Tuesday, February 24, 2009

Of oil ratios and spot on jetting

Since the last few weeks that the fuel prices have come down(thanks go out to our so called government) my calculations for the right amount of oil to fuel ratio for a given sum of money that I spend filling up my trusty old (excuse for)stock RX 135 5 speed is all haywire.

Some quick calculations tell me that I was running around 23.5 ml of bunk oil to a litre of fuel and revving the engine all the way to the 9k rpm mark in atleast the first three gears.

Now I am a guy who is really anal about the amount of oil I run for a given amount of fuel because of the fact that it has affects ranging from pistons, rings, and cylinder wear, to carbon buildup, to crank bearing life and your jetting too to some extent.

I have run almost every kind of half decent oil you can get in our country, to the top of the line Motul 800 fully synthetic 2t oil, which costs an arm a leg and probably a nut too for the amount of oil I run through in a month. I have heard people claim that running 4 stroke gearbox oil makes the engine tick over very smooth. I would like to enlighten people that it doesnt because there are characterstic properties which a 2 stroke oil is supposed to have but the gearbox oil doesn't.

One thing I noticed was that the bike never smoked a bit even while running crappy bunk oil in that particular ratio, doesn't mean you go ahead and run that ratio to cure your bike's smoking problem and seize the bike and press charges on me. Lotta people do wonder that why am I running bunk oil when I run Motul 800 most of the times, well one of my excuses is that the bike is running in. Another being the last plastic measuring cup I had broke(is this word right? or does it more describe my financial state?), so I wasn't able to measure to the thousandth of a mililiter of oil for that perfect oil to fuel ratio.

The other day I filled up the bike with about 7 odd litres of fuel with enough of Petronas Sprinta 5000 fully synthetic 2t to get the ratio to about 27 ml of oil to a litre of fuel. Something I noticed immediately is the fact that the bike did start emitting a small amount of smoke(not something which you can use instead of a smoke bomb) and it became utterly smooth compared to before, I wouldn't really contribute that to the fact that I ran more oil but that the fully synthetic oil in general was way better than the bunk crap we generally get.

I run a NGK BR9HIX(pretty cold for a stock bike) spark plug on my bike which used to be this perfect tan brown color with a white ring on the electrode for that perfect timing which was set at 26 deg BTDC on the RDD RX Digital CDI v2 that I am running on my bike. With the new oil ratio I still have the tan brown color but there are some sooty black deposits which point towards the fact that I can lower down the amount of oil a little.

Next test will be with the precise amount of oil measured precisely for that perfect mixture ratio to see what kind of readings I get from the spark plug.