Honda-SOHC

Thanks for the tips,but all seals,o-rings,inlet rubbers are new on my bike.I'm gonna do some simple test now by blocking half the airinlet on the airbox,see how it response.

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?