I’ve been running the ‘stock honda’ package for 3-4 years now and I’ve been karting for much longer, so I hope I can pass on some knowledge. One of the (only) downsides to this class is that there is a real lack of info say compared to a 206. Hope I can help.
Jim is right it sounds like the shift lever doesn’t have enough throw. Make sure that the J-arm which connects to the shift shaft on the motor is as close to 90 degrees to the ground as possible. If it is leaned forward too much it will bind. Also, one thing I’ve noticed with novice drivers is that they let off the gas waaaay too much when up shifting. It only takes a 2-300 rpm drop to up shift, which basically translates to the blink of an eye. I also notice that new drivers tend to bounce their throttle foot. There is a back-forward motion on the up shift and its very easy to hit the gas premature and miss the shift. This might explain the rev. Double throttle springs are a good and cheap buy. Another trick is to shift by ‘squeezing’ with your fingers while your thumb is still wrapped around the steering wheel. Not only is this quicker but less fatiguing. And yes the #1 cause of missed shifts is fatigue!
Down shifts should use NO gas until you are the master of late braking, and then it’s only a teeny bit and corner specific. Fyi in my opinion learning hard threshold braking is one of the most overlooked skills for new drivers. Any guess to where 8/10 passes happen?
The CTS chassis are good but they weren’t produced in large numbers. I believe they take Unico style body work. But look up the measurements online and compare to your chassis.
Also what carb are you running? If you have the stock PJ your will deff be running out of top end. PWM is the way to go in my opinion and they can be had for a little cheaper by searching for a mid 90’s Yz250 carb instead it was stock on that bike I believe and maybe a few others.
Other top end killers:
Fouled plugs should be new Br9eg or Br10eg
Electrical. Solder everything! Connectors are convenient but they fail.
Exhaust. Leaks and cracks will do weird things to the mixture and make it very hard to read.
Lastly Jetting!!!! This is one of the finer points and needs a lot of trial and error. Go slow and read your plugs.
What is your Fuel:Oil ratio? It should be 24:1
Hope that helps.
" Turd Ferguson is real and he will pass your a** "