four strokeing at mid throttle

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
hey yal,let me first tell about the bike.gt 80 engine,reed valves,transfers port matched,ported piston,exaust and intake port matched,1979 suziki rm 60 chamber with fred c header.sill has stock jets in carb. all on a shwinn blackwell frame.the bike will do 40 + ,and gets there pretty quick.o yea,about 12 13 hundred hard miles on it.heres my problem,it has a hesatation around mid throttle.ive reset the needle more times than i have fingers,both up and down,the fuel mixture screw is set at about 3/4 turn out from bottom.thats where it runs best.any other fuel mix no good.the hesatation is worse when its cold.but almost clears up when warmed up. i just posted some pics on the high proformance thread . thanks
 

Greg58

Well-Known Member
May 1, 2011
4,187
1,064
113
62
Newnan,Georgia U.S.A.
Mike if it is running rich the spark plug should be dark color, it should be light brown on the porcelain. Have you made a test run without the air cleaner? If it runs better you need a smaller jet.