G'day all,
The CB750 F2 has under gone some modifications. Port polish head, 900cc kit and now a hot street/strip cam (Ivan Tighe 369 cam in OZ). It has moderate mid range and is aimed at top end performance. Hit 6500rpm and it takes off like a rocket and with 48 tooth rear previously would wheel stand with a slight pull back on the bars. Stock airbox has the bottom scoop removed to allow more air in. Stock F2 carbs with needle clip position 1 rich so 2nd from the bottom and 120 mains. Top end works well with 120 mains. The problem I face now is if I'm one gear high about 4-5000 rpm and go almost WOT quickly, it tends to stutter or break down. Back off throttle and wind on slower and then hit the performance curv and magic 6500 rpm no worries then. Keep WOT from 4-5000 rpm until hit 6500, it will pick up and take off. Not sure if I need to go richer for mid throttle range or not.
I haven't had much to do with top end performance cams as the last one I has was more mid range and not much top end and carb setting was needle 1 rich and 120 mains. The difference between the cams is I get and extra 20-25 kmh (32-40 mph) out of the top end performance cam over the same distance from a standing start say 1/4 mile, I actually haven't measured it just more interested in the needle on tacho/speedo and the trees as they go by. Carb have been sinked.
Open to suggestions. Cheers.
(PS. I'm trying to put a set of 29mm smoothbores on but need the honda bracket/rack that the carbs fit onto to get them on the bike)
