Yet another starting issue

[Yorrick5]

Hey guys, I feel like a complete noob for posting this, but I'm at my wit's end and am not ready to turn to the dealer just yet.

I have an '04 400ex that doesn't have more than 10 hours on it (I bought it and promptly got sent out of state for work). My problem started shortly before I left and continues now that I've returned 6 months later.

I cannot get the thing to start. I'm getting good spark and the plug is wet, so I'm assuming the fuel is getting where it's supposed to go. I can feel the choke tugging at the throttle when it's closed, so I'm guessing that my air is OK. I drained what fuel was in the tank when I got back and replaced it with fresh. The battery is on a tender, and it's fully charged. And yes, the tank switch is on and stop switch is off :) .

It cranks just fine, and every now and then it'll catch, but won't start. Most of the time, regardless of what I'm doing (opening throttle,closing choke,closing throttle, opening choke, vice versa, ad nauseum) it just cranks with no indication that it even wants to try to fire.

The part that's bugging me is once in a great while, I'll go out there and it'll start up as soon as I hit the switch. I'll tool around on it, park it, come back the next day and nothing. Same situation. There seems to be no rhyme or reason for when it'll start and when it won't.

Tell me there's something I'm missing. I'm guessing you guys know the idiosynchrasies of a 400ex better than I do. I've owned a few ATVs in my life, but never had any problems with them (and didn't mod them) so I'm not technically proficient with them yet, though this Honda is making sure I become so. I was a tank/wheel mechanic in the army for 8 years, so I'm not afraid to get dirty if need be.

Thanks for any help you guys might gimme.


**edit**

Forgot to mention that it's garage stored and maintained at a fairly constant 70 degrees.

Also, I just hit it with a blast of starting fluid (my last resort), and it was completely ignored. Sigh.

[tryken]

Have you put in a fresh spark plug.

[AtvMxRider]

Try a new plug.

[rubiowner01]

I had the same problem, tried to start it one day wouldnt start for anything. I replaced the spark plug and it fired right up. So I would suggest you should really replace the spark plug, even if its not the problem, its not a waste...

[notfastenuf4me]

to me in my opinon it sounds like the plug is fouling undercompression which means if u pull the plug out and check it it will spark but the conmpression from the piston is puttin the spark out kinda like lightin a match and blowin the flame out

[mmartin]

My friend and I had nothing but problems with our 04's also. They would not start, fouled plugs and would not Idle unless the Idle was set really high. I took mine to the dealer and they played with the a/f mixture and made it a little better but it still was not right. We both put 42 pilot jets in them and fresh plugs and neither of us have had any problems for the past 2 months. Maybe this will work for you also.

Let me know if that helps.

[mmartin]

You may also want to pull your carb off and clean it out. If you didnt drain the gas from the bowl the float may be stuck or jets clogged, could be a few problems associated with that.

[schootar]

Sparkplug.

It's been my experience that the sparkplugs in 400s need to be replaced from time to time. I always have at least a few spares with me. I've pulled plugs before when I couldn't get the EX to fire, they look fine but don't work, put in a new one and it will fire right up.

I've recently removed my choke and put in a 42 pilot and haven't had any starting problems since other than the fact EXs are cold blooded. I would look into putting a 42 pilot in yours, it will help with the hard starting.

[sprtrx300ex]

New spark plug.

Try turning your fuel on, pump the gas once or twice then hit the starter, you might have to hold the throttle open a tad too.


If this doesnt work, then turn the choke to half and try again.

[ZQ8Dude]

seems like a 04 thing. mine did this just last week!

ive got like 5-6 hours tops. easily 50 miles on it and the motor is fairly broke in.

anyways we went out to run it and it would just crank, took like 10 minutes to get it going right. after running the piss out of it and the track, it seemed alright, actually better then the previous times. we loaded it up, drove home, and i washed it i the driveway. then it started up right away and idled perfectly(last ride i had trouble with it starting after a wash)

[250rAL]

I had similar problems with my son's Blaster. It would run fine for several rides then the next ride it would start, run a few seconds then quit. Even pull starting wouldn't get it running. Switched the plug and it would start right up. Afterwards, I cleaned the old plug and put it back in and it ran fine. Couple rides later, the same thing. Finally figured out the plug was intermittantly faulty.

[Yorrick5]

Thanks guys! I knew I could count on the gear heads here.

The concensus seems to be spark plug, so I'll give that a shot tomorrow. I probably should have tried that after I replaced the fuel, but I figured with only 10 hours on it (and since it seemed to spark pretty well when it was out), it *couldn't* be the plug...others who know waaay more than I do have corrected my assumption. Thanks!

I'll post the results after a plug replacement (or after I haul it down to the shop, which is my last, last resort).

[sean94z]

Have you ever stood it on the bar, I did and oil got in the carb and clogged the jet. I had to drain the bowl everytime I went to start it cuz it would never start. Just a thought.

[Yorrick5]

Heh.

It turned out to be the plug. I'm a little embarassed for not having replaced it first thing, but I figured all was well.

The one (crap) Honda dealer down here didn't have the plug I needed, so he gave me a nine as opposed to an eight but with a colder plug, it fired right up. Runs rough, but at least it runs. Now I just have to wait at least three weeks ( :mad: ) for the dealer to get the correct plugs in and I'll be rockin' and rollin'.

Thanks again, guys. You saved me some money and saved me from having to push the 400 up the ramps into my truck. :)

[rubiowner01]

Try a local autoparts store. They should have the correct plug. If not you could even order them online quicker than waiting on your dealer...

[notfastenuf4me]

sounds like ur suppose to run a d8ea and he gave u a d9ea i found runnin a hotter plug in my 250x made it runn better and start easier but i also had a full exhaust jetting and high comp piston

[mmartin]

You may still want to run the 42 pilot. It makes a world of difference.