Cracked block, worn-out rings, hole in a piston, valve-stem seals, and several other less expensive things if you're lucky.
That is the burnt two stroke oil. it is pretty normal
Oil in the exhaust is part of the two stroke design but if you have too much, you should check the fuel/oil mixture or the oil injector settings.
Oil spitting through the exhaust of a Yamaha PW50 typically results from an overly rich fuel mixture or improper oil-to-fuel ratio. If there is too much oil in the mixture, it can lead to excessive oil burning, causing it to exit through the exhaust. Additionally, a clogged air filter or exhaust can exacerbate this issue by restricting airflow, leading to incomplete combustion. Regular maintenance and correct fuel mixture ratios are essential to prevent this problem.
burning oil
Burning oil
Broke rings on pistons
Piston rings or Rich oil .
Head gasket
Doesn't matter what type of vehicle, this indicates an exhaust leak and an oil leak. The burnt oil and the exhaust, get pulled into the cowl which is where the air for the interior comes from! Not very healthy...
Seriously worn piston rings and more than likely a broken oil ring.
A 1996 CBR 900RR may backfire and spit fire out of the exhaust due to a few common issues. These can include an incorrect air-fuel mixture, which can lead to unburned fuel igniting in the exhaust, or a malfunctioning ignition system that causes misfires. Additionally, a clogged or damaged exhaust can also contribute to backfiring by restricting proper airflow. Regular maintenance, including checking the fuel system and ignition components, can help resolve these issues.
A vehicle that emits blue exhaust is experiencing an oil leak that has seeped past the engine seals and started to burn with the fuel. It indicates either a blown head gasket or an engine oil leak.