Lost top end!!Help!!!

[BornOnFire]

Ok. I did a lot of work today on my 400 EX. I re-jetted using a 165 main and a 40 pilot. That's it for the carb. I then adjusted my valve clearance, and ground out the welds on the head pipe. Last but not least, I added a slip-on WB E-Series. Of course I couldn't wait to ride it and fired it up. It had some trouble idling at first so I adjusted the fuel/air mixing screw and it held at a steady idle.

I then took it out for a spin and once I got into the open, I punched her and red lined up to 5th gear. That's when the top end just died on me. It got up there for about 10 seconds and then cut out.

I thought I was going to stall for sure so I slowed down. After I came to a stop, it idled fine and had some throttle response but at full throttle, I get nothing. I am a little worried. Any one have any advice? Do these symptoms sound familiar? Please Help!!!!

Laters,



:huh

do you have your airbox lid on? mine did that and it was too rich.i took off the lid and it ran fine. went too a 155 main and no problems

[VegasEx'r]

Yeah, it sounds like you might be running a bit rich.

[BornOnFire]

I have my airbox on but it is heavily modified! 18 1" holes! Could my main jet be too big? If I am running rich I should be able to tell by the plug!

[VegasEx'r]

Originally posted by BornOnFire
I have my airbox on but it is heavily modified! 18 1" holes! Could my main jet be too big? If I am running rich I should be able to tell by the plug!

How does the plug look?

[BornOnFire]

How does the plug look?


I'll let you know tomorrow! I'm too f'in tired to mess with it tonight after working on it all day.

I guess that the "running rich" theory makes sense though. Due to the fact that it cuts out when I hit WOT. All other stages are good. I must have fouled the plug. That explains the short burst of adequate performance before things went wrong. Thanks for the help!

I'm crashing!!:o

[bama400ex]

make sure sure the carb is still in the boot good, probally not it but it wouldnt hurt to check. thats the only thing i could know of it being if it ran right at first. maybe it wasnt in there good when you put it back on and it finally fell out.

[BornOnFire]

I never removed the boot at the engine. I only removed the airbox boot. I am wondering if I should go to a smaller jet! Like a 155 instead of a 165. We'll see I guess.... What a PITA.:mad:

[VegasEx'r]

Originally posted by BornOnFire
I never removed the boot at the engine. I only removed the airbox boot.

What do you mean you only remover the airbox boot? If the boot between the airbox/filter is gone or not installed properly, you will have the kind of problems you are explaining.

[bama400ex]

well got it fixed yet? let us know what it was.

[BornOnFire]

Actually, I am still messing with it. I had to go to the dealer twice yesterday to get different sized jets. I have yet to install the 155 and leave the pilot jet stock. I think that may work!

I will be back to report.:D

[BornOnFire]

Utter complete bull$hit! I have tried every Frigging jet possible with $hit results! I am at a loss. I guess I will have to be a puss and take it to a dealer! I am defeated! Any suggestions? other than shooting myself?

:mad:

[Rastus]

get a New plug?Do you have your choke off? Is there anything blocking gas from the carb?Whats the stock jetting?

[bama400ex]

maybe its something to do with the ignition? i dunno.

[Leo]

before you take it to the dealer put your 15 tooth sprocket back on to make sure it's not the rev-limiter you feeling

(it's a very different sensation hitting the rev limiter w/ a slip-on vs. hitting it with the stock pipe)..

Leo

[BornOnFire]

The stock jet is a 148. I tried a 152, 155, 160, 165, and a 170! All with the same results. I have put three different plugs in and still no positive results. I highly doubt that it is the rev limiter but I will try replacing the sprocket and see how that works. I am no carb expert but I am becoming one really fast! This thing is kicking my *****. I am wondering if I should just sell the damn thing! AAARRRUUUGGGGHHHH! @*%&#$ :mad: :mad: :mad:

[yellowrider]

lol poor baby haha.......

my friend that wrecked his raptor fixed it .. well let me get to the point he bought a white bros r4 and for 1 full week he couldnt get anything right finally he just took it to his dealer and its been there for two weeks cause the shop is busy ... oh well it just reminded me of him we laughed at him for so long i was even beating him on black top ... and i have a 400ex loL! oh well i hope you get her fix

[2qk4u]

yeh that goes to to show Rapturds are'nt all they are cracked up to be. I've dusted a couple also and it wasnt rider error.

[RideRed04]

Try the stock main jet again. If your plug is fouled, you need to replace it. Your pilot jet doesnt have anything to do with the WOT runs. Leave in the best one that works there.

[BornOnFire]

I tried the stock main jet again with no luck! I am wondering if the lifter and spring on the needle has become detached. Hmmmm. I will have to check that his afternoon..................

[BornOnFire]

Found it! The throttle arm became detached from the throttle valve and would not let the needle adjust fuel accordingly. Man, the sweet smell of burning fuel gave me a chubby! I have it running but now I have to tune it to the proper jet. I am getting a little backfiring and I presume it to be a little lean. That's the easy part! I took it for a ride and if you looked really close at me, you could probably find a tear in my ear! :p

Thanks for all of your help people!