Hi Guys,
I rebuilt my sons 1999 YZ125 top and bottom. Brand New cylinder, piston, crank, crank bearings and seals. Rebuilt the carb with stock jetting. Reeds and Pipe are stock. The bike runs a little ragged and wihen topping it out in 4th down a straightaway it starts to break down and run a little ragged like the choke was pulled out or something. It runs pretty good down low and mid range. The plug color is tan after two tanks of gas thru it, but I have to run a plug from my KX250 in it to run. The stock BR9 plugs fouls out very quickly. I'm thinking I have weak spark but cannot afford to start swapping parts until I get lucky. Any advice?
BTW - filter is clean and oiled properly, exhaust is not plugged in any way.
I rebuilt my sons 1999 YZ125 top and bottom. Brand New cylinder, piston, crank, crank bearings and seals. Rebuilt the carb with stock jetting. Reeds and Pipe are stock. The bike runs a little ragged and wihen topping it out in 4th down a straightaway it starts to break down and run a little ragged like the choke was pulled out or something. It runs pretty good down low and mid range. The plug color is tan after two tanks of gas thru it, but I have to run a plug from my KX250 in it to run. The stock BR9 plugs fouls out very quickly. I'm thinking I have weak spark but cannot afford to start swapping parts until I get lucky. Any advice?
BTW - filter is clean and oiled properly, exhaust is not plugged in any way.