08 yz250f bogging issues

MicMcDude375
Edited Date/Time 8/7/2015 4:56pm
The bike starts up fine but whenever the throttle is applied, the bike chokes and dies. I pulled the spark plug and it looked to be running pretty lean. I figure that there is a problem with the air screw or accelerator pump based on where it dies in throttle position and what I have read on the internet. Any one have this problem or know the exact solution? Thanks for the help.
|
xnationalwrench 8/6/2015 2:39pm
8/6/2015 2:39pm
1st Place I would check is the pilot/low speed jet, for blockage and you can't really spray it while it is in the carb you need to remove it and make sure you can see thru the bore cleanly and clearly..
MicMcDude375 8/6/2015 3:30pm
8/6/2015 3:30pm
So I took the carb apart and checked all of the jets and made sure they were all clear. Then I reassembled it with the air screw out another 1/2 turn and put a new spark plug in it and that seemed to help a little. I noticed that if I turned the idle speed up, it would not bog when I snapped the throttle open, which makes me wonder how do I know if I have it at the correct idle speed?
Paw Paw 271
Profile picture for user Paw Paw 271
Posts
3632
Joined
4/3/2013
Location
Benton, LA, USA
Paw Paw 271 8/6/2015 4:00pm
8/6/2015 4:00pm Edited Date/Time 8/6/2015 4:00pm
Your bike does not have an "air screw". It has a fuel screw under the carb. It should be set at about 2 turns out from fully closed. Turn it CCW to richen the fuel mix and turn it CW to lean it out.
At 1/2 turn you are very , very lean.
Idle should be at about 1500-1800 rpm.

Paw Paw
MicMcDude375 8/6/2015 4:13pm
8/6/2015 4:13pm
Sorry, the fuel screw is what I was talking about. I turned that to about 3 turns out and it helped a little. I know that the idle speed is supposed to be between 1900-2100 rpm but I am not sure how to check that since I do not have a tachometer. I am also going to recheck the accelerator pump timing since I am a little suspicious that it might not be correct.

The Shop

See All »
Paw Paw 271
Profile picture for user Paw Paw 271
Posts
3632
Joined
4/3/2013
Location
Benton, LA, USA
Paw Paw 271 8/6/2015 4:53pm
8/6/2015 4:53pm
You can pick up a vibration style Tachometer at a lawn mower parts house. It is how they set the correct RPM on small engines and it works well on small 4 strokes as well. It's only a few dollars.
Fuel pump setting and timing is a big thing on these bikes.

Paw Paw
MicMcDude375 8/7/2015 1:52pm
8/7/2015 1:52pm
Thanks for the help guys. As of right now I have put it all back together and it seems to be running much better, expect gas seems to be leaking out of the float bowl and accelerator pump. So I've ordered up a new set of seals and hopefully that should be the last thing I need to do.
Paw Paw 271
Profile picture for user Paw Paw 271
Posts
3632
Joined
4/3/2013
Location
Benton, LA, USA
Paw Paw 271 8/7/2015 4:56pm
8/7/2015 4:56pm
Be sure to reset your float height.

Paw Paw

Post a reply to: 08 yz250f bogging issues