not crazy powerful but it pulls better.

with a 16T front CJM i have to say that the 450 would spank a 400ex all the way up to 75mph. the 450 would be so gone, it would take 5 miles for the ex to pass it going 80mph haha.