If the weather is really hot you might want to try mineral oil to quiet the engine noises if they annoy you. While ok in the heat, synth thins out and I find my engine runs much quieter with dino. In the fall I switch back to synth for the cold fall and spring.

 

ALWAYS run H D dino the first 5k then switch to AMSOIL I like to make sure everthing seated properly and think it takes 5k to achieve this My.02

 

Hmmm... so how do you account for CVO models and many automotive engines that come with syn from the factory? I guess nothing ever gets "seated" in those engines?

 

To answer your question the M8 top end doesn't clatter like the TC did with synthetic oil.

 

IKR .
I went to Syn 3 at the first service and seems to run a little cooler and freer, I ran my bike in fairly hard though.The M8 is a noisy engine I spose as the pipes are way quiet , there's whirring and whooshing noises along with the regular primary noise , the quiet pipes make it so. They have to go.
Syn 3 isn't fully synthetic though is it . I went to it because of that just in case it was too early sort of thing , like a transitional oil.I know that makes no sense at all but I'm happy with that.
I will use a full synthetic at my next service.

 

I went with SYN3 at 1000 service and never thought twice about it. It did not make a difference in the engine noise. I don't short shift the M8 and the top end noise has never caused me to take it easy on the engine or be distracted by it. My 15 Heritage TC 103 with Syn3 was a different story. I think that is why the M8's speed kinda creeps up on you fast cause the engine doesn't sound like it's working hard unlike my former TC 103. When I put ear plugs in with my 103 and I tended to ride it much more aggressively.

 

Doesn’t matter what oil you use because it will end up sumping and destroying your bike anyways.

 

It sounds like some are worried about break in oil. These engines are bench run long before they ever see themselves in a chassis so I would think you could change over to syn oil anytime you see fit.

 

OP run what you like! The clatter rattle of the modern vintage HD engine is what it is. If you have a M8 that sounds like a sewing machine great! If you have one that sounds like a coffee can full of rocks so be it. Oil is not going to change that over all characteristic. Mine sounds like a coffee can full of rocks. A buddy of mines sounds like a sewing machine. Hes used different oils and so have I. I always go back to Amsoil. He uses whatever is on sale at China-Mart or at a auto parts store.

Big thing is,,, change it and the filter. And if you have a self changing tranny change all three holes at the same time.

Good Luck

 

Good advice...... and if you DO suffer from the dreaded hide-n-seek transmission fluid, don't put any fluid in your tranny that you DON'T want in your primary........ cause that's where it'll end up.