KAN YOU RUN A 4STROKE 125 PIT BIKE ON 95 UNLEADED INSTEAD OF 91 UNLEADED??

98 is for high performance , high compression engines
MB may recommend it and you can check it out in the owners hand book or by asking a MB service dealer
All engines run satisfactorily on 95 and the difference in performance generally doesn't offset the higher price for the 98

Rings or oil in the gas.

pull cover on magneto and check for loose pickup coil.

Nice bike, its a clutch problem, you might need to rebuild the clutch, beef it up a bit.

It creates the spark to your spark plug

Tryd go to auto shop and check the carburator of your motor and clean your air filter adjust air setting in carburator and put a new fuel pump check fuel setting in carburator

planetminis.com/forums/forum.php

ssrpitbikesusa.com/SSR-pitbikes-USA-tech-support.html

It sounds like you need to overhaul and clean out the carb. There may be jets and passages partly clogged and are restricting your fuel flow at wider throttle settings.

THE BEST THING IS TO USE WHAT YOUR SERVICE MANUAL CALL FOR. REGULAR UNLEADED 87 OCTANE - UNLEADED PLUS 89 OCTANE - SUPER UNLEADED 91 OCTANE. UNLEADED PLUS ITS OKAY. TO USE EVERY NOW AND THEN I WOULD USE 87.YOU CAN RUN 87 - 89 OCTANE.BUT DONT RUN 91 OCTANE ITS FOR THE HIGH PERFORMANCE ENGINE.