Topic: Carb adjustment

[Dave B]

So CB750FO now almost complete 
Engine and carbs rebuilt.
New points, leads,plugs and coils.
starts on the touch of the button.
runs faultlessly up to about 40mph.
However when i give it more throttle it does not increase speed and gradually dies down to low revs
then is fine again.
Plugs are loverly and clean and ticks over effortlessly.
Any ideas please.
Cheers,
Dave.

[fizzlebottom]

Rather than run in gear, can you find out if it does the same thing in neutral and won't rev through the whole RPM range? Tire speed isn't really telling.

You mentioned replacing a lot of items, but nothing about adjustments. Timing, valve clearances, carb sync. Confirm you took care of those and someone much more knowledgeable than myself will hopefully chime in.

[Dave B]

All settings are per manual and it revs perfectly in neutral.

[wildtapholer]

My problems were very similar, new needle valves made the float heights wrong, had to reassemble the carbs multiple times before before I got them right.

[Ssicbx]

What jets are you running, what exhaust and air filter(s)?

[Dave B]

Just holding fire
just realised only firing on 3 cylinders

[wildtapholer]

Mine was only running on 2 cylinders, but mines not been out for a run yet, waiting for a few more bits.