CV carbs mix screw 8.5 turns out?

[Anonymous]

I'm just getting around to tuning up the CV carbs on my 81 450 twin. Cyl. #2 has the main idle adjustment screw so I unplugged #1 and cranked up the idle to where #2 runs the whole thing. Then I fiddled with the mix screw on #2 until I got the highest revs I could, which was at 8.5 turns out. That's a lot; is it too much?

The screw I was playing with was the only one I could find, and is near the engine intake. That is the mixture screw, right?

Michael

[Anonymous]

I should mention that I couldn't find any "sweet spot" on the mixture screw. It just went up by 20% as I got to about 8 turns. Continued on to 13 and it didn't get any higher.

Michael

[cbxchris]

Most times it ends up being from around no less than 1 to no more than say 4. That sounds excessive but I will admit I am not familiar with that bike at all. But most carbs are the same generally for all bikes.

[KEITH KRAUSE]

I'm not familiar with your carbs either but I'm positive 8.5 turns is excessive. I think your rpm's max out at that point because your creating a vacuum leak. As stated earlier, the "range" for typical mixture screw settings would be possibly as little as 1/2 turn out and no further than 3-4 turns out. Somewhere in that range your rpm's should rise to a maximum and level out. If you continue turning, you are beyond the range of that screws ability to regulate the mixture.
If your carbs are otherwise operating correctly, and adjusting the screw in that range does'nt help, then changing jet size is the only thing you can try.

[Detman101]

Jesus, 8 turns out?? Mine are barely sitting in the threads at 5 turns out. But Dynojet insists that is the correct setting.
Maybe for an airplane but definitely not a motorcycle.

:roll:
Dm of mD

[saaz]

The normal range for pilot screws is only about 1/2 to 3 out. If any more or less either there is a problem as Keith has said, or the pilot jet needs changing.