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procircuit406ex
06-15-2007, 10:28 PM
Im looking to get alot more throttle response out of my 400ex..what would you all suggest? 450R carb?

Thanks,
Tyler

procircuit406ex
06-16-2007, 09:02 PM
Any oponions?

Tyler

CRich[814]
06-16-2007, 09:11 PM
current mods, gearing, and tire size would help.

flauge
06-17-2007, 12:06 AM
I noticed better throttle response after i put my 450r carb on..
Also if you have'nt done it you could also take the choke out your stock carb. That'll give you better response too.;)

procircuit406ex
06-17-2007, 02:21 AM
Procircuit slip on is the only mod to the motor as of now, 14/38 gearing, and 20" Razr2's

Im looking for more snap like at idle if I hit the throttle or if I hit the throttle goin down the trail

flauge
06-17-2007, 02:32 AM
Taking out the choke will help out with the snap you're talking about. Plus its a free mod so that makes it even better!:cool:
I did this to my stock carb before i got my 450 carb and it helped a bit. At idle you could hit it and it would turn right up, no hesitation. You might need to go up to a 40 or 42 pilot if you do it though since you have a pipe tho...

GPracer2500
06-17-2007, 10:02 AM
A well tuned FCR carburetor is probably the ultimate source of throttle response. I've ridden 400EX's back to back: one with a stock carb (choke removed), one with an FCR. The difference is dramatic. The FCR equipped EX would jump at the throttle while the stock carb would lazily respond when it was good and ready.

The FCR EX actually felt a lot faster because of the throttle response even though the other EX had more engine work (both had cams but the FCR bike had a stock piston). When we raced them up the hill we confirmed that the non-FCR bike did indead have more HP. The FCR bike sure felt nicer though.

Unfortunately FCR's are not cheap and they can be a bear to settup properly (not always but sometimes).

JW450R1
06-17-2007, 10:03 AM
What size main jet?.Is your air box lid on or off.

procircuit406ex
06-17-2007, 11:27 AM
Idk about the jets, I run a full airbox

JW450R1
06-17-2007, 11:33 AM
Did u rejet when u installed the slip on on?.
You can get a little more from changing the tire size,and sprockets too.How about a cam?.

procircuit406ex
06-17-2007, 12:04 PM
It came from the dealer with a Procircuit so no I didnt rejet..I run 20's, 14/38 gearing and when I can get some cash 13/39, and I have considered a cam but once again, the money plays an important role

Tyler

mod440ex
06-17-2007, 01:58 PM
go with efi