Engine dies when abruptly applying throttle | GTAMotorcycle.com

Engine dies when abruptly applying throttle

O

Owen

Well-known member
Just got a Yamaha 2008 WR250x.

When I abruptly apply the throttle, the engine dies. If I slowly roll on, it revs up as normal. If you abruptly apply the throttle with the revs already a bit higher than idle, then it hesitates but does not die.

The previous user has a FMF power programmer with a FMF Q4 full system. I thought I might have changed the settings by accident and caused this, so I disconnected the programmer. It's still doing it.

I can fix things if I know what the problem is...but I have no idea what's causing this.
The air filter is clean. I also replaced the spark plug too. It was all sooty and a matte black.

Any idea where to start?

Thanks!...trying to get this going for some ice racing this winter!!!
 
Not specific to the WR250 but I would start by making sure the TPS is working correctly
 
With engine cold or up to operating temp?

Stock exhaust system available? You can also ask the previous owner ... he knows the bike and what exactly he has done to it.
 
its probably a lean condition, its cold out man. quick test, tape 90% of the filter up. or if it has a programmer, add 25% fuel
 
After looking at some sparkplug charts, the old plug might be indicating it's running lean.

mxs said:
With engine cold or up to operating temp?

Stock exhaust system available? You can also ask the previous owner ... he knows the bike and what exactly he has done to it.
Click to expand...

At operating temp. I do have the stock exhaust as well. Easy enough to swamp that on for a shot.
 
The air box has been drilled out (regular mod with this bike). But most of the wholes are taped up. I could also tape up the filter too.
 
You must log in or register to reply here.

Back
Top Bottom