Tecnical talk 1 - 2 stroke motor and why I love it and you hate it
My first and 2nd bike were both 2 strokers. First bike was a made in Thailand single cruiser commuter/mini cruiser with a pretty zesty 2 stroke engine, similiar to the NSR150 SP (commonly seen with the Repsol paintwork) that's so prevalent here in Singapore. Here's a pic of me and my dear on it, in motion.
It's a very reliable bike, brought me to Hatyai without any difficulty. A bit low on power but still can outrun most if not all 1600 cc cars on acceleration. Top speed only 130 km/h though.
Well my 2nd bike, till now haven't ridden much though had an
unfortunate incident already, is reputed to be one of the best cornering bikes in production. Already the 250 cc 2 strokes are known to overtake much bigger bikes in corners and we can still see them in MotoGP250. They aren't very useful as road bikes, due to the powerband/torqueband and insanely high fuel consumption (11 km/l for me). The following dyno chart of a RS250 and 4 stroke RVF400 shows that a 250 cc 2 strokes produce as much or even more power that a 400 cc 4 stroker. However, most of the power of the 2 stroke is achievable at high rpm (approx 9000 rpm) and thus the application to racing.
Dyno chart of Aprilia RS250. Note the gentle slope in the beginning followed by the abrupt steep slope when the "valve opens".
Dynochart of Honda RVF400 (NC30). The power is more readily available across the rpm curve.
That's all.... and for last 'motorcycle speak' a very good diagram to illustrate why
a. 2 strokes sound the way they are (or rather 2 strokes exhaust have a big chamber).
b. why they waste fuel and considered a pollution (inefficient exhaust and fuel separation).
c. the source of power, lies in the ignition every 360 degrees (opposed to 4 stroke having 1 ignition every 720 degrees of rotation).
Posted at 01:49 pm by
snowparang
