Poor mid-rev. performance

[Pysen]

Just bought this NSR from a friend that really made a poor bargain when he bought it 3 years ago. He have bought a new cylinder and piston but the problem remains so he gave up and sold it to me. The engine should be 31 BHp according to the original papers bot it doesn't.

The bike is an -89 and is having really poor torque at medium engine speeds. In fact I find it hard to accelerate at all from 50 mph on the 6th gear. I guess I can get it up to 70 mph if I really rev it hard (above 10000 rpm).

I would really like to have technical opinions about this before I try to tear it apart.
I certainly don't need comments from self-styled "grandmasters of wit & humour".

[Robby]

well its a 2 stroke, so you should rarely let it below 10,000 rpm.

is it fully derestricted?

what country is it from?

[khavell]

[Kickstart]

Hi

I would check the power valve is working properly, that the exhaust isn't too coked up and that the air filter is clean. After that try a compression check (will reveal piston / ring wear) and check the igntion timing (should be fixed, but the woodruff keys that hold the rotor in place can shear off)

All the best

Keith
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[one1895]

You sure this isn't just normal? I find I have to drop it down a gear or two to make it accelerate faster up to the 80mph mark?

Cam.
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