The conversion from torque to horsepower is as follows.

(Torque (lbs-ft) X RPM) / 5252 = HP

Now considering the 150 engine is basically just a bored out 125 engine, the torque curve ought to remain the same, just bumped up a little higher all around. But with similar construction and the same stroke, the peak torque and peak power ought to occur at the same RPM as the smaller engine. It certainly is true with the peak power so logically peak torque should too be at 7500 RPM. So the most likely scenario is this creates a peak torque of 9.04 lbs-ft at 7500 RPM.

At 9.04 lbs-ft of torque 7500 RPM you've got 12.9 hp on tap. So extending this with the same ratio of torque to horsepower of the 125 to 8500 RPM, gives us a maximum theoretical HP of 13.92 at 8500 RPM with our 150cc engine. If the RPM limit were raised and this is a naturally higher revving engine than the 125, then further extending this ratio to 9000 RPM would give 14.73 HP. Awfully close to the rating claimed by SYM.

This is calculated using the torque number from the 150cc engine but using the more realistic peak torque RPM from the 125. Engines are rather predictable when it comes to output when changing displacement and the 150cc engine, if the measured torque is correct, actually fits inline with the output.

If you notice the 125cc puts out more than 100 hp per liter of engine, actually rather modest when it comes to higher revving engines, and perfectly inline with air cooled technology. I know my Suzuki GS500F had about a similar HP to displacement ratio, 47 HP and 487 CC displacement, air cooled carbed just like the Wolf. So in the same boat it's perfectly reasonable to expect 14.79 hp out of the Wolf's 150cc bike considering it's actually got less power to displacement than the 125cc wolf.

Honestly I think the published numbers are right except for the torque's RPM measurement, it really should be at 7500 RPM as that fits more inline with the engine design and actually makes all the numbers make sense.

And one problem you've got comparing acceleration with the HD200 is that a CVT and higher torque engine makes for much quicker takeoffs because I know the Buddy 125 can outpace the Wolf off the line until I enter the higher power band and can take advantage of the power. It's why those high revving Honda's just feel so weak even though they have very good HP numbers. If all the HP is up top, you're not going to be able to use it and feel it on a daily basis. But I can tell you one thing. Comparing this to my old Honda Rebel with 18.76 HP the top speed of the Wolf isn't that bad. Honestly I think the Honda Rebel topped out at 75 mph and I know my Wolf can just about get to 70. So I'm apt to believe the HP claims.

Just remember these HP numbers are measured at the crank.