Surging at high speed

[Twobond]

Hey all,
‘79 750k here.
Just rebuilt carbs and set valves and while riding at high speed, 70 mph or so.
The engine will surge about 2 miles per hour.
What could possibly be the cause.
Walter/Houston

 

[Oscar Meyer]

The engine will surge about 2 miles per hour.

Are you saying it surges while the bike is rolling at 2 miles per hour? If it is doing it at 70 mph then it is probably running lean. What do the plugs look like? What jet sizes are you running? What carb kits did you use?

 

[Twobond]

The bike is going 7O and surges 2miles per hours, new plugs. I will adjust for lean.

 

[Oscar Meyer]

The bike is going 7O and surges 2miles per hours, new plugs. I will adjust for lean.

How do the plugs look? Do they look like it is running lean? I don't understand what you mean by "surges 2 miles per hours". How do you plan to "adjust for lean"?