Tuning Tips
You may have heard stories about the difficulties tuning multiple carburetors, but the truth is it isn't difficult with either the Six Shooter or Demon 98s. Barry Grant recommends the following procedure:
Set the float levels of all three carburetors just below the mid-way point on the sight-glass windows. Check the ignition timing, 14 to 16 degrees initial is suggested. Once the engine reaches normal operating temperature, set the idle speed, then find the best idle quality by adjusting the two idle-mixture screws (either inward or outward) a quarter turn at a time.
Trouble Shooting
Like anything mechanical, there may be carburetion issues to deal with from time to time. Here's some troubleshooting advice from Barry Grant.
* Blackens Spark Plugs While Driving:
Use smaller main jets, lower float levels, lower power valve number, and reset throttle plates (butterflies).
* Blackens Spark Plugs At Idle:
Reset throttle plates, tighten mixture screws, lower float levels, reduce fuel pressure, clean air bleeds, use smaller number power valve, and increase initial ignition timing.
* Backfires Through Carburetor:
Loosen mixture screws, increase size of the accelerator-pump nozzles, raise float levels, reset throttle plates, increase size of the main jets, and check ignition timing.
* Backfires Through Exhaust:
Tighten mixture screws, decrease squirter size, lower float levels, reset throttle plates, decrease size of main jets, and check ignition timing.
* Doesn't Pull Well At Wide-Open Throttle:
Increase size of main jets, raise float levels, and increase fuel pressure.
* Float Levels Won't Adjust:
Reduce fuel pressure, clean needle and seat assemblies, and ensure floats move freely.
* Float Bowls Drain Down After Shutoff:
Retighten bowl screws and power valve; replace bowl, metering block, and power valve gaskets, and clean the air bleeds.
* Fuel Drips From Boosters:
Lower float levels, reduce fuel pressure, and reset throttle plates.
* Fuel Drips From Accelerator-Pump Nozzle:
Loosen tension on the spring-loaded accelerator pump arm.
* Fuel Leaks From Throttle Shaft:
Lower float level, reduce fuel pressure, clean or replace needle and seat assembly, reset throttle plates, clean air bleeds.
* Fuel Shoots From Vent Tube:
Lower float level, reduce fuel pressure, clean or replace needle and seat assembly, and ensure float moves freely.
* No Adjustment On Mixtures Screws:
Reset throttle plates, increase initial ignition timing, lower float levels, and reduce fuel pressure.