400ex Cutting Out In A Wheelie

[itsallgood]

Here recently, well it started about a month ago, my 400ex started cutting out when trying to ride a wheelie. When it started I didn't think much of it, I ended up buying a house and have been moving, etc. so last week I got it out and went riding. Same stuff, it's cutting out when I get into a wheelie. Just dies when the front's up in the air, basically I could keep the throttle WFO and it never flip me (hopefully), b/c it would hit a certian incline and cut out which lowers me back down. Does anyone know what this could be? I haven't made any modifications to the quad since I bought it about 3 months ago. I'm not sure on the jetting right now since I haven't had it apart. Any help would be appreciated. I also already checked the overflow tubes for blockage. It is also a stock carb, wb r-4 slipon, airbox-lid removed, (jetting ??).

[Aceman]

Make sure there is plenty of gas in the tank. If that's alright tear the carb apart, clean it, and check the float height.

[Jingle 11]

the older 400's had a bad intake boot. Mine was cutting out do to the extra air cuz the boot cracks. but if u havent checked it u might wanna seeing that its winter and it mighta cracked. its the boot that runs from the carb to the head.

[nosliw]

maybe because the thing wasnt designed to operate at a 45degree angle? :D


just a thought

[Jingle 11]

lmao does it do it going up hills?

[itsallgood]

It is a 2002 so it's fairly new. It started doing this when it was like 60+ degree's outside so I don't think it's the temp. change that's causing it. It was full of gas the last time I rode it, already checked that. I know it wasn't designed to work at a 45 degree angle, but how many other 400's cut out while riding a wheelie? I haven't noticed this problem while trail riding, up and down hills yet. My friend that I ride with doesn't have any problem at all with his.

[mojoe2878]

i would check the float height like someone else on here said. if its set too low it may not be letting enough gas into the carb. bowl and when you wheelie and all the gas goes to the back of the bowl, the main jet wont have any gas around it to pull through and feed the engine. so check to see if the float height is set high enough.

[RIDER11X]

When working properly, the 400ex shouldn't cut out riding a wheelie. I go well over 100yards with no problems cutting out. Maybe when it is on the grab bar it might cut out, but that is about it.:eek: Check the floats, and for dirt in the bowl. If the quad had old gas in it, varnish may also be a culprit, so clean it out real good while you are in there.:cool:

[cals400ex]

check the jettting and let us know what is in there. what year is the bike???

[SixthFloorFreak]

http://www.exriders.com/vbb/showthread.php?s=&threadid=98640

worth a shot...though its probably not the case

[Aceman]

Originally posted by itsallgood
It is a 2002 ;)

[itsallgood]

Okay, I'll check the float level for sure. What is the correct float height? Also, how do you adjust the float level in a stock carb, aren't they all plastic? Do you just heat them and put them where they need to be? Hopefully I'll be able to check all these possible solutions this weekend, if I get my house where I can sleep on the bed instead of the couch before then.

[honda_runner]

yeah the same thing happens to my friends quad, he has '04 426ex, i hope he goes on here to talk about it.

my quad can do a wheelie at 80 degree, i have no problems

[cals400ex]

sorry about that. i skipped right over the year. i would make sure all hoses on the carb are clean and not full of debris. also, take the carb apart and clean it along with all of the jets really well. i don't believe the float can be adjusted on a 400ex.

[crandles]

Mine did the same thing. I found it was to rich on the main. I put a smaller main in and it fixed it.

[itsallgood]

I've been really busy latley and haven't had time to reply to this message, but I did get it fixed...and then spent 3 hours of riding nothing but wheelies w/o any problems. If I would have looked at it before I posted there would have been no need for this post. Anyway, the throat that goes from the airbox to the carb was completly off. So I cured it and I'm finally happy with my ex...

Thanks for all the replies, lots of information shared on this board.