So it looks like the figure of 20hp that is published, posted and discussed everywhere is very much a 'claimed' figure from Yamaha. Typical. I have never seen an SR reach that in a test. The highest I have seen is actually one of these Spanish ones above - where they got 16hp (yes, at the wheel). But still, most have shown a rear wheel hp figure of 13 something with a crank/flywheel power of 17-18hp.
Torque seems to be quoted at between 1.4 to 1.7kgm which is 13.7 to 16.7Nm. This is similar to the Australian and Which Bike tests which got a figure of 12.3Nm.
Interestingly, with one of these Spanish tests, they obtained a rear wheel figure and a crank/flywheel figure so you can calculate the power train loss into a percentage. I will use this to calculate the flywheel power after my own tests.
So from 18.2hp at the flywheel, to 13.6hp at the wheel, a loss of 34% has occurred. Is this correct? 13.6 x 1.34 = 18.22
There is one other factor to come into play here and that is the metric horse power vs the imperial horse power - which is perhaps what Yamaha would have used in any promotional material. A metric horse power is 98.6% of an imperial horsepower - not much, but would add up.
Anyway, the output perhaps depended a lot on the specific year model and the country to receive that model.
Torque seems to be quoted at between 1.4 to 1.7kgm which is 13.7 to 16.7Nm. This is similar to the Australian and Which Bike tests which got a figure of 12.3Nm.
Interestingly, with one of these Spanish tests, they obtained a rear wheel figure and a crank/flywheel figure so you can calculate the power train loss into a percentage. I will use this to calculate the flywheel power after my own tests.
So from 18.2hp at the flywheel, to 13.6hp at the wheel, a loss of 34% has occurred. Is this correct? 13.6 x 1.34 = 18.22
There is one other factor to come into play here and that is the metric horse power vs the imperial horse power - which is perhaps what Yamaha would have used in any promotional material. A metric horse power is 98.6% of an imperial horsepower - not much, but would add up.
Anyway, the output perhaps depended a lot on the specific year model and the country to receive that model.