Rotax max upgraded to evo

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?

Sticky RAVE valve, or valve system not working correctly.

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

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

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.