stock vs. aftermarket

[jsmith2232]

I bought a 04' 400ex, stock my gps clocked 64.5 mph after i added an fmf power core pipe, k&n jet and filter kit, and rev box i clocked it at 57.5 mph both times i did this the air was about 30-40 degrees out, i did however notice much more torque, but why did this slow me down and how can i get my top end back up with out suffering much pick up?

[jsmith2232]

ive read some on changing sprokets,,, what will get me what i want... is there anyway i can achieve 65-68 mph and still be able to pull off the ground in 3rd gear.? please help asap. thanks

[blue416ex]

try a 15 tooth front sprocket with your stock rear but youll have to ride it a wile to get that chain tretched then turn it back to al the way in adjustment n slap it on if you try with a fresh chain cut for a 14 tooth front it wont work a 15 or 16 is my recomendation but with a 16 you may not be able to lift it up in 3rd

[sprtrx300ex]

the stock front sprocket on a 400 is 15. Try a smaller rear.

Do a search, theres alot of info on this subject

[SHARPMACHINE]

This one does not make sence... Their has got to be something wrong. Do a couple of plug checks to make sure you are not running lean. Also try jetting it for no air box lid??



Just my .002 good luck and let us know....:cool:

[jsmith2232]

it seems my rpm is getting up there. i put my stock cdi box back on for a try and the new one is definetly getting me higher rpms, i'll try the plug check and see if that helps... what is the best choice for a replacement plug?

[Fortman_400]

i always use NGK plugs in all of my vehicles.. but Champion or any other big name brand should work good
i dunno how u could be going slower with higher rpm's while the gearing is the same, its not mathimatically possible,,, lol lol

[jsmith2232]

yeah i hear you, i don't understand it either. but i did check it with the gps and i've tried topping it out 3 different days now and it constantly shows 57-57.5 every time.

[Greg Z]

did you jet your carburator because that Makes no sense you should be going faster with stock sprockets..

[jsmith2232]

the honda dealer i took it to claims they jetted it to the recommendations on the pipe. the only 3 things that i have narrowed it down to is 1. maybe the rpm's are too high and i'm not getting peak horsepower. 2. it is recommended to take the airbox snorkel off and it isn't. and last. maybe the clutch is slipping...I really don't know these are just suggestions that the dealer is throwing out at me...do any of these make sense and make that much of a difference?

[SHARPMACHINE]

Does anyone know if it is commen to get 64.5 out of a box stock 400?? Maybee you got a bad # to start with. If you are turning more rpm in high gear and going slower you are either 1. using differant gearing (i.e. tires or under inflated tires, sprockets etc..) 2. slipping your clutch 3. spinning your tires or 3. Smoking the good stuff:devil:


and if the clutch is slipping it should be noticable.




Good luck keep us posted :cool:

[400ex ryder]

How much do you want for your 600 REV?
How much for the 250r (basket case)?

[jsmith2232]

I checked it today and pulled a 64.8 on the same gps and conditions, i think maybe i was slipping a bit when i clocked it the last few times...

how much more performance do you think i'll get with a powerbomb header added onto what i got?

[SHARPMACHINE]

They say it will help, but I would be looking closely at your clutch. If it was slipping at top speed than it is prob. slipping at hard acceleration evan more.


Good luck :cool:

[jsmith2232]

I got it in the shop now and am having the powerbomb put on it tomorrow and ill let ya know if that helps.

[400exrider707]

A header wont make your quad any faster. It might help you get to top speed faster, but if your clutch was slipping the header will only make it worse.

More power + slipping clutch = going no where.