2005 400EX /W 05 450R Carb

[rsheppick]

Hey all.

Decided to take my extra 450R carb and put it on my 05 400EX.

I modded the intake boot and got everything installed.

We are about 5000FT here in Salt Lake City, Utah.

I put in a 160Main Jet 42 Pilot Jet and 2nd clip on stock needle and 2 1/2 turns on the A/F screw.

The bike starts some what okay, mid-full throttle its fine.

With the air filter removed you can hear the motor backfire or some funny sound like it had a hard time running. then stumbles on its face and stops. It seems like it sort of having a hard time with very low RPMs. Keep in mind with the stock carb its fine.

I was told to go bigger on the pilot so i took my 450R carb from my 450R and put it into the 400EX my other carb has 162 Main 3rd on the HRC needle and 150 pilot jet with 2 1/2 turns on the A/F

Same thing...


Is it really possible that the smaller 400EX thats stock requires more fuel than my heavly modded 450R?

going bigger than a 50Pilot seems unreal ..

[rsheppick]

Anyone?

[Buffalo400]

very interresting... I'm doing some researchs of jetting setups for my new 450r carb to fit in my stock bore 400ex....

Somebody told me that the HRC needdle is richer than the stock.... so, your needle setting should be different between your two carb..... maybe you should go on the third notch on the stock needle...

Also, 440ex owners use 48 pilot jet.... maybe you should go with a 45 is the 42 run lean.... but before, do you turn out your fuel screw a little?

I think you are near to the best setup!

[rsheppick]

I have tried a 38 Pilot a 42 and a 45 and a 50.

It has no effect on the backfire sound the motor gives like it cannot burn the fuel in the motor.

It is at idle the problem happens.

I have tried even the 4th clip on the stock needle and multiple differnt adjustments on the AF Screw. I have even put it all the way in and it doesn't have any affect on the setup.

[Buffalo400]

Do you have a k&n filter and open air box... try this..... I think the bike need more air....

I can't see whats your problem... maybe you have a leak with the air boot or air box boot... or, are you sure you have no leak at the hot start cable hole....

after, you should clean the carb......

When your problem will be solved, you will be so happy of your new poneys....:macho

[rsheppick]

Originally posted by Buffalo400
Do you have a k&n filter and open air box... try this..... I think the bike need more air....

I can't see whats your problem... maybe you have a leak with the air boot or air box boot... or, are you sure you have no leak at the hot start cable hole....

after, you should clean the carb......

When your problem will be solved, you will be so happy of your new poneys....:macho

I can do a better job at closing off he hotstart. But i have something in it that I thought would do a good job.

It has a K&N on it. I even removed the whole airbox from it and tried letting it idle without an airbox.

The carb has been cleaned keep in mind I have tried 2 differnt 450r carbs both have same issue.

[Buffalo400]

You're right. Your carb is clean, sure....

Some people here, their 450r carb run fine at idle... sure, they have 440 but they run 48pj.... I know somebody with a ported 416, his 450r carb run fine... Another run fine on his stock 400ex... I e-mail him and I wait the answer.... I'm sure it' possible to fit it.... (I wish because I bought one today!)

If a 440 run a 48, a 400 should run about a 45. maybe a 42... if you increase your Idle a little, what happen? Let it idle a while (If he wants) and with a plug test, check if the plug is fouled or lean...

Try with a stock filter, you should see what happen.... You should see a difference and see if he's lean or rich....

[mikeminyard]

I have a 406 at 11:1 with hotcam stage 2, hmf exhaust and gt thunder rev box. I found that the best pilot jet for me was the stock one for the 450r. I ran the stock needle at mid setting, and the main I think is a 175. I can't remember for sure. I blocked off the hot start and can't use the choke at all. It is hard to start with out a little gas. It dies about 3 times and then idles. Once the engine warms up though it is perfect.

[Buffalo400]

Thanks buddy for your setup. How is your fuel screw?

Are you enjoy of your carb?

[mikeminyard]

My screw is about 2 turns out. I don't have the exact amount because I just turned it a tiny bit at a time until it ran right. They key to getting the carb set right is adjust the jetting once it's warm because the carb is a bit finicky while the engine is cold.

The carb itself is an awesome upgrade. More power, better throttle response, and it really lightens the feel on the thumb throttle. This is especially nice for people who tend to get cramps in their thumb. My wife loves it, and I can tell you, it really makes my 250r thottle feel heavy.

[Buffalo400]

Thanks you so much... :cool: