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View Full Version : Still Bogging???



mike84bigred
12-26-2009, 06:23 PM
For the guys that haven't read any of my post recently, I have an 85 250SX, with a Cobra exhaust system, Web-Cam cam, Web-Cam valve springs, and jetted carb.. The machine runs great except if you really pound the throttle, to do wheelies, etc.. Even when i'm in neutral, if I go from idle, to half throttle quickly, it will totally die out. Still seems to be running a bit rich too,carbon on the plug. Any ideas what I should do next?

Here's the things I hope it may be. Petcock not producing enough fuel, octane level of fuel to low (only using 87), spark plug to cold. Thats all I got. Timing is dead on, and the valve clearance is .004 which the cam requires.

harryredtrike
12-26-2009, 06:30 PM
running air filter?try taking it off and see how it runs.double check all your carb settings.to see if fuel has good flow pull the line off the carb and turn on.good flow means good to go.

Russell 350X
12-26-2009, 07:07 PM
Try rejetting your carb. If its running a bit rich try a size or two smaller main jet. Also, try 91 or 93 octane. All I run in my toys is 93 from Mobil or Sunoco.

mike84bigred
12-28-2009, 10:03 AM
I ordered a brand new petcock. I'll see what that does, but if not isen't it, I don't know. Had it at the shop, and they made some adjustments to the carb.. I ran it once, and it seemed to be good, but when I brought it home, I changed out the petcock because the one on there was leaking. I'll change out the filter as well.

oscarmayer
12-28-2009, 10:30 AM
you may also need to take the carb appart and clean it. (at least the bowl area). but yes change the filter, and clean the carb and you should be good.

if it's running rich. the carb could be plain worn out and just need a basic rebuild.the jets needle and seats all wear over time. a rebuild kit gives you stock fresh new sized jetting and parts so it should run much better once rebuilt.

mike84bigred
12-28-2009, 01:21 PM
Been rebuilt recently.

daniel_250r
12-28-2009, 01:47 PM
take off the air box lid, my 200es big red has a cobra exhaust, and a new china carb and i had to take off the air box lid for it to run spot on

mike84bigred
12-28-2009, 03:04 PM
take off the air box lid, my 200es big red has a cobra exhaust, and a new china carb and i had to take off the air box lid for it to run spot on

Did your bog at low end like mine?

daniel_250r
12-28-2009, 07:26 PM
it was every where wouldnt idle corectly either just take it off and boot around a bit

oscarmayer
12-28-2009, 07:38 PM
that emans if you took the lid off and it runs right, then it's a filter issue. something is plugged getting air to the system

mike84bigred
12-29-2009, 06:07 PM
Removed air box lid and no more bog??