416 lacks bottom end power

[400exracer511]

i just rebuilt my ex a couple months ago and put in a je 416 and a stage II hotcam and i know that is a top end cam but it feels like i could get more bottom end power. I get the feeling its a jetting problem so which jet do i adjust to get the bottom end better

it has a 165 main and 2.5 turns out on the air/fuel screw. needle and pilot are stock

are there any other things you guys can think of that would make the bottom end lack?

[cals400ex]

air box lid on or off? you know what elevation your at?

[400exracer511]

no air box lid wite bros e series slip on 12 discs k&n filter not sure on the elevation im in iowa though

[dariusld]

When I first did my cam(stage 2) and high compression piston, I thought I did something wrong. When I rode it back to back with our other 400 with pipe, I thought it felt like a dog. But when I race with other bikes, it flies. My son likes the stock cam to wheely with, but the rest of the time he wants the cam. It just took a little while to get to use to where the power is at. Where the stock cam stops the stage 2 just keeeeeeps pulling.

[speedy400]

hmmm mine grunts it's way through all gears no matter bottom or top end. my mods-
open box, fcr39mm, my porting and polishing, 416 10.8 comp,hotcam stg2, powerbomb header, and a hmf slipon. so basically only diffrence is porting and a fcr39mm....I'd say do some plug chops and get that jetted perfect.good luck-darren

[cals400ex]

what gearing you running with what size rear tires?
do you have your throttle cable adjusted properly?


i know many may disagree, but when my buddy switched from his R4 slip on to his full HMF, he got a huge gain. i would say it was several bike lengths drag racing. just something to consider.

[speedy400]

Originally posted by cals400ex

i know many may disagree, but when my buddy switched from his R4 slip on to his full HMF, he got a huge gain. i would say it was several bike lengths drag racing. just something to consider.
true, but a full system would usually be more mid-top compareds to a stock header. If he's seeing little amount of bottom end, seems stocker would be best, and the wb slipon dis system would also be a good setup for bottom-mid, maybe that stg 2 cam is just throwing off your whole setup.. having everything setup for bottom then a mid-top end cam. Just an idea. Also maybe your loosing compression, that'd take out a nice chunk of your low end grunt.-darren

[cals400ex]

Originally posted by speedy400
true, but a full system would usually be more mid-top compareds to a stock header. If he's seeing little amount of bottom end, seems stocker would be best, and the wb slipon dis system would also be a good setup for bottom-mid, maybe that stg 2 cam is just throwing off your whole setup.. having everything setup for bottom then a mid-top end cam. Just an idea. Also maybe your loosing compression, that'd take out a nice chunk of your low end grunt.-darren


see, the low end power he gained was just as good as his mid-top end gain. i have no idea why. the stock header had the the welds grinded out too. i was really impressed. now, it doesn't flow nearly as high as my x-6 does, but it produces power everywhere. i can't say that about my x-6 either. this kid has a stage 2 and a smaller bore, lower compression piston than me.