A lil help requested...

[hardtime]

Here's the prob...

My 400ex is having a lil "stall" problem when its "gunned" or at low rpms and power needing situations. Once a higher rpms are obtained, everything is fine. I was told maybe the jets but I'm a newbie when it comes to those things but I'm ready for whatever is needed. Everything is stock, as far as I know. 2000 400ex was bought used. And another quickie, I replaced the spark today after it wouldnt start for me today (flooded?) but anyways the new sparkplug was black after about a minute of running when I checked it. Running too rich?

Any help is greatly appreciated!

HaRdTiMe

[Davids440ex]

if it was black its runnig to fat
if its a white powder to lean
you may need to lower the jet a little

[400exInMI]

when you ran it, did you drive it, or just gun the engine. you need to ride it to see how it is actually running. ride it for about 10 minutes accelerating hard and soft. Pull the plug, if it is still black, consider changing the jets, if it is dark brown to brown, leave it alone, if its white, pull the jet and put a new 148 one (stock jet about $4) in and see how it runs. if the bike is all stock, you should not change the jets at all....stick to the 148...kep in mind, if the bike is not ridden, just letting it idle or revving the engine, it will naturally run richer than normal.

[hardtime]

The "stalls" and "cutouts" occur all the time, from cold to hot engine conditions. I usally have to donwshift to get the higher rpms then its all fine. I was told to adjust the jet but like I said, a newbie on carbs. On the spark plug, I just gunned it a few times and let it idle before I removed it.

[400exInMI]

ride it and check it again......go to www.helminc.com, you can pick up a service manual from them, they make em for honda.....

[hardtime]

Okay, I rode it for awhile and removed the plug. -- Jet black in color. What do I do next?

[BornOnFire]

First thing, do what "400exInMI" said. Get a manual. You may have to adjust the valve clearance before you mess with the carb. If the valves are far out of adjustment, you may suffer some the same symptoms you are describing. Since the bike is completely stock, I would start there. Are you running with the airbox lid intact? Is the air filter stock? Have you cleaned the air filter? More info please!


:D

[JabberJaw]

Jet black in color. What do I do next?
I'd paint the rest of the bike the same color to match!

[hardtime]

Air filter cleaned and everything is stock. Still running factory tires so there isnt much riding on the bike yet.

[400exInMI]

you may want to consider taking it to a dlr, cost some bucks, but will save you time and a headache.