Home Forums Tech Talk Kt100 WB3A on track tuning help Reply To: Kt100 WB3A on track tuning help

#35941

patrick hubbell
Participant

You shouldn’t need Teflon tape to seal any part of the carburetor.  It is normal for the needle to pop once and then leak down.  You have a Mychron and are able to download data, excellent. All you need is EGT and you are set.

Why EGT over CHT.  EGT responds instantly to changes in temperature. CHT responds much slower to changes in outside temperature, casting type, pipe etc. When tuning with EGT, you always want the temp to be increasing to some unknown maximum and it should increase quickly as soon as you open the throttle. Start with the “L” speed needle set at 1-1/2 turns and the “H” needle at 1/4 turn.

Note: the low speed circuit feeds gas to the engine up to 12,000 rpm then the high speed circuit opens and both high and low are feeding the engine.

Once the engine is up to temperature, open the “L” needle to 1-3/4. As you get close to the end of the longest straight, the engine may be to rich and loose power. This is called “four cycling” and sounds like “blaaaaaa” open up the H needle an 1/8 turn more, if the engine is still 4 cycling then lean the “H” needle 1/8 turns at a time until the engine runs crisp all the way down the straight. If the engine is lazy off the corners , richen the “L” an 1/8 turn.  If the engine is stil lazy then you might have to adjust the pipe’s length, the gear ratio or the stall speed of the clutch.