I'm new on this forum,living in Belgium so my english will be spitting.The past 6 monts i've restord a CB550K 1977..engine,frame the hole storie,is not complete yet (still needs to be painted,seat,spokes)but I already riding the thing.Bike came to me with 4 into 1 Marshall,end still using this exhaust.Ignition,carbs all rebuild,stock airbox..everything is stock.Bikes is running not so smooth,engine feels lazy in low rpm's.I think the problem is the exhaust... mixture to lean with 4 into 1.I did some research in old honda manuels,so a 77' CB550F came with stock 4 into 1 pipes,jets 98 but diffrent carbs to (bigger venturi).My bike has Keihin's PD46C carbs with stock jets 90,so i think i've have to put in also 98 jets.Anybody some experience with this...a good jetting tip with 4 into 1 Marshall.Ore will 98 jets be to big for my cabs?