[tyler123456789]

hi, i’m new to the forums and need some help with my 01 honda 400ex,
i just gave it a nice wash and previously ran it about 2-3 days ago. i went to start it after i washed it and it didn’t want to stay running. i figured this was because it was cold and it’s jetted so it was normal, but i didn’t have the time to stay out there and baby sit the throttle to keep it going. i went in and ate dinner. came out about 30 mins later and went to start it and it didn’t want to start at all unless i was over half throttle. i got it to stay started with lots of throttle but it was popping like crazy. some big some little and a bit of blue smoke coming out tailpipe. every time i let off throttle it dies immediately with some unpleasant noises

all that’s done to it is uni airfilter, jetted, and pro circuit pipe

 

[SlammedRanger]

Sounds like its flooded real bad. Where you pumping the throttle or choking it the whole time?

 

[tyler123456789]

yes both, i would change the choke every time from half to full. when i did no throttle it acted like it was started when the starter was going but when i let off starter it quit. going to let everything dry out and try again tomorrow i will let you know what happens

 

[SlammedRanger]

Pumping the throttle is gunna flood it. Using the accelerator pump to prime the engine is just covering up a jetting issue. Putting a bigger pilot jet in will solve the problem. Cold starting the 400ex with the stock carb is very finicky. I have found full choke and throttle as soon as it fires to keep it running is the best way. Once it warms up a bit you can turn the choke off and then eventually let off the throttle and it will idle. A different carb changes this 100%. My fcr i can start in negative temps with choke first time and it will just purr and idle up to temp as i slowly back off the choke. Just a characteristic of the carb choke design i think. But keep us posted if it starts better after it unfloods itself after sitting for a while.

 

[mrbb]

check your oil and make sure you didn;t get fuel into it!

 

[tyler123456789]

started it up again right now and was perfect until it got warm after about 30 seconds. it started bogging and popping again

 

[SlammedRanger]

Your 100% sure choke is off correct? Forward is on. All the way back is off.

 

[tyler123456789]

yeah, everything works fine after it’s warm, idles fine and everything runs great. but whenever i make choke adjustments when it’s warming up it does the popping and bogging. could it be a little water or debri in my bowl that gets sucked into the jet every once and a while? or maybe the coil? i just need to know what it is and fix it so i can sell it

 

[tyler123456789]

yes, once it’s hot it’s fine. full choke to start. then it starts. wait about 30 seconds and it pops and starts bogging. i have to keep pumping the throttle more then half way. then i put it on half choke and it immediately wants to die but i if i push the throttle even more it stays started and popping slows. and then no choke and it pops just a little. sound like popping out of air box and exhaust. then after it’s done popping it rides fine and idles fine. any ideas of what it might be.

 

[Goober]

Sounds like a bad choke valve but I don’t see one on the parts diagram

 

[tyler123456789]

okay everything is fine now. i think it was flooded super bad like you said and just didn’t have air to mix with

 

[SlammedRanger]

The only time i have ever had one caughing back through the carb it was a stretched timing chain causing the timing to be off. It would start real sluggish and then start popping through the carb and sometimes through the exhaust. Only did it on cold starts and would run clean otherwise. Upgraded to a crf450 timing chaina and problem was solved.

 

[tyler123456789]

okay thank you for your help. might save the timing chain for the new owner lol.

 

[SlammedRanger]

No problem! Glad to help!