2 Strokes and there oiling systems, how does it work?

[QuicktimeRacing]

A buddy of mine says that his Banshee has no oil in his crankcase and that the only thing that lubes the crankshaft and bearings is through the oil in his fuel mixture. Is this the case? I have yet to tear down my motor on my 250r and this two stroke stuff isn't quite what I am use to. Are there differences between the brands (i.e) Yamaha and Honda) and if so what is the benifit to each? -Trent

[Jester]

premix is what lubes the crank/piston area.
I'm using a 40:1 mix of my prefered 2 stroke oil premix.


you do have oil in the tranny/clutch, and you should change that often.

[Tom TRX250R]

There are two seperate, sealed oil systems on a two stroke. The crankcase which is your gear oil and lubricates your transmission and other gears. Then there is the premix which two stroke oil is mixed at a varying ratio (mine is 32:1) with gas at which lubricates the cylinder walls, piston, and crank. Basically all brand of two stroke engines (ex. Honda or Yamaha) are identical in lubrication as described above. Unless like the old Kawasaki H2 stock which comes with a oil injection system. This is identical except for instead of mixing gas you keep the injector jug full of two stroke oil which mixes the correct ratio for you as needed.

[250R-Dee]

Actually there are quite a few two strokes that have oil injection.
Blasters
CRM80~500 street version (Asia/Europe)
RMX250 street version (Asia/Europe)
KDX125~250 street version (Asia/Europe)
Most of the 2 stroke street bikes and snowmobiles have oil injection

Like everybody else said: premix oils the cylinder while the tranny fluid takes care of the crank bearing.

[Tom TRX250R]

I know there was more like the Blaster for instance, I was just naming an example. And the one example that came to mind was the old widow maker Kawasaki H2!!! What better example than a 750cc, three cylinder, 2 stroke!:devil:

[250R-Dee]

I was just supporting your info bro':D .

Oil injected 2-strokes are everywhere over here.:chinese:

[wilkin250r]

Originally posted by QuicktimeRacing
A buddy of mine says that his Banshee has no oil in his crankcase and that the only thing that lubes the crankshaft and bearings is through the oil in his fuel mixture. Is this the case? I have yet to tear down my motor on my 250r and this two stroke stuff isn't quite what I am use to. Are there differences between the brands (i.e) Yamaha and Honda) and if so what is the benifit to each? -Trent

Check out the tech article on 2-stroke operation (http://www.atvriders.com/articles/twostroke.html) .

You'll see that the incoming fuel/air mixture gets sucked into the crankcase first, compressed, and then shot into the cylinder. This is why you can't have oil in the crankcase, or else you would be blowing ungodly amounts of oil into your cylinder, which would foul your plugs and smoke something god-awful. So you only have a little bit of oil, added to your fuel.

There are a few different 2-stroke designs around, such as rotary valve, reed valve, and others. However, on the quads, they're all pretty much the same, they all use the reed-valve design.