My engine stalls after a jump, any suggestions?

[450rGuy78]

First of all, I'm new here, but I've checked out this site quite a few times. It seems to be a pretty good site. Now...here's my prob. I was at a local MX track on my 450r this past weeekend, and after about 8 to 10 laps I started having problems with the engine cutting out. It did it a few very brief times in the rythm sections, but nothing major. The worst place was a small tabletop right before a double. It would cut out after I hit the ground while I was getting up speed to hit the double. The third time it done it, it completly died right as I started up the face of the double. Needless to say, I came up short, and badly nose down. Now have some decent road rash, a sore back, and a slightly banged up r. I was wondering if on the tabletop, the float was sticking closed and not opening back. Then I was simply draining the float bowl by the time I got to the double. Could this be the problem? If anyone thinks I might be right , how could I fix this? If anyone has had this problem or knows what might be happening I would greatly appreciate some advice. I've just bought the quad about 2 months ago, and I'm trying to get into racing, and I really, really don't want to come up short on a 40' double in the middle of a race in a couple of weeks.

Thanks

[Florida400EX]

My 400ex is also doing the same thing so I'd also like to know, cause yes, it's dangerous.

[Quadzilla]

Mine used to do that also and one day it went away by itself. Never knew why or what caused it. I was thinking at the time that it might be a stuck float in the carb or something.

[pikey21]

should have got a 300ex and saved some money i have know problems on the track:blah: :blah:

[CEET400ex]

then he would be last on the track lol...j/k dude:devil: :huh

[quadmx7]

my 400ex used to do it, it cut out on me over a 85ft step up triple but wasnt too bad and would cut out before some other doubles. my new air box came in the next day with no lid and never had any trouble after that donno how the air box fiexed it or if that had anything to do with it but never had any more trouble

[TCracin440ex]

might be trash in the gas tank and when hit the jump the trash goes into the hole for the gas line

[Chanman420q]

check your air box, my air box was completely busted and i had the same problem

[450rGuy78]

Thanks for the replies guys. I'll check out everything you all have mentioned in the next few days. I hope the "it just went away" theory works for me though. It really makes me leery of hitting that double though.....never know when it might come back.

By the way....if I'd bought a 300, this never would have happened, because it would be almost impossible to clear that double. I would have never even thought of trying it. It takes 3rd revved out, then half of fourth to just barely get the back tired over the lip on the landing. But thanks for the post anyway.

Later

[speedy400]

I didnt read any of the replys but check your parking break thing, I had a big problem with that.-darren

[CEET400ex]

My friend has a Beartracker Ute and it would cut out and die. It ended up bring the gas cap vent hose being all twisted up...so if it is untwist it. Or maybe theres something inside it....take a compressed air nozzel and stick it in the end of the hose that goes into the gas cap and spray some air through there a few times. Just a thought though....

[450rGuy78]

I've been thinking, does the 450r have any kind of low oil shutdown? If so then maybe the oil was getting off the sensor on that jump and that was causing the shutdown. But if that's the case, why did it do it after I had landed and was heading for the next jump? I'm also curious of how the parking brake mechanism would cause that? I went out and run 10 laps on my practice woods course and didn't have a single problem the whole time. So I'm leaning towards the float sticking because of the jump, then I was draining the float bowl on the way to the double.

Thanks for the replies.

By the way, the gas vent hose was the first thing I checked and everything was fine.