I got a couple of cylinders and both have had some work done. Both have the exhaust cleaned up but 1 has 1 sleeve cut down (or up) to the divider and then it was kinda tear dropped only on the inside of the sleeve? I've seen that done before. So no matter what I'll have to resleeve the cylinder set so they'll match. Hopefully I can get some templates from Ericsson's? My wife isn't going to let me spend a ton change on it so I'll have to just get by or find someone who has to many parts and easy on the pockets..lol!!Pictures wont show important details. Remember that a 650 wont have as much low end so raising the exhaust port also requires raising compression. A zeeltronics ignition can help with response and lower the fuel requirement. I like to clean up transfers and widen the exhaust port to 66% of the bore and raise it no more than 190 degrees open. Bend the impeller so the pipe hits quick enough, this is important and it will end up flatter than you may expect. Top rpm should be close to 7000 depending on the pipe used. You can pump them up more by widening the exhaust more and upping compression but top end life will suffer. I know that a pair of Mikuni 44s will work, never tried anything larger.