Kdx 250 sputters at full throttle 1-4th!!

[Spetty]

It's me again. I got on my bike to ride today and noticed my bike sputtering at wide open throttle from 1st gear through fourth gear. I haven't done anything to the bike differently to make it start doing this. I tried changing the plug and making sure my air filter is clean. Didn't help anything. Any advise is greatly appreciated.
Thanks,
Zane

[royadams]

Have you changed any jetting yet. The 250 is known to be extremely rich from factory.

[Spetty]

No I haven't. it just seems weird that it ran flawlessly until today.

[Spetty]

So is the float the general consciences ?

[Spetty]

Bump

[royadams]

Does your bike spooge alot, mine did and made a mess of everything. If so clean your silencer and rejett. You can check your float and kips for function. My bet is jetting and a pluged silencer.

[Spetty]

How do you check kips?

[scheckaet]

have u tried cleaning your carb and petcock filter?

[Spetty]

No I haven't tried that. I just couldn't believe it happened over night but I guess that's possible.

[royadams]

You have got to start some where. Everything we mention does not make since to you. Check compression, clean carb and check jetting. clean silencer, clean air filter. To check the power valve remove the cover and start it rev the engine and see if it moves. Its hard to say without hearing or riding if its a rich or lean condition. If lean it will surge and slow surge and slow like you keep chopping the throttle. If rich it will be more of a shuttering action kind of like a misfire. I would strongly suggest you check your jetting the 250 are know to be way way rich. I run 32 158 I believe. Br7es plug one size leaner slide and two sizes leaner needle. What did your plug look like how much spooge we need more info.how does it run down low and in the mid.

[Spetty]

The bike idles very low and does not respond when I turn the idle screw. But when I first start it the bike idles very high. The throttle has a little but of lag when you barely crack it but after that it runs great up until wide open throttle. Airfilter is brand new and new plug.

[royadams]

If its idling low with no response to air screw its rich. You need to pull the carb and check everything out . Maybe the jet fell out. maybe the top end is wore out. Have you checked the compression. Have you pulled the silencer off and ran it with out it.

[Flanker]

+1 on repacking muffler mine lost power at the begining of a ride 20 mile later it was bogging like crazy at full throttle its only 10 buck at most half hour of work makes a huge difference of it has not been done in a while, it does seem to brake down over night. A large pilot jet will give you a low idle a temporary fix is to tune the air screw as it says in the jetting guide mine is nearly 5 turns out to have the idle be normal however this not a fix bike will still not run very well in till you jet it properly go here http://www.kdxrider.net/forums/viewtopi ... 105&t=1156

[Spetty]

The bike was "supposedly" rebuilt right before I bought it. Top and bottom end. He had pics. Who knows if it was the same engine. But I guess I'll start by taking off the carb? I've never tested the compression. Been too scared honestly.

[6 Riders]

Rebuilding the motor often requires re-jetting. Might want to look at reeds and repacking the pipe (if needed) before jetting.

[Spetty]

Ok il try that. Although I'm sure he didn't replate the cylinder probably..