Question:
whats the differents between a 2-stroke and 4-stroke
SAN BERNARDINO area!! I need a good mechanic for my Harley 85 Softail?
motocross bike engine?
Answers:
Im looking for a centre stand for a gpz900r ninja anybody got one for sale?
It used to be the case (particularly in the case of race engines) that 2-strokes generally had a higher power output than 4-stroke engines for the same engine size (cc) hence they were very popular in grand prix and motocross sport but these days development of four stroke engines has got to the stage where components are so light and the engines able to rev so highly that this is generally thought to no longer be the case.What a 2-stroke engine does is complete one revolution in just 2-strokes of the piston within the engine, first stroke is induction and compression the second ignition and exhaust - all of which is controlled by piston porting instead of with more sophisticated valves and cam arrangements as in 4-stroke engines. Obviously four stroke engines require four complete strokes before one complete revolution is completed.
The fact that a 2-stroke engine can complete a revolution in basically half the number of strokes as a 4-stroke gives it a high potential power output, and obviously given that there's no reciprocating mass in terms of valve gear means that it also has good engine acceleration and the ability to rev quite highly and freely.
The other main difference is in the lubrication, conventional 2-stroke engines use a total loss lubrication system - that's to say that the oil which is used to lubricate the engine is all thrown out of the exhaust and so they rely on either having fresh oil continually pumped into the crankcases or alternatively run on premix with the oil mixed to the right ratio in the petrol.
Drawbacks are of course that this method of lubrication is far from being as good as having an engine running in a continuous oil bath with recirculated lubrication as with 4-strokes which does have some effect on engine life. The other factor is fuel economy, having no real valve system means that some fresh fuel inevitably ends up going out of the exhaust to a certain extent which usually means poorer fuel economy than a 4-stroke equivalent. That and the pollution factor, unburnt oil being released into the atmosphere as hydrocarbons just isn't good for the environment mean that the 2-stroke engine is something which tends to be increasinly restricted by new emissions regulations - makers these days pretty much can't produce 2-stroke bikes above 125cc for road use for these reasons as the emissions levels just don't pass current tests.
These are simple engines to construct however and in smaller engine sizes can be reasonably economical, many sub 125cc bikes will use 2-stroke engines for these reasons and generally because its easier to get a certain degree of power from them than with small 4-stroke engines - i.e. most of the derestrictable sports 125s can be derestricted for as much as 30hp which is when you think about it 240hp/litre that shows the potential of 2-stroke engines in terms of power outputs.
Has any one ever rode a cr500AF i heard they only made 20?
In the simplest of terms, a two-stroke engine has a compressions stroke and fires every second time the pistons reaches top-dead-center. The four stroke engine has a compression stroke and fires every fourth time the piston reaches top-dead-center.In addition, two stroke engines burn a combination of oil (to provide lubrication) and gasoline, while four stroke engines simply burn gasoline and lubrication is provided by an oil sump in the bottom of the engine.
anyone else gotten into a bad motocross crash?
A 2 stroke makes power every 2 revolutions and a 4 stroke every 4 thats why they make twice the powerMore Questions & Answers ...
This article contents is post by this website user, CarQnA.com doesn't promise its accuracy.
Copyright 2006-2008-2007 CarQnA.com. All Rights Reserved.