LANCER wrote on 06/09/10 at 12:50:55:

Since I've been on here you seem to have troubles getting a S40 running you must be doing something wrong.

Good information go tell your kid btw what was the last 2 cycle street bike you had

bill67 wrote on 06/09/10 at 13:06:15:


hmmmmm,  what's up man ?

Serowbot wrote on 06/09/10 at 17:20:26:

Motorcycles quit making 2 cycles,But snowmobiles didn't.With rotary valves and reed valves which gave the 2 cycles lower end torque without hurting the higher end power.650 cc motors were putting out over 100 hp at only 8000 rpm,That was 20 years ago.Bottom line 2 cycle much more torque than 4 cycle.How would you like a S40 650 2 cycle putting out 100 hp.And it would be maybe 40 pounds lighter,And don't forget the good sound you get from a 2 cycle

Here's some fuel for that fire -- two strokes hit their peak development in snowmobiles, outboard motors and jet ski applications (mainly because two stroke pollution restrictions didn't hit those areas until later on).

Four stroke engines now rule those areas also -- and I was amazed to go into my fishing store and find out 1) how small and powerful 4 stroke outboard engines had become and 2) how durn expensive even a trolling motor was now-a-days.

Sorry Bill, we are both 2 stroke dinosaurs now.  Even Klotz has to sell 4 stroke oil now to stay in business because there ain't no world for two stroke engines anywhere except maybe for chain saws and little bitty air plane engines (and 4 stroke engines are showing up there now too in the larger engine sizes).

EPA drove it to get it started, but engineering development will finish it.  

Count the power strokes to see how it is all developing.  An H2 Kawasaki triple red lined at 6,800 rpm and counted out 3,400 power strokes in a minute on each cylinder, or a total of 10,200 power pulses per minute.  An SV650 red lines at 11,500 rpm and counts out 2,875 more efficient power strokes per cylinder, or a total of 5,750 power pulses per minute which is enough to give it H-2 parity at 100 fewer ccs displacement.   4 stroke pulses are simply more powerful than two stroke pulses.
(sorry Bill, they are)


But an SV650 is an older twin cylinder design now-a-days.

Consider a totally modern 599cc modern 4 stroke design which has 4 cylinders and turns up to 16,500 rpm at red line.  The math is easy anyway, 16,500 power strokes in a minute as the little beasties are even pulse tuned now to fire one cylinder per crank revolution to keep the rear tire being evenly driven at all times (racing traction being the only limiter that people even pay attention to any more since hp went well over 100 hp a while ago and they started having to tune for traction rather than peak HP)   Read your bike magazines, computerized traction control is all the rage as they can't ever use the hp that is already there without pulling big power wheelies at 150 mph.

Bill, that's well over your 100 hp magic number, already done been here for a while now readily available at any BMW, HONDA, Kawasaki or Yammaha dealership at 0% financing right now as we speak.   At less cc to boot, just to rub a little salt into the poor old two stroke's wounds.

Two strokes are dead for a reason -- they are no longer competitive.   And EPA loves them not, so they will stay dead going out into the future.

Even Klotz thinks so ....   they gotta try to make that transition into being "the 4 stroke super oil" if they can.    Maybe they can, but it's up to what Verslagen finds out when he puts it in his high performance skeeter fogger later on this summer as to whether Klotz is the Savage Super Oil or not.

Good point about them race tuned 2 stroke snowmobiles at 200 hp.  

What is the displacement of those puppies so I can select me an equivalent displacement 4 stroke race bike?  I gots me so many to pick from, some with turbos and such at over 500 hp but I gots to limit myself to getting as close to equivalent cylinders and displacement and such (or less) just to make the salt smart more.

Or, I could just wait a bit and let someone put together a turbocharged or blown race tuned Yamaha snowmobile .....

http://www.snowmobile.com/manufacturers/yamaha/2010-yamaha-nytro-rtx-se-revie...


   


I can't believe them folks complaining about the 4 stroke pulling too many power wheelies in the turns "lifting the skis" too much !!    They need some of that motorcycle style computerized traction control technology on them modern snow sickles.