There is obviously as small debate between 0.55mm or 0.60mm jet sizes to use for the Daytona. I understand the pro and cons of either argument. However what really interests me is the question if a 0.55mm jet could be too small and risk a to meager running engine and generally risking anything especially on long runs like 1000km on a given day? Terry...Brian...... your thoughts are as always extremely welcome
In Daytonas typically we don't feel the need to increase the size of the low speed jets. I can't really imagine needing to do it. They already tend to run rich in that part of the envelope. Also as far as damage is concerned from being borderline lean, at the low power settings low speed jetting implies I can't see it happening. Damage from lean jetting is almost always at high engine output levels where high temps are present due to the motor being worked hard. In that condition it is running on the main circut and the low speed circut has very little influence at or near wide open throttle. Take that situation (very high output level) and make a motor too lean on top of it and damage from excessive combustion temps or detonation is quite common.
Driveability is really the main concern on the low speed circut.
If the car is lean on the low speed circut I would check for correct float level adjustments. Those carburettors are very sensitive to float level on the low speed circut and too low a level will create problems.
All that being said the DCN20 carbs used 55 and the DCN21 carbs used 60. The float levels are 6 and 4mm respectively.