Trying to set base idle - engine stalls when I clamp by-pas

[dantvrgriff]

Hi

I was trying to follow the bible to set the base idle on my 97 Griff 500 by clamping the bypass hose so the I could adjust the bypass screw on the throttle body to a 500 rpm tick-over. When clamping the bypass hose the engine stalls immediately. Any idea what could be the cause of that ?

Cheers

Dan

[blitzracing]

have you tried getting it to run by turning the base idle screw anticlockwise? If it has worked in the past (as it should have) and it wont now idle on base setting only, then there is a mechanical or electrical reason why the engine is not running as well as it should.