400ex hard time starting, if at all...

[dripinc09]

Hey all so I have been fighting this beast for quite a while and thought I would ask some advice from you all.

I have a 99 400ex it has K&N filter, air lid on, 42 pilot, 160 main jets and Whitebros E-series exhaust.

I have a rough time getting it to start cold. Most of the time I am not able to get it running at all. But if I am able to get it running it runs just fine. I have replaced the sparkplug, new oem coil, and new gel battery.

It seems like the only way I can usually get it to start is if I have the battery charger set to small battery/gel/start mode. With it on start mode it will usually start right up, but often die and not start up again(if it doesn't die I can ride it all I want with no problem).

Any suggestions on what I should try/test/replace would be awsome!

I have tested the kill switch and it seems to be funtioning properly also.

[honda400ex2003]

i know you didnt list it but it would be easy to forget... does it have an aftermarket cdi. that seems to be the symptoms of an aftermarket cdi or a bad one.

how does your plug look also? might be too rich flooding it out.

how do you try to start it? choked full? pump the throttle w/o the choke?

im just curious before i start to give any suggestions or reasons for not starting.

I am leaning toward a cdi issue or a too rich issue.

a 160 with a filter and slip on is quite big up top and a 42 when using the choke would be enough to flood it down low.

if i may suggest something, do not use the choke the next time you try it. just pump the throttle 3 times and then try to start it up. if it pops over, give it 2-3 more and try it again.

please let me know your findings on it.

steve

[tri5ron]

I would certainly go with what Steve has suggested, and would add another question.
You say it wont normally start without the assistance of a charger.

Does this mean that only THEN, is when it will CRANK over properly?
or,...
are you saying it WILL crank over properly, WITHOUT the charger,....
but it just won't start up ?

If it will only Crank over properly, WITH the charger connected, Then you need to load test your battery, and verify that you have a good ground. (good grounds are commonly overlooked).

Also, since you do not list your location, here is another thing to consider, especially if you are in a cold climate.

400EX's are Notoriously "Cold Blooded Beasts".

They do take quite a while to warm-up, and idle properly, even in warm climates.

(I live in southern Ca., it is 68-70 degrees here today, and it would take at least 5 to 6 minutes for my 400EX to warm up, idle, and run correctly).
That's just the way they are.

If you are in very cold climates it will be even worse,
as well as,
your battery does not have the same cranking power when IT is very cold.

Just some food for thought.

[honda400ex2003]

good to see you back ron! I missed you around here :D steve

[dripinc09]

Originally posted by honda400ex2003
i know you didnt list it but it would be easy to forget... does it have an aftermarket cdi. that seems to be the symptoms of an aftermarket cdi or a bad one.

how does your plug look also? might be too rich flooding it out.

how do you try to start it? choked full? pump the throttle w/o the choke?

im just curious before i start to give any suggestions or reasons for not starting.

I am leaning toward a cdi issue or a too rich issue.

a 160 with a filter and slip on is quite big up top and a 42 when using the choke would be enough to flood it down low.

if i may suggest something, do not use the choke the next time you try it. just pump the throttle 3 times and then try to start it up. if it pops over, give it 2-3 more and try it again.

please let me know your findings on it.

steve

I have been trying both ways of starting, I have had more sucess with pumping the throttle 2 times and no choke.


I am not the origional owner of this machine and it had a 160 in when I bought it. I tried a 155 because 160 did seem a bit much and I got a backfire now and then. And I installed the 42 trying to resolve this issue(a local 400ex guy suggested it). I had a 38 and I had the same problem.

I just took the plug out and it was a bit carbon fouled. Took a wire brush after it and stuck it back in. No choke, pumped throttle twice then turned it over, fired, pumped glas 2 more times it started. I had to fight with it a bit but I was able to get it started and tore around on the road a bit and ran just fine.

Question, If it was somthing like a bent exhaust valve or somthing, would it run odd all the way through the throttle? Because it runs fine once it is running. Just a thought..

[Thumpin440ex]

400's have always been cold hearted pigs.. Mine was a pita start in the cold when it was stone stock, still is a b%^ch to start after I have modded it.. When its warm out, it fires rite up...



John

[Rohr397]

My moms 04 was this way. It was impossible to start if it was under 60 degrees. Usually took 10 mins before you could let it idle on it's own. And my Yfz had electrical issues so I ended up bump starting it the whole time I had it. Put'er in second, held in the clutch and rolled down a hill, when I gained enough speed Id drop the clutch and shed fire right up. No it's not the right way but it always worked.

[DragonGunner]

Its the cold weather...My 99' can be a bear also...may need a new battery...weak battery in cold sucks....Also what weight oil do you have in it??? The thicker the oil the harder it is to start in cold weather. I sometimes use 10W-30 in winter months, or turn a heater on near the engine to warm up the engine before riding, an usually with a battery charger on it too....lol.....but I've had it out in zero weather!!!