KTM Forums banner

2 Stroke efficiency, power and fuel injection questions.

2K views 3 replies 4 participants last post by  serialize 
#1 ·
One of the many pro arguments for 4 stroke engines is their efficiency, torque and power delivery. I PERSONALLY prefer the feel of a 2 stroke but understand some of the disadvantages of them. I'd like to discuss some of them here to get some opinions and facts.

For starters, why are 2 stroke engines dying out? My guess is the emissions complaints as well as their fuel efficiency, but are there more reasons? I remember reading some people saying 2 strokes can be quite efficient too, is this true? What mechanically is stopping the addition of valves seen in 4 strokes from being added to 2 strokes? Can they be fuel injected as well? Another question, are 2 strokes really twice as powerful for their displacement compared to 4 strokes?

I have ridden 4 strokes and don't enjoy their power delivery or feel. I love the simplicity and noise of the 2 stroke engine, and I wouldn't want it to die out. Is there room for improvement on these machines and will they die out anytime soon?
 
#2 ·
#3 ·
2 strokes rule. Initially it was an emissions problem, but yes, Baja is correct. They are now working with injected 2 strokes and I think they are running an oil injection system straight into the crank, rather than blending it in the fuel and burning it. Obviously a 2 stroke will always have more potential for power as it doesn't have a wasted stroke. 2 strokes can be very reliable and probably seem that way lately due to the fact that a lot of 4 strokes now are being produced with very weak valve trains. I personally prefer slapping a set of rings in every now and then rather than grinding valves, re-seating, swapping out guides, replacing chains, repairing cams...... the list goes on.
 
#4 ·
Adding valves to a 2-stroke would make it a 4 stroke (you would have to add the 2 extra cycles to run the valves, make compression, etc.

However there is an emergence of oil injection. Currently being done on Beta, it's oil injection into the carb making the mixture electronically.
I recently bought a 250rr-race (Beta) specifically that model to avoid the oil-injection (the race models don't come with the oil injection) to avoid an additional breaking point.

2-Strokes are making a huge come back, look at the used market on 2-strokes and you see some very high priced old used bikes. Also Yamaha came out with the YZ250X recently which is amazing bike and I had a very hard time deciding on which to get between the Beta and the YZX, but in the end it was price as a decent used Beta popped up and I jumped on that deal otherwise was looking to buy the YZX new. No oil injection on the YZX but it's a proven design and engine and is reliable, lot's of parts availability, etc.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top