Low Speed Twisting Torque
by Gary Gregory
(Allentown nj us)
There's no doubting the fact that a four stroke engine produces huge amounts of twisting power over what a two stroke is capable of at the same rpm. I personally owned a 94 cr500. That particular engine needed help. I don't think Honda was thinking horsepower when they designed that engine. I could turn faster lap times on a two stroke 250 than my cr500.
I had learned that porting and piping an open class engine with a powerband somewhere between a 125 and 250, the sheer weight of the reciprocating mass of the piston would be the limiting factor. A speed shop in California told me that.
The only open class two stroke I rode that had any real low to mid power was a cr480. That engine had what I expected from my 500! So as it goes, my 500 was used as a play bike/pit bike. I got very tired of reading these stories of the 94 cr500r being scary because I just didn't have that experience. Maybe I had the kind of aggressive, brave riding attitude and wasn't scared of the thing?
Point being, I rode a four stroke Suzuki 250 and was amazed at the low speed acceleration. It was pulling hard off idle and I did less shifting, I'm guessing my 500 couldn't hold a match to the Suzuki at those rpms. But if you were like me when the 500 hit the market, the 500cc two strokes were much more fun to ride.
4 strokes have come a long way towards performance but there's nothing like keeping a 2 stroke spinning near its design speed. I think 2 strokes are capable of more max horsepower than a similar sized 4 stroke engine. I've always dreamed of an open class two stroke running on glow plug fuel (that stuff the small rc car engines use) at 60 - 70 percent nitro. You want to talk about scary?? I'm in, someone just has to build one.