Motorcycle Repair: engine misfire, honda spada, air fuel mixture

Question
Mark  My son has recently acquired a Honda Spada (1989 VT250).  It runs very well up 'til 8000 rpm and then starts to miss 'til 10500 rpm where it runs very well again to the redline.  Checked wiring with multi meter and all seems fine.  I am thinking it could be the CDI unit.  The bike has done 26000 km and there is very little info on the net.  Problem does not seem to be fuelling.

Answer
Hi Peter,

I suspect an air-fuel mixture tuning problem.

Please include your email address as requested and explained in my instructions. I return tech information files by email. I'll return carb tuning files and CDI test information, too.

Instead of engine speed, can you decribe what throttle opening positions the problem occurs?

The carburetor is tuned with respect to throttle positions. RPM is helpful for fine tuning.

Respectfully,
Mark Shively