Rotax max upgraded to evo

2 Stroke Kart Engine Forums
1

I have a Rotax Max Upgraded to evo.

It will rech awkward pretty easily and quickly.

However, it hangs flat at 12 for a long time and then will quickly shoot up to about 14k quickly and then bounces and erratically.

I assume the bounce is a rev limiter, but I can’t figure why it gets stuck at 12 k for ow long.

It seems like a switch is turned on after a good while ar 12x then it takes off.

Any ideas?

2

Sticky RAVE valve, or valve system not working correctly.

3

The valve does open at about 7k and stays open but this is a good point that I need to check that it’s opening all the way when it should. Thanks

4

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Power drops off fast after 11500. Are you running exhaust temp? Are you confident with your jetting?

5

Thanks. I had known this, so I wasn’t too concerned about not getting above 12k but I felt it was a problem that it wouldn’t even go past 12k.

I talked with a tuner and he said a Rotax will hang at 12k and then later rev up to above 14k when on a stand. He said if on the track and running right, it should not hang at 12k.

I’m still going to check and clean the power valve.

Thanks