Dream CA77 305cc bogging down

[Garth]

Hi folks. I'm new to this forum. I own a 1964 Honda Dream CA77 305cc which I have just recently started to drive. I've noticed that when up to highway speed the bike seems to "bog down" when I reach even a small hill. I've just had the carburetor rebuilt by a good mechanic and it starts and runs great. Just the problem with hills. I'm going to do a compression test first. If it is good does anyone have suggestions, step by step, of how I proceed from there? No blue smoke or excessive oil consumption. No knocks, shifts fine and runs great on the flat... Any suggestions would be very much appreciated!

[sky.fred]

You have to realise that this engine only delivers its maximum torque and power at high engine speed and the gearbox is very badly designed, with a huge gap between 3rd and 4th.
I can't climb a hill with my C72 in 4th gear if the engine speed isn't high, and most of the time I shift back to 3rd gear.
What's more, the 305 (and the 250) require very precise adjustment of the break points. Adjustment with a strobe light is necessary because if the setting isn't perfect, it's even worse.

[Muddy]

I agree with sky.fred, they are not a powerful motor and the gearing leaves a little to be desired. Make sure your expectations are not too high in relation to engine output power and that you don't wreck a good-running motor trying to over-power it. A leak-down test will tell you a little more than a compression test eg if there are piston ring or valve issues. As sky.fred said, also check the points, ignition timing and spark plugs.

Let us know what you find.

Good luck!