Re: FUEL ADDITIVES FOR OLDER BIKES ?

Posted by shinyribs on Apr 02, 2012; 4:10am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/FUEL-ADDITIVES-FOR-OLDER-BIKES-tp3875167p3876730.html

Oil in the combustion chamber can be bad. Y'all know I am no motorcycle mechanic as this is all still fairly new to me,but I do know a fair amount about V8's. Especially high performance ones. I consider the motor of a CB750 to be a high performance engine.The HP per cu. in. of these bikes is phenomenal IMO. Roughly 1.5 HP/cu.in. Thats pretty impressive!

With the nitrous and blown motors we have run in the past there were two number one killers of pistons,and therefore engines. And that was oil in the combustion chamber. The oil deposits dont want to burn off as quickly as the gasoline does.When it does decide to ignite it would either cause preignition or it would pop the top of the pistons off. The preigniton is a result of the oil firing,basically at random.The out of sequence firing will try to drive the piston down (as it should) but while the piston is trying to go up since it was out of sequence. Hammered out rod bearings and cracked piston heads are the result. Oil puddling around the top compression ring trying to ignite will cause that ring land to pop off.

Of course all of that is worst case scenario,but it is the result of oil in the combustion chamber. I have seen engine run on oil alone.A buddy had one puke out an intake gasket under high boost and the oil it started sucking in thru the lifter valley wouldn't let the motor die even after he killed the ignition. Compression firing like a diesel engine.

We've all seen or owned an engine that burns oil from worn rings.So it is obviously not a time bomb exactly,but not really a good thing either.