In all my years of riding some truly antique motorcycles,have never flushed one.It is your call.

 

I would just put any good but cheap 10w 30w oil in and drive just long enough to warm it up and then change to a syn oil. I have used a product that cleans the sump in cars before, but I would not use it in a bike.

 

Don't know about flushing or flush kits but, in the cooler season, I run 15w40 Rotella Deisel grade oil. Engine oil designed for Deisel are said to have more detergents than other engine oils ( holds up better in high heat and carry more load too,they claim). Seems to keep all my engines clean inside.

 

why, cause amsoil is so awesome that it doesn't get contaminated from use? doesn't matter what you use, the oil is gonna get dirty. dude just wants to make sure that he gets all the old, dirty oil out. you, on the other hand, don't care about that last little bit of dirty amsoil that you are leaving behind. your call.

 

+1 you can get 15w40 Rotella at WalMart for $10.50/gallon...and it does have a lot of detergent. Run it 1500 miles and drain hot...change the filter. Do this 2-3 times and your engine will clean up nice.

 

Most all of the syn oils keep an engine cleaner than dino not just Amsoil. This is because of the fact that they do not oxidize as rapidly as dino oils. Dino oils typically oxidize at about 250*F which is a temp most HD engines routinely hit. Synthetic oils won't oxidize until well over 300*F which is temp most HD engines don't hit. This resistance to heat is probably the main reason syn oils are best for an air cooled engine application. However, Amsoil is pretty good stuff. I use Redline and LAT and Mobil1 but Amsoil is by far excellent.

 

I would not add any thing to your oil. If want want to clean up your block, a good ester based motorcycle oil will do that (Motul, redline, there are others). Esters have a high degree of solvency and will clean up a motor. That is all I would do. Dirty oil does not mean a dirty engine but if you're concerned, use ester oils. Run a good 3k miles on the oil and you'll be fine.

 

Run a quality oil and change it regularly. That's it.

 

I have been working on engines for 25 years, like the last post change your oil 3500 to 4000 miles and use a good filter, Your motor will stay spotless inside. Do not waste your money on flushes, they can do more harm than good under some circumstances.I have seen some additives that eat seals and gaskets, use a good oil and filter and change it often.

 

I think it is not needed, especially if you are using a good synthetic, but if I was concerned about it I think I would do the Seafoam and back to back oil change once every 10k miles or so rather then buy a purge kit.