You can run the same in all 3, be it AMSOIL or M1, butwhy?

Put a good 20/15W-50 SYN in the engine (I use M1 VT currently, but will switch to M! 15W-50 next time, pretty much the same oil, fewer $$)
Put a SYN tranny oil in the gearcase, 75W-90 or 75W-140 if it's loose or noisy (I use M1 75W-90 and have no reason to switch)
Put a good DINO 10W-40 in the Primary, using SYN there is a waste (I use Shell Rotella)

 

They either can't accept change, or want more of your money.

Syn is better in a car (water cooled) motor, it lasts longer. In an air cooled motor, it is exceptionally better. If the air cooled motor gets hot, it will break down conventional oil at a much lower temperature, subjecting your motor to virtually no protection for the next 1,000, 1,500 or 2,500 miles until you change the oil. It's not even a reasonable question - with an air cooled motor, where heat can spike for a short period of time (think NJ shore traffice or a parade in August) it's Synthetic.

I have a Nissan Pathfinder. Mobil 1 every 5,000 miles since new. Has 150,000 miles on it - no engine work, period. Runs like it was new. The question is which syn (and I'd tell you Amsoil and Mobil 1 are both awesome) not if syn.

 

Baby Oil in the primary, Tractor Hydraulic Grease in the tranny and a diluted concentrate of brylcream and water for the engine....

 

Syn3 is made by Citgo and sold by HD. Why would you allow Hugo Chavez to profit from your choice of motorcycle oils? That alone is reason enough not to use Syn3 IMHO.

I use Amsoil 20W-50 in engine and primary, and 75W-90 in tranny.

 

AMSOIL in all 3 holes & K&N Oil Filter (Most User Friendly Filter for the HD)!!!

 

They're all shoveling you a load of crap. Synthetic oil will prolong engine life. SYN3 will be noisier in your tranny. I have used SYN3 since the beginning but am changing over to Amsoils which is a better product. Synthetic oil is a no-brainer.

 

Mobil 1 V-Twin 20W-50 Engine and primary
Amsoil Severe Gear 75W-90 in the transmission
Mobil 1 and Amsoil are both great oils.

 

Amsoil all three holes.[sm=shades.gif]

 

So, when (miles) is it OK to switch to synthetic in the engine and transmission? On BMWs the conventional wisdom is to wait until 10 to 20 K miles for the engine. I don't know about the transmission. With respect to the engine, the concern is that switching too early will not allow the rings to seat properly and result in excessive oil consumption over the life of the bike.

 

I'll help. Harley-Davidson does NOT make oil. They, like all other vehicle manufacturers out there, put out a bid for an oil to be supplied that meets certain specs. Once a winning bid is accepted(usually the lowest bidder ) they supply them with H-D labels, and then mark that oil up substantially to the customer. You can find a much better oil for the same, or lower, price. AMSOIL will do you much better