Running lean

W

WEEDHOPPER

Member
i have a ld90 with a fred head. My bike was running great and then my cdi went out, i have a catnip cdi,coil and mag but am having major power loss. Going from a double plug set up to the single plug catnip( same head just leaving the other plug unhooked) i decided maybe my stoke plug wasnt strong enough so got a ngk plug for it. Ganed alil improvment but wws still under powered as well as harder to start so after about 2 miles i did a plug chop and my electrode is white. But im not sure why im now running so lean when nothing else has changed.
is it because of the single plug
 
It's possible that a small bit of dirt is clogging the petcock or the carburetor jet causing the engine to run lean... (that's why the plug is white).

Clean them both & report back. :)
 
How is the idle of the engine ?

you haven't had to back the idle screw out any to bring down idle rpms ?

Either starving for fuel as VMB said or air leak.

CDI, COiL, Spark Plug etc... will have absolutely nothing to do with whether an engine runs lean since that condition is caused by the Fuel air ratio being out of whack.

Pull the fuel line off carb and open petcock to make sure you have good steady stream of gasoline to carb.

if you do have good fuel supply to the carb., then you have an air leak or the main jet in your carb. is to small.

If the idle rpms have ever increased on it's own. that is s clear sign of an air leak at a seal or gasket.
 
Sorry it took so long to post an update but here goes.
Evidently when I torqed my head down (not having a torque wrench) I didn't get them tightened evenly enough causing my head to warp. Also one of my acorn nuts had stripped enough to not stay tight enough on one side. I rethreaded and it's now running better and have a new aftermarket head on the way.
Thanks for all the help guys
 
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