I ran Amsoil 20w-50 in all three holes in my 2012 Street Glide from 1,000 miles to the 5,000 mile service. Oil was brown like normal wear after 4,000 miles. Had factory Dino oil in it prior to 1,000 miles.
First thing I noticed was how noisy, lifter noise and rattle, the bike ran on Amsoil. Read the threads and saw that the increased noise was somewhat normal. Changed to Mobil 1 20W-50 V-Twin, Redline Primary Oil and Redline Transmission Oil with Shockproof at 5,000 mile service. Immediately noticed less lifter noise and felt smoother especially at higher rpm. HUGE......repeat...HUGE improvement in transmission performance. Smooth, easy shifts and a lot less "whine".
Of all HD dealers and indy's I've spoken with face to face, at least 90% recommend Mobil 1. But when it comes to transmission lubricants, the HD dealers I've spoken to seem "clueless" on the real benefits of a good gear oil.
Personally, IMO, I see no added benefit of running Amsoil over Mobil 1. When it comes to cost, Mobil 1 at half the cost of Amsoil, and availability, Mobil 1 wins.....no comparison. JMHO.
Roger That

 

I was a loyal user of Amsoil for years in my cars & trucks but found that Mobil 1 does the same job, is cheaper and easier to find locally. In my bikes I also switched to Mobil 1 because I found it dampened the top end noise more then the Amsoil.

Not knocking Amsoil, just stating my personal experience with it and Mobil 1.

 

OP said the lifters were loud and the oil was black and thin. Black is from carbon. Carbon is from insufficient fuel burn. Thin is from the synthetic oil picking up simple carbon molecules (smaller than the oils hydro carbon long chain synthetic molecules). The long chain oil molecules can't adhere to each other (become longer or larger) because they are covered by the simple carbon. This makes the oil appear to be thiner. The base oil viscosity has not really changed and thats why there was no signs of damage. Loud is from "thin oil".

Amsoil does not produce or manufacture anything. They just blend stuff together. This need for the base oils and all the other different additives they blend to be able to accept and be compatible to each other also makes the oil susceptible to the process described above.

Amsoil and other batch synthetics are great in controlled tight tolerance (laboratory) conditions / applications. Thats where they were created, to meet a specific condition. They are an engineered smart oil. That big air compressor under your seat is far to crude, and has too many environmental and operating variables to be able to use such a specifically designed oil in my opinion.

If you run a stock engine, using Harley stock mineral oil and changing it out often is probably your best bet. The containments in all the air that gets pumped through that thing is the biggest risk. Mineral oils have natural "detergents" or surfactants that basically load with carbon and other contaminants and break from the oil molecule, clumping together and depositing in your filter or oil pan. Some synthetics just hold on to this stuff.

 

Amsoil for me. I run it in all of my vehicles, diesel trucks, pickups, cars and motorcycles. Tens and tens of thousands of miles, no problems at all. If you want it and can't find it, send me a message and I'll direct you to my website and you can order away.

 

Have run Amsoil for 45000 miles in my 01 Ultra with no problems. Run it in my 02 Monte Carlo also as well as Amsoil transmission fluid and have 273000 miles on it without any problems ( daughter still driving it), have 149000 0n my 07 Nissan with it and 189000 on my F-250 Diesel with Amsoil Trans fluid as well. Will continue to run it til something i own develops a major problem due to Amsoil, until then, i'm a believer.

 

This is likely the stupidest statement I have ever heard.

 

Same here. After building my motor with s&s parts I read that they used to recommend Mobil1 for their motors, so I tried it and never turned back. I still use their sever gear 90w in the trans though.

 

I could basically say the same thing about Valvoline Dino oil. It's my choice as best of that class, after much reading. I'm running it this winter instead of syn to try to raise the temps a little, if at all - often I can't get enough heat even running crash bar chaps. That's bad for mileage and not great for the engine oil either. (acid formation, water retention)

 

Sounds like Amsoil 5w20 was used in a Harley

 

Wow. I though i was being cheap using Mobil1, but will sleep a little better after not searching for Amsoil. Mobil1 c an be had almost anywhere including WallyMart.

I will continue to use BelRay in the tranny; less whine and clunk!