73mm piston?

[crazyxr250rider]

Hey guys I dont know how to work out how many cc my bike is know with the 73mm piston in.

[scumdog]

Hey guys I dont know how to work out how many cc my bike is know with the 73mm piston in.

Wot's the stroke? ya need to know that too, of course that is assuming said 73mm piston is just not hanging from the handle-bars!!

(73MM? haven't seen a piston that small for a long time!?)

[vifferman]

(73MM? haven't seen a piston that small for a long time!?)
I spoze all your vehicles' pistons are measured in feet, or fractions thereof.:blink:

[scumdog]

I spoze all your vehicles' pistons are measured in feet, or fractions thereof.:blink:

No silly, I had a car once that had the brake cylinder that size!!

[crazyxr250rider]

according to a statistics site 73mm is stock and that my bike is 29odd horse power however I very much doubt it more like 19 horse power with the wiesco piston (by the way thats was I got)

[Motu]

Um...if 73mm is stock then it will have stock capacity - how many cc is your bike stock?

[F5 Dave]

pi x D squared over 4 times the stroke. Divide by 1000 to get cc

ie: (bore x bore in mm) times 3.14. Divide by 4 = #
then times stroke/1000

easy

example for 70mm bore & say 65mm stroke (guess) would = 250cc

[dickytoo]

according to the wiseco cattle dog, 73 mm gives you a capacity of 249 and if you take it up to 78mm you'd get about 280 cc.

[crazyxr250rider]

Sorry guys I read the job invoice wrong. The bit that says "has 73mm piston"is the job log.That means that my bike will have the next size up.