Tm kz r2 total black

Hi, I am new here, in fact also new at TM KZ R2 shifter.

Recently I start to drive shifter with R2 total black, with mychron 5S 2T.

Could soemone advise me

  1. what is the optimal high & low EGT for R2 ? I am using main jet 170 with 550C & 350C, they are too low ? Samller jet ?

  2. what this th revolution limite ?

  3. how many working hour do I need to chnage piston, rebiuld it ?

Sorry to sound slilly.


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  1. Yes too low. 400/440 min and 600 max safe, you can push to 625 to find the optimal, after that is danger zone (the engine won’t instantly explode at 630 or even 650, just be careful as you approach the red zone here)
  2. There are no rev limits on a KZ but try to keep it around 15,000/15,500 max if you can, and that’s usually a slight overrev in downshift. Properly jetted engine should hit around 15,500 on the stand, that is a good sign of what the engine can do on its own power. Occasional aggressive downshifts are ok (I’ve seen people hitting 16.5/17k) but it’s not healthy
  3. 6 hrs/60 lt piston, 12 hrs/ 120 lt open and inspect crank, at minimum pin and bearing. Rod can run one more piston at 18hrs/180 lt. This will keep you safe. Competitive use, more frequent, hobby use turning laps and running rich you can extend

Adding to Andy’s advice, you’ll notice the engine will simply stop accelerating as it get to its “natural” rev limit. Experiment with shift points to see what you particular engine likes.

EGT - you probably want to target around 600 to 650.

Comparing data, upshifting around 13800 rpm is a pretty good target. I tend to short shift early at around 13100 and I lose noticeable time on the straights by doing this compared with others shifting around 13800.

Thank you, Andy, your advises are very import for me. I will try to follow them.

When you say, 6hrs/60lt, the 60lt meas 60 liter of gasoline?

Also, may I understand the oil & gasoline mixture % ? 3% is good enough ?

Thanks for tips James, I will try.

Thank you Rod, noted rev between 13,100 & 13,800 is good timing to upshitfing. I will try.

I don’t use percentage much when mixing, but I believe its 4 to 5%. I usually mix at 6oz to the gallon using freedom units :rofl:

You want 5-6% for oil ratio. Elf HTX 909 or Motul

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4% of oil in KZ. Yes 60 liters of fuel or if you have an hour meter it’s about 6 hours of running time

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Got it, Thank you Rod.

Thank you Andy, you guys are helpful here, lucky me to find this forums. I am from Taiwan, where TM KZ is very few, and very limited on technical knowledge… I think I will keep coming to rise questions.