cams and piston

[dirtman91386]

i just got done doing 400ex boot mod and i still want more power...im thinking about doing cams and a higher comp piston? what piston and cams do i go with? any good prices out there? if i go stage 3 cam how much low end am i losing? i just want to beat my buddys kfx and still have a reliable ride. sry for all the ? just trying to figure out what to do

[ifixtheyride]

What does your buddy have that you don't? If you want to spend that kind of money like cam and high comp piston be prepared because it is not going to be reliable it will need more maint. If your after cheaper quick power get the $15 13 tooth front sprocket and maybe look into an FCR carb other then that when you start changing cams and pistons be prepared to be taking it apart often and replacing parts

[cataway]

Originally posted by dirtman91386
i just got done doing 400ex boot mod and i still want more power...im thinking about doing cams and a higher comp piston? what piston and cams do i go with? any good prices out there? if i go stage 3 cam how much low end am i losing? i just want to beat my buddys kfx and still have a reliable ride. sry for all the ? just trying to figure out what to do

having been were you are now i know your pain ,''give me more power'' it is indeed contagious.
yes you can pump up the power some different ways,you did the boot which is a good move and just about the cheapest HP your going to get, a little more can be gained by replacing the base gasket with a single layer one ,the one from a DRZ is what to look for or just separating the one you have so that you use just one of the three parts ,that should get you 12:1 or very close to that .
then it starts to get expensive cams , higher comp piston, porting and a better carb are some things i see in your future.

i just happen to have a set of cams i'm no longer needing ,they are how ever set to a different degree than what you want for a stock crank but that can be fixed . BTW these cams are whats called stage 2. hot cams never ever made a stage 3 they really never made a stage 2 but thats what its called when the new and the old get mixed to the right proportions.

PM me for a price ,and were you live.

[dirtman91386]

my buddy has a kfx 400 with a biggun full exhaust and he also did 400ex boot this weeekend. i think thats the extent of his mods...cause are bikes run the same pretty much....and when you say cams will bring a rebuild what do you mean? new piston new, head, valves? i think im leaning more twards cams and a fcr carb what you think?

[cataway]

cams and a high comp piston will wake it up , porting is good to all thats really needed is a good clean up of the ports ,the head flows good the way it is so it does not do much good to cut much out , next best thing is bigger intake valves, with that is not hard to come up with 40HP, on stock bore.

[dirtman91386]

do you think with a good tune ill be rebuilding it all the time? or it should last awhile?cause i think after the cams and piston ill be done modding it

[cataway]

do you think with a good tune ill be rebuilding it all the time?
or it should last awhile?


cause i think after the cams and piston ill be done modding it.the one part that most are having trouble with are the intake valves, put in extremely good valves and you may never have to touch them again . the one valve i feel good about recommending is RHC valves. the only place you can get them is eddie , find him on thumper talk

[dirtman91386]

whats your oponion on kibble whites?

[cataway]

second best

[cataway]

funny thing about KW 's and RHC valves if struck the KW's tend to brake off RHC tend to bend

[twincat800]

I think you should just get the fcr39 carb and see if your satisfied with the power and engine response you get from that, makes a big difference and you could find a used one.