07 wr450 running rough at 1/4 throttle

I recently purchased an 07 wr450. When i got it the previous owner removed the trottle stop and rejetted. I just opened up the airbox.When i'm at 1/4 throttle the bike coughs and sputters. Is this because the A.I.S is still attached.

I have the same problem with my 06 450 cruising at low speeds quarter throttle and it splutters. I have recently purchased a J.D Jet kit and the problem seems to have gotten worse, I have tried leaning and richening the needle and going up and down in main jet size and it doesn't effect it at all in this range... any help would be much appreciated.

do you still have your A.I.S attached also? I have also tried my jetting

:lol: Welcome to the world of WR stutter!

This is most likely from the TPS (throttle position sensor), you can do a search for a wealth of info. I just removed my fuel tank and unplugged the grey connector on the left side. You can only hope of minimizing, you're lucky to eliminate it.

I don't notice it much on mine anymore, was horrified! when I first bought it (07). Also, make sure the grey wire mod is done (search) don't clip the wire just remove the pin on the connector.

Probably doesn't have anything to do with the A.I.S. These are great reliable bikes, they just have some quirks (like the chain rub on the frame!:banana:).

Edited by desertlover

This partly fixed the problem 4 me, its better but somethings still not right. I think i might be lean on my pilot jet because to stop decel back fires i have to wind out the fuel mixture screw a fair way. Oh well ill keep tinkering with it, its deffinately a learning process 4 me!

My 07 doesn't sputter at all, I think your jetting is just off. When I first bought it there was a popping on decel and I believe it was the ais system. I have that removed and rejetted and I have no issues. Good luck you will love the bike

My 07 doesn't sputter at all, I think your jetting is just off. When I first bought it there was a popping on decel and I believe it was the ais system. I have that removed and rejetted and I have no issues. Good luck you will love the bike

Mine runs fine too after a good re-jet and fine tune. I do remember having that issue a long time ago, tried disconnecting the TPS but it didn't help. Turned out to be the wrong pilot jet size and slightly off fuel screw adjustment.

I took the pilot jet out and gave it a clean, took off the o-ring mod from throttle cable cuz that diddnt feel right and richened fuel mixture. now its running like a dream. I bought a bigger pilot jet on ebay aswell its got a 48 in at the moment and i got a 50 and 52 so then i can wind in the mixture screw a bit. Thanks for everyones help.

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