Plez help me with my NEW 406!

[exrider008]

i just got done my 406 rebuild and i went for a teast drive and if i go over half throttle it starts to pop like crazy. i put a 155 main in it could this be because i may be running to lean?
my plug is brand new and i only rode it for 10 min i took it out and it was whit on the top of the plug then the bottom half was black.

PLEZ help me out with this.:(

[hotrodbelair]

try a bigger main jet see if it helps any. im not sure how far to go up but just try a couple sizes bigger just to see if theres any improvement.

[exrider008]

ttt

[2004exrider]

That 155 is way to small. I'd go up to a 165 atleast, that should be right if it's too rich go down to a 160.

Jimmy

[exrider008]

Originally posted by 2004exrider
That 155 is way to small. I'd go up to a 165 atleast, that should be right if it's too rich go down to a 160.

Jimmy

thanks alot i will try the 165. my engine builder told be to go with a 152 and i told him that it would be way to lean and he sain that it would be perfect. so next time i gess i will just go with what i think.

[boricua]

half throttle is usually the needle clip, 1/2 - 3/4 throttle anyway. if it happens in that range try looking into that.......

2 pennies......

[Wheelie]

If the airbox lid is removed or modified, try a 160-165 main, and 42 pilot. Also lower the clip on the needle one notch if you haven't already done so.

[exrider008]

Originally posted by Wheelie
If the airbox lid is removed or modified, try a 160-165 main, and 42 pilot. Also lower the clip on the needle one notch if you haven't already done so.

i am a noob when it comes to jetting how do i lower the clip one notch?
Thanks for all the help guys!

[400exstud]

To move the needle, take the plate off of the top of the carb. This will give you access to the armiture that holds the needle. There are like three screws that must be removed to take the arm out. Then you have total access to the needle. Just pull it out and move the little e-clip down one position. Pop it back in and put it back together.

Trust me, it sounds much worse than it really is!

[GPracer2500]

Make sure to only make ONE change at a time when jetting. In this case, I'd take care of your main jet first.

[exrider008]

ok i got it to run perfect,but i just dont gey why its running perfect i have a HMF full exhaust, 406, and a K&N air filter and i am running the stock jet. i just dont get why the hell its running perfect on a stock jet. i even tried to go up one size and it was way to rich. but i gess if its running righ thats all that matters.

[GPracer2500]

Originally posted by exrider008
ok i got it to run perfect,but i just dont gey why its running perfect i have a HMF full exhaust, 406, and a K&N air filter and i am running the stock jet. i just dont get why the hell its running perfect on a stock jet. i even tried to go up one size and it was way to rich. but i gess if its running righ thats all that matters.

Where do you live? What elevation?

[exrider008]

my elivation is 95 feet i live in the lowest pont on vermont.

[GPracer2500]

Strange. You're using Keihin jets, right? Or, are they dynojet jets? They use a different scale.

[exrider008]

Originally posted by GPracer2500
Strange. You're using Keihin jets, right? Or, are they dynojet jets? They use a different scale.

nope it is the stock keihin

[GPracer2500]

It doesn't make any sense.

406 piston
K&N air filter
95 ft elevation
full exhaust

and a Keihin 148 main jet

:confused: :confused: :confused:

There must be some factor not accounted for because otherwise that can't be right.

[exrider008]

when i get into 5th gear it revs in and out almost like the clutch is slipping but i know its not. what could this be?

[coryatver]

that is your rev limiter

[exrider008]

no its not. i know what my rev limiter sounds like.
it dose it when im about 3/4 throttle

[GPracer2500]

Most likely it's your jetting. Probably a "lean surge".