Virago 250 pistons are small: 49mm (less than 2 inches) wide
I have lightened my Virago 250 a little, it weighs about the same as the bike I drove when I was 16 – a Honda CB-160. The Virago is a long stroke engine, and its pistons are almost the same size as the CB-160 pistons.
This is the bike I drove when I was 16.
The CB-160 was a very popular lightweight bike in the 1960’s (it might have been the most popular – I’m not sure). In my hometown ( Okeechobee, FL), the CB-160 was considered to be a bigger bike than it would be today. A lot of young people drove Honda Sport 50’s, 90’s, and Super 90’s.
Since I weigh a lot more than when I was 16, my Virago 250 is not much faster than my CB-160 (only about 10% faster).
bike, full tank +rider hp hp/lb
Virago 250 522.5 lbs 22 0.0421 (1)
CB-160 431 lbs 16.5 0.0383
(1) power -to-weight ratio is 10.0% higher than CB-160
my XV250 278 lbs dry /// 312.5 lbs wet (2)
CB160 282 lbs dry /// 301 lbs wet
(2) note: I had reduced the weight on my XV250 by about 25 lbs at this point
Horsepower comparisons are mis-leading, the long stroke Virago 250 has relatively more mid-range torque than the CB-160.
Virago 250 22 hp @ 7500RPM /// Torque 15.2 ft-lbs @ 6000 rpm
CB160 16.5 hp/10,000 /// Torque: 9 ft lb @ 8,500 rpm
If the Virago 250 was a vertical twin similar to the CB-160, it would have about 13.9 ft-lbs @ 8,500 rpm.
Very good mid-range torque is the reason that a Virago 250 accelerates a little stronger than you might expect.
On a CB-160, 60 mph was 7,100 rpm (approx), 70 mph was 8,200 rpm, top speed for a good-running one was 85 mph which was 10,000 rpm, in my hometown Johnny S. had one (completely stock) that would do 102 mph which was 12,000 rpm. At 14,000 miles it blew up, and after Johnny rebuilt it, it had the same top speed as any other CB-160 (82 to 85 mph).
On my Virago 250 (sprockets not stock), 60 mph is 5,100 rpm, 70 mph is 6,000 rpm, and top speed on level ground is at least 85 mph which is 7,300 rpm. -Les S.