Home Forums 2-Cycle Racing KPV issues? Reply To: KPV issues?

Tim Koyen

Some builders set their carbs up to run with the high completely closed, some like it cracked open, and others like it open even more.  Be sure that you and your builder are together on what the proper settings are for your carb(s).  And just because the carb settings were at one setting this weekend, doesn’t mean they will be exactly the same next weekend.  The air quality plays a big factor in the carb settings, as well as what gear you are able to pull.  When the air is crisp and dry, you may be able to run a very small rear gear, but the next weekend, they weather may be entirely different, and may require 3 more teeth to get the same RPM.

Also, don’t get fixated on what RPMs you’re turning.  Every engine is a little different.  Some like have a higher power band, and some lower.  I’ve seen guys running identical lap times with a 500 RPM difference between them.  I’m not saying that you should disregard the Tach, just don’t rely entirely on that to tell you where to go from here.

This is slightly off topic, but I see that you’re a Data Guy…  Karts can only be properly tuned on the track; based on the conditions of the day.  Grip level, tire condition, weather, fuel, and driver condition are all factors that go into getting everything just right.  You can’t look at a chart, set the kart up at home, and expect to have it perfect when you hit the pavement.  Get a baseline setup, turn some laps, and see what the conditions of the day warrant and what the kart wants.  Data will help you get that baseline, but you do the rest of the work at the track.  That’s the FUN part!

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Don't bother PMing me, it doesn't work. Email is best: tim@kartlift.com.