Topic: running lean?

[cappy]

Hello,

Just rebuilt carbs on my CB750 72' with keyster kits.  Kit came with 40 pilot 110 mains.  Clip needle position 3rd slot.

Stock engine, timing good, standard airbox with K&N filter. 87 octane, Mac two headers into 1 on each side.

Running about 3K rpm just over 40MPH hit WOT and it's like someone turned the key off.  The original mains were 110 and it seemed to run good.  I have a set of 120's to try.  Would this be sudden surge be considered a lean running symtom?

Ohh, one other thing the float levels seemed to be high b4 the rebuild so I reset them all to 26mm.  This may have helped the 110 run richer before the rebuild.

Thanks in advance.
Greg.

[Gordon]

You can't accurately diagnose a lean running condition just by the way the engine runs.  Pull the plugs and see what they look like to get a better indication of the mixture.  Better yet, do a few plug chops at various throttle positions for an even better indication. 

Having said that, none of the pre-accelerator pump bikes respond well to whacking open the throttle.  You should be able to roll it open fairly quickly and get good response, but opening it too quickly will result in a temporary lack of fuel for the amount of air being sucked in.