Joined Jul 2001
3K Posts | 1+
El Sobrante, Ca. 94803
Here is my reply to an Email regarding a heavy throttle hesitation with one of my Jet Kits.
I believe said reply will prove of overall benefit as it is not specific to my product.
Hi Giorgio.
Completely warm up the engine by riding.
Adjust pilot fuel screw plus / minus one turn from the initial 1 1/2 turn setting to achieve best overall running.
Note:
Avoid prolonged idle and / or incomplete warm up by riding.
Above idle small throttle openings (1/8 - 1/4) adjust the pilot air screw (under inlet bell) out for lean in for rich. You must then most likely readjust the pilot fuel screw. Idle rpm should be roughly 1600.
Above idle to roughly 1/4 throttle is very sensitive to pilot air screw settings.
All settings are designed for smooth throttle application. Snapping the throttle and / or wide open throttle below the power curve will create a flat spot. If such is your style simply raise the needle (lower the clip) and / or install a larger main jet (i.e. #170)
Best power is most often made with a #150 main jet however only @ wide open throttle high rpm.
Best torque with a #160 main jet however only between 4,000 rpm - 6,000 rpm 3/4 to full throttle.
Best "snap throttle" (i.e. heavy load / low rpm) performance will call for raising the needle, a larger main fuel jet and possibly activating the pump. Unfortunately said changes reduce performance potential.
Rolling the throttle on as opposed to snapping, keeping the engine rpm in the heart of the performance range (above 4,500) before going above 1/2 throttle has proven superior with regard to reduced lap times and improved single track performance as opposed to richer tuning and / or activating the pump.
It is however possible that your particular style (maybe a former two stroke rider and / or accustom to the long pull of say a conventional round slide carburetor as the Keihin is very quick) may have difficulty with rolling on the throttle. In such cases richer tuning as outlined and / or pump activation will assist.
Hope this helps and please keep me posted.
Sincerely,
Dale
I believe said reply will prove of overall benefit as it is not specific to my product.
Hi Giorgio.
Completely warm up the engine by riding.
Adjust pilot fuel screw plus / minus one turn from the initial 1 1/2 turn setting to achieve best overall running.
Note:
Avoid prolonged idle and / or incomplete warm up by riding.
Above idle small throttle openings (1/8 - 1/4) adjust the pilot air screw (under inlet bell) out for lean in for rich. You must then most likely readjust the pilot fuel screw. Idle rpm should be roughly 1600.
Above idle to roughly 1/4 throttle is very sensitive to pilot air screw settings.
All settings are designed for smooth throttle application. Snapping the throttle and / or wide open throttle below the power curve will create a flat spot. If such is your style simply raise the needle (lower the clip) and / or install a larger main jet (i.e. #170)
Best power is most often made with a #150 main jet however only @ wide open throttle high rpm.
Best torque with a #160 main jet however only between 4,000 rpm - 6,000 rpm 3/4 to full throttle.
Best "snap throttle" (i.e. heavy load / low rpm) performance will call for raising the needle, a larger main fuel jet and possibly activating the pump. Unfortunately said changes reduce performance potential.
Rolling the throttle on as opposed to snapping, keeping the engine rpm in the heart of the performance range (above 4,500) before going above 1/2 throttle has proven superior with regard to reduced lap times and improved single track performance as opposed to richer tuning and / or activating the pump.
It is however possible that your particular style (maybe a former two stroke rider and / or accustom to the long pull of say a conventional round slide carburetor as the Keihin is very quick) may have difficulty with rolling on the throttle. In such cases richer tuning as outlined and / or pump activation will assist.
Hope this helps and please keep me posted.
Sincerely,
Dale
