The Plus 21-5T is awesome.
I haven't had any problems with mine and it has balls of steel!
It goes like the clappers with tonnes of torque and pulls hard all the way to the top.
I've put over 7 litres through mine now and it still has tonnes of compression.
I can't turn it over with my finger from under the truggy!
Bearings and conrod are like new and showing no wear at all.
It is probably one of the best engines Novarossi has ever built if not THE BEST!
Do your self a favour and get one of these beasts.
You will be very happy.