highly modded 400ex w/ 450r carb jetting ??'s

[feelthisroost11]

i have a 440kit, 05' 450r carb , j.e. 11:1 comp. piston, airlid removed, uni filter, ported head, hot cam stg 3, fmf power core 4 slip on, stock headers , i have a 200k. main jet, stock pilot, stock clip position, wont idle, had a backfire out of the carb, sounds like it choking out. plug is dark grey. please help.

what 450r carb is best for the 400ex?

450r:

-04/05 carbs are 42mm

-06+ are 40mm FCR carbs.

[feelthisroost11]

i have a 42mm already , i just can't get it to run right. i listed all of the symptoms above. any help would b appreciated.

[zrpilot]

Originally posted by FoxHondaRider
what 450r carb is best for the 400ex?

450r:

-04/05 carbs are 42mm

-06+ are 40mm FCR carbs.

-04/05 carbs are 42mm are the ones MOST people run

[zrpilot]

Originally posted by feelthisroost11
i have a 440kit, 05' 450r carb , j.e. 11:1 comp. piston, airlid removed, uni filter, ported head, hot cam stg 3, fmf power core 4 slip on, stock headers , i have a 200k. main jet, stock pilot, stock clip position, wont idle, had a backfire out of the carb, sounds like it choking out. plug is dark grey. please help. When you installed this, how did you handle the choke enrichment circuit? Is it possible that it is on?

[feelthisroost11]

where is it on the carb..i dont think i checked it.was it one of the wires you had to cut off

[zrpilot]

Check this Write up (http://www.exriders.com/vbb/showthread.php?s=&threadid=314423)

It is in the 5th picture down, in the lower left corner, kinda looks like a brass plunger pin. Make sure this is all the IN.

[feelthisroost11]

that brass plunger is all the way down. i have a funny feeling its something to do with the pilot jet and main jet i'm running.

[zrpilot]

Could be. The main does not have a huge effect on idle though (unless there is something goofy like it came unscrewed)

I'd look to pilot / fuel screw to fix idle problems.

How does it run otherwise?

[feelthisroost11]

those times i do get it to run o.k. it's way better than my stockie carb, descent response , but when i get it perfect it will unlock alot more power thru out the r.p.m. range.

[Wheelie]

Did you block off the hot start?


My setup is very similar to yours, with the exception that mines a 440 stroker not a big bore--also I'm running a full Yoshi exhaust w/a K&N.

At sea level: 50 pilot, stock needle position, 2 turns on the mixture screw and a 195 main jet--it runs great. My next trip to the dunes I'm going to try a 198 or 200 main jet. I don't see any reason why my setup would need anything richer than a 200.

[feelthisroost11]

tru' i'm deff. going to try the 50pilot, leave my 200 in and just play with the mixture screw a little bit , when u change your main jet, post back and let me kno how that went. thnks