Hi there!
Indeed, your bike should be reaching for 80-90mph or even the ton. I know because I've reached it on the same bike.
The maintenance you did is great, as you've addressed the air flow and the all important brakes.
However, I think you should dig deeper on the fuel and sparks. You can remove the carbs and check if the Pistons are moving freely. They are vacuum actuated so if they stick for whatever reason you won't get enough fuel to make her run hard on the top end.
Change the spark plugs, as they get worn. Once you do that, run with her for a while. Then give her a whack in 1st gear and cut the motor on the top rpm (with your hand on the clutch). Check the spark plugs. They should be tan, not white nor smokey black. The electrode shows the top end of the rpms, while the base shows the bottom end. If white, you are lean. Black, you are rich in the mix.
Also check the petcock. Remove the gas from the tank and change the petcock for a new one, while checking for rust. This is very important, and often overlooked. The petcock should provide enough flow to keep the bowls full when on wide open throttle. Do not use any fuel line filter, as they never have enough flow, and the petcock screen should suffice.
Feel free to chime in if you have any problems.
Indeed, your bike should be reaching for 80-90mph or even the ton. I know because I've reached it on the same bike.
The maintenance you did is great, as you've addressed the air flow and the all important brakes.
However, I think you should dig deeper on the fuel and sparks. You can remove the carbs and check if the Pistons are moving freely. They are vacuum actuated so if they stick for whatever reason you won't get enough fuel to make her run hard on the top end.
Change the spark plugs, as they get worn. Once you do that, run with her for a while. Then give her a whack in 1st gear and cut the motor on the top rpm (with your hand on the clutch). Check the spark plugs. They should be tan, not white nor smokey black. The electrode shows the top end of the rpms, while the base shows the bottom end. If white, you are lean. Black, you are rich in the mix.
Also check the petcock. Remove the gas from the tank and change the petcock for a new one, while checking for rust. This is very important, and often overlooked. The petcock should provide enough flow to keep the bowls full when on wide open throttle. Do not use any fuel line filter, as they never have enough flow, and the petcock screen should suffice.
Feel free to chime in if you have any problems.
