400ex suddenly sluggish, poor throttle response

[jfisher]

I've got an 02 400ex and have ridden it several times this year with no issues. It's fairly quick and has always ran very strong.

This past saturday, I went riding at a buddies dads' house. Out of nowhere the quad doesn't want to rev and is very sluggish when reving the quad with it sitting there running in neutral. It starts and runs fine, but when you give it has, it hesitates and doesn't rev nearly as quickly as it used to.

The quad still runs and rides ok but when getting on it, it won't even rev all the way out and struggles to climb in RPM at all.

Any ideas on what I can check for?

[01boneless]

sounds like the needle on the carb fell off or the clip poped of. mine done it once. clean the carb while your at it.

[jfisher]

Thanks sir, I'll give that a shot!

[Pipeless416]

i always tell people to check the obvious first.. obvious here being the choke. i can't tell you how many times i accidentally flipped the choke lever when i had a stock carb, and then i wondered why it felt like my rev limiter was set at like 2000 rpms haha.

[jfisher]

Originally posted by Pipeless416
i always tell people to check the obvious first.. obvious here being the choke. i can't tell you how many times i accidentally flipped the choke lever when i had a stock carb, and then i wondered why it felt like my rev limiter was set at like 2000 rpms haha.

I did make sure to check that lol :)

You are right though, one thing I've learned is to check the easy things.

[JOHNDOE83]

Originally posted by 01boneless
sounds like the needle on the carb fell off or the clip poped of. mine done it once. clean the carb while your at it.

Mine to!

I hit a jump at a mx track and it suddenly happend, took it apart and the needle clip fell off.

[HondaPohl]

Go through the carb.

[jfisher]

Thanks guys!

[Drfat400ex]

I agree with these guys to look through the carb, but just in case check your spark plug, save you time if that's whats wrong.

[Zeb400EX]

check your boot that connects the carb to the airbox. mine's came off after a hard landing and after a tumble down a hill. the carb was sucking in so much air that when i would give it full throttle it would just fall on its face. also to check for other air leaks you can take some carb cleaner and spray around the carb connections and the top and the bowl. watch to see if it the idle changes when the cleaner is sprayed in those spots.

spray around the head gasket too. it could have blown, but you would probably hear a sort of hissing sound. couldn't hurt to check though.