Flush? Sounds like a bad idea..
ENGINE FLUSHES:
If you have a wet-clutch on your motorcycle, you need to remove the clutch pack before using any engine flush (such as Gunk "5 Minute Engine Flush"). If you have a dry clutch, this is not an issue, and we recommend using this flush if you notice any varnish on your engine internals or sludge deposits in your oil (especially as you change it). Changing your oil more frequently, and using a good grade of oil will help keep you from needing to use an engine flush product.
NOTE: Some motorcycle engines have oil coolers and other reservoir areas retain oil during a typical oil change (example: Bandit and GSXF engines retain up to 35% of the oil between the tranny, oil cooler and upper engine); when you do an oil flush on such an engine, you need to drain the cooler after wards and do two oil changes in short succession to each other (with 5 to 10 minutes of engine run-time between the oil changes). This will net you about 95% of the oil being renewed and guarantee enough of the oil flush product has been cleared out. If doing this, change your oil filter at the time of the final oil change.
taken from this site
Understand Motorcycle Oil @ MotorCycleAnchor.COM