I bought this Hawk in November '11 and found it came with a BMC race filter installed. It ran fine with no difugalties at all and also mounted was a Jardine RT-1 set, loud and baffle free. Made good power and got 40mpg or more with my cruiser style of riding. It ran the same with stock filter and stock mufflers installed, go figure, but got 6mpg less. I just got into the carbs and found a 180 jet in front and 178 in rear and 45s slo's and stock needles with .030 shims. Also found aftermarket springs 5.25 inches long. Anyone know who makes those? Also found leaky float valves and replaced those. You know they're leaking when you take the gas lines off the tank and no gas runs out of them. Backs of the intakes also coked up and wet. I now have 178's front and rear, 45s, tps at 500 ohms, long stack in front too, pair and carb heater hoses ditched. Synced the carbs and idles perfect now with no clunks, farts or whatever you want to call it and best of all doesn't even hint at stalling in any situation. I blame that on the pair system. Think about it---exhaust and intakes both open at tdc forcing mixture into the header and an injection of o2 via the pair. Bam, detonation that at idle stops crank rotation. I did not pull the float vent hoses out of their nest and point them down. Took it for a spin yesterday and today and got 45 mpg with stock pipes and that's up from 35mpg with stock pipes, flawless running idle on up with stock filter still in place. Elevation here is 200' and I'll post a vid of it idling at 500 rpm if you want. I'm amazed.