SV650 wimpiness

I thought my SV was a little sick, but it took till today to find out just how bad it was.

I swapped bikes with another SV rider and went for a spin. The immediate conclusion - my bike is missing at least 50% and probably closer to 2/3 of the power it should have. I went 100 miles per hour on a motorcycle for the first time today and that happened practically instantaneously from freeway speed.

Compared to the known-healthy bike, my bike pulled just fine up to 4500-5000 RPM and then just got badly winded while the strong bike took off like a rocketship. The strong bike also had massive engine braking compared to mine - when I lifted off it locked the back tire for a couple feet while mine just coasts.

Carb jetting on mine appears to be right; both the local bike shop and I have gone through the carbs.

Can anything other than "severe lack of compression" explain this?

ign timming to retarded can cause some of it but 1st thought was lack of compresion or tight valve lash.

These engines DO tighten their valve lash over time. When did you just adjust them?

Came here to recommend a valve adjustment. Good work guys.

Also, do the engines run basically the same audibly? For instance, I was chasing an intermittent loss of power around on my TL for a while until I figured out one of the coils was cracked and occasionally shorting to ground, effectively dropping a cylinder sometimes. (Of course I'm too cheap to just buy a coil, so I used the ol' Aqua Net fix for a while.) If yours runs rough or the sound/fell of the motor changes, you may want to look at the ignition system, if you're convinced your carbs are in good shape.

But definitely check the valves first. That's a really likely culprit.