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vibration

Singles without counterbalance mechanisms will always vibrate. A saw engine has nothing to counteract the momentum of the crank flyweight at 90 deg. btdc/atdc.
 
Singles without counterbalance mechanisms will always vibrate.
Thats correct and is the reason cranks are tuned to vibrate at a rpm level the saw doesnt use much. BTW TZ, You remember the Ducati super mono? That was single cylinder without a counter balancer that had perfect primary balance.
 
Ben, I've got to call you on that one.  "Perfect primary balance" and "single cylinder engine" are antonymous phrases.  I don't recall ever hearing of the Ducati Supermono before, but a little googling goes a long way.

http://www.sigmaperformance.com/racer_road_8.htm gives us this information:

"The engine is one cylinder off an 888 V-Twin bored and stroked to 572cc.  Both con-rods are still present; the 'vertical' cylinder and head have been removed and replaced by a pivoted balance weight.  The engine uses standard 916/996 Corsa components."

That sounds rather like a 90<sup>o</sup> v-twin, which as we all know does possess perfect primary balance.&nbsp; The fact that it's only using one cylinder does indeed make it a single cylinder engine, and you're correct about it not having a separate harmonizing balancer mechanism (which masks vibrations to some extent but does not produce perfect primary balance), but you're really stretching for this one.

Glen
 
The supermono uses two con rods on a 90 degree v twin crank. One rod is connected to a piston and the other is connected to a forked rod. Techicaly it is a single cylinder engine, but it as from a crank standpoint a v twin. Cool motor non the less.
 
How come none of the members here that actually modify saws
for a living ever make a post on these type of threads?

Maybe their boots are not tall enough.
 
Just checking in. I have to give someone hell, my wife went to her mother's house tonight, so I have to pick on someone.
She may be back in a few days, emphasis on "May".
I have just been lured to a neighbor's party tonight, it is in
walking distance, so the worse case scenario is a PI or at the
worst, reckless homicide, but no motor vehicle violations.
 
You guys are trashing this tread with your foolishness. BWALKER you should be out practising jug reaming not emptying. FISH, I think your wife is probably a good judge of character! Happy New Years All.

Frank
 
You're right! I am scum for trashing this fine thread of
regurgitated saw modifying knowledge, but that is my station
in life, haranguing, or at least harassing those with more
knowledge than myself.
Forgive me. I feel ashamed. I resolve in the New Year to not
give anyone a hard time ever again.
I always feel contrite the morning after reaming a big jug the
night before.
Forgive me............ Please......
 
Supermono

I remember the S-mono BW, very cool bike and very high dollar. Still had a rocking couple though, the rear "cylinder" not being in the same plane as the front.
 
TZ Also the super monos design basicaly is acounterbalanced design. The second rid drives a bob weight so basicaly its a counterbalancer. BTW I saw a supermono at Grattan once. The thing sounded bad.
 
counting

Actually I was counting. Can you please tell me how you arrived at the "3" figure?
 
If the Ducati started with 2 cylinders and lost 1 it would have 1 cylinder left.
The Honda started with 1 and added 3 making a total of four.

Unless of course you are implying that Honda started with nothing.
Then they wouldn't be gaining four they would be getting four.

Here we go again back to semantics.
 
cylinder count

Honda's test mule engines for the NR500 were singles, but the NR500 was always a four cylinder. The NR500 existed to circumvent the FIM rule limiting 500cc Gran Prix motorcycles to no more than four cylinders. To get the four stroke to pump as much air as a two-stroke Honda made the bores oval, with eight valves per cylinder. This was in effect a V8. To get the engine to pump enough air, it reached its power peak at ~22,000 RPM. Honda started with four (the rule) and ended up with eight (the solution).;)
 
xander,

I think you're missing something.&nbsp; The Honda engine did indeed start with nothing.&nbsp; They had cleaned up in the 60's racing a 250cc 6-cylinder inline four stroke motorcyle.&nbsp; They took a hiatus from racing and when they decided to get back into it, two stroke engines had become the standard fare.&nbsp; Honda said "well, we'll just see about that" and developed a 500cc v-four four stroke engine which spun at 24,000 rpm (or so).&nbsp; It had oval cylinders with four each intake and exhaust valves, two spark plugs, and the pistons had two connecting rods each.

Four cylinders was the limit and Honda had what was effectively an eight cylinder engine.&nbsp; I remember at the time that one of the tuners or so was asked a question at a press conference regarding one of the cylinder-pair banks, and he sought clarification by asking "which four?".

I bought a new model motocycle with an untested engine design because it was basically based on that endeavor.&nbsp; That was the V45 Sabre.&nbsp; I didn't like the way the head would start to shake at about 130mph, nor the final drive or ergonomics of the layout.&nbsp; When they again pushed the limits of the rules the next year by making a purpose-built race bike, the Interceptor, I traded for it even though I thought it was ugly; but it had all the changes made exactly as I'd envisioned they should be.

Glen
 

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