front sprocket size + dyno run?

[Stu]

My bike is 8k revs at 100 so I guess I do have a 14T front sprocket as i thought. It's not a problem for me and still get at least 45 mpg.

As to how it affects a dyno run, I told the operator as I think he specifically asked.
But I don't understand what difference it makes. You should get the same max power at the same engine revs, it's just that the rear wheel & Dyno drum will be travelling at a different (slower) speed than the same bike with a 15T. But surely the dyno doesn't measure the top speed of the drum, but the acceleration & deceleration of the drum?

Originally Posted by Stu

But surely the dyno doesn't measure the top speed of the drum, but the acceleration & deceleration of the drum?

If you assume the throttle is opened/closed at the same speed, a 14T front sprocket would be an increase in acceleration, which is what the Dyno measures.

[Stu]

Originally Posted by Baph

If you assume the throttle is opened/closed at the same speed, a 14T front sprocket would be an increase in acceleration, which is what the Dyno measures.

Yeah but, No but.
A change to a 14 T cannot change the HP or torque of the engine or the revs at which max HP or torque is obtained.
(Next you'll be saying the R6 throttle tube gives you and extra 3 hp )
I think you just need to tell the operator to make sure the Dyno machine gives as close to a true reading as a Dyno machine can.

Originally Posted by Stu

Yeah but, No but.
A change to a 14 T cannot change the HP or torque of the engine or the revs at which max HP or torque is obtained.
(Next you'll be saying the R6 throttle tube gives you and extra 3 hp )
I think you just need to tell the operator to make sure the Dyno machine gives as close to a true reading as a Dyno machine can.

Or so he/she winds the throttle on a little slower to compensate?

[jambo]

Originally Posted by Stu

Yeah but, No but.
A change to a 14 T cannot change the HP or torque of the engine or the revs at which max HP or torque is obtained.

Correct. It will not change the power of the engine at all, and if you were using an engine dyno it'd be fine.

However, if the dyno measures the thrust at the rear wheel it will get different readings in say 1st & 3rd gear. As you're changing the gearing this may need to be taken into consideration.