sputturing at high rpms

[bluebullie]

just the other day i was riding pretty hard on the track and all of the sudden my quad starts sputturing when it gets high in rpm... loaded it up went home cleaned it and put new spark plug in it and its still doin it. its got a rev limit kit and jet kit..... any ideas why this is happening.... this is the first time it started doin this. kits have been installed for a while

[whiteflash]

your jetting might be rich..

[Joe400ex]

mine was doing the same thing the other day and i changed the plug and it did it again but i rode it really hard down the block and it stoped its weird what gas is in there and how old is it:)

[bluebullie]

93 octane , got me wondering if water got inside while i was cleaning it?

[roostin_dale]

How is it sputtering? like a bogging, starved of fuel or what?

[brian-250]

does it run rought at idel? and die out when you rev it up? if it does that your main jet fell out.;)

[bluebullie]

it runs perfect at idle it just acts like its bogging out and backfiring at high rpm

[roostin_dale]

at high RPM? Hmm, im not a jetting expert but i do know a little about it....try bumping up your main jet...

[crazyatvn]

high rpm's is the main jet. If it ran good before the claen the main jet. If it did not go bigger.

[igmif]

Did you have a few hard landings? If you quad was running great, then suddenly started craping out on ya, then you might have shaken up something up in your carb. Make sure you didn't crack your floats, and check and make sure you don't have an air leak around the rubber intake boots. Hard hits can knock that carb right off. If this turn out to be your prob, you should try safety wiring the carb on.

[TC426EX]

Check that the airbox boot is connected to the carb. I ran into this problem a couple times and it behaved something like yours. When you remove the lid from the airbox it loses some structual strength making it easier to pull off the carb from landings and such. If thats not the problem I would go up a size or 2 on the main jet. Either way it looks like youre gonna have to do some testing and fiddling to tune the bike in

[cals400ex]

i am going to be in the minority and say go smaller on the mainjet.

[hatch]

thanks guys, ill try all of your suggestions until i get it right.... keepem comin guys

[Toadz400]

Originally posted by cals400ex
i am going to be in the minority and say go smaller on the mainjet.

I was going to say the same thing. My Banshee is doing the same thing right now because of the rich jetting from winter. It's most likely running rich in the main jet, the sputtering is from too much fuel.

check plug gap, mixture setting, clean/rebuild carb, valve adjustment, anything can be your problem because everything is so critical, but it seems like a rich mixture, check if your chike is full open

[2004exrider]

check that your main isnt loose or hasnt fallen out, if not try smaler jet and check your plug to see that its not running lean.