Posts
191
Joined
1/15/2012
Location
Washington, IA
US
Edited Date/Time
2/18/2020 3:15pm
I have way too many but 2 of them have this ground out spot on the exhaust exit. Rt hand side sitting in the seat. This one is a pro circuit ported east coast supercross bike. I did not know if it was flow evening grind job or not. Or just a year over year thing.
The Shop
Abrupt transitions on airflow are never good. Rule of thumb to keep separation from occuring at the walls (boundary layer) is 7 degrees or less. There is some wiggle room around that depending on how pressure and temperature are changing but that rule works in most cases. A drop is better than a lip in transitions from part to part but if you can make it smooth it should be even better. Anytime I do a crank I always gasket match parts and clean up casting marks, the motor always seems to run better and jet cleaner after that.
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