When I engage the mechanical secondaries, it bogs the car. Free revving, it does fine, but when I get to 4000+ and open them up, it falls on its face.

Also, I know what the needle and seats look like, but has anyone seen a needle and seat that was a glass ball? Seriously, this thing looked like it was plucked out of a mini marbles bag or something. Works great though.

 

too much fuel?

 

ok, are you at 4000 RPM's and then deck it?? In other words are you already into the gas some and then punch it around 4K?

What is probably happening is you have ran out of the accelerator shot and are bogging for lack of fuel.

Sterling does a mod on his carbs that allows more capacity on the accelerator pump. Prevents bogging when cracking open the secondaries.

Dunno about the marbles!!

 

Cruise over to Sterling's site and talk to him about your marbles...

www.sterlingmetalworks.com/bymc

 

The needle valve you describe sounds like a GroseJet. I know that Rotary Engineering (the original) used to put them in their Nikki rebuild kits. I used one on mine for a bit, but had trouble with the float chambers flooding so put the regular needles back in.