Sudden power loss at certain RPMs

When I ease off the throttle, the bike starts slowing down and the RPMs dropping as normal. But at a certain point (for 2nd gear - 4.5k, for 3rd - 5.5k, for 4th - 6.5k RPM… or thereabouts, not 100% on figures), just for a brief moment, the bike slows down hard (feels like extreme and very sudden engine braking). If at that point I open the throttle back up, as soon as that same RPM point is reached, the bike lunges forward from too much power.

What makes this even more annoying is that it’s really hard to reproduce. I commute daily 30 miles, but this only happens maybe once a month. When it happens, the problem will persists until I reach my destination (e.g. work), but once I head back some hours later, it’s all working fine.

The problems is a bit specific and hard to explain. But I did manage to find a somewhat similar instance on the internet wherein the throttle cables weren’t adjusted properly, which was causing the issue. So, I’m going to check that. Anything else worth investigating?

The bike’s a bandit 650 FI.

TPS could be playing up

Fueling, vac hoses, tps?

leaking air line

I’d start with the spark plugs, caps and and HT leads :wink:

Has it suddenly become a 2 stroke?

Had similar prior to regulator issues, check connectors too.

Helpful advice here. It’s always best to check. Maybe put some 2 stroke oil into your tank just to be sure.