Going to be taking in my 08 Classic in a few days to have everything changed and serviced. I plan on taking in Amsoil 20/50 for the engine and primary and take in a qt of 80/90 Amsoil severe gear lub for the transmission. What are your thoughts on going to synthetic at 1,000? I did not see a problem since the screaming eagles come out of the box with full synthetic. I have heard stories about waiting until the valves and rings have seated before changing. I guess I do not see how systetic oil would slow down or stop seating. My goal is to help the engine run cooler and quite the shifting noise in the transmission. I did install a Jag vertical cooler when I bought the bike and wow what a difference that made in heat.

 

I switched to synthetic a while backand haven't had any problems. As far as I'm concerned it's the way to go.

 

I'm at 850 miles and am planning to do the same thing at 1000. I'm going with the oil in all 3 compartments. I deal the stuff but still have been debating on which way to go. Took a look at the kinematic viscosities of each of the gear lubes and the oil and compared. The oil and the 75W-110 are comparable at 20.1 and 20.4cSp respectively. The 75W-90severe gear lube is at 16.7. If you're looking at the 80W-90, product code AGL, it is at 14.9, so it is the "lighter" of all of them.
Just some numbers FYI.

 

Not sure if there is a way to edit posts, but can't find it. To clarify above, these KV's were at 100C. The severe gear lubes and the oil also pass the ASTM-D892 foaming test with no problems. All have viscosity indexes greater than 150, the gear lubes are a little higher.

 

I switched to syn3 at 1k, them Amsoil at 5k and installed a jagg vertical cooler by 10k, and am approaching 30k with no problems on my '07 dyna. I run amsoil 20-50 in all three holes because it's easier to just keep a case of one kind of lube around.