Oil and large bore V-Twins...short 'n sweet...
...that to run a large displacement V-Twin engine format, calls for a thicker 20W50/60...is absolute B*** S***! Absolute B.S.!
I bought into it...many others have as well...oh...a 10W40 will shear in atmospheric temperatures of 80-100 F. Yeah...if you insist in buying bargain basement, 10W40 crap....probably...
....but if you put in Royal Purple, Redline, Amzoil... ( I run Royal Purple Max Cycle 10W40, personally), you will get better all-round lubrication and performance from your large bore V-Twin...whether it is a Yamaha SVTC, or a Harley and/or Indian.
I have noticed that the HOTTER, yes folks, the HOTTER outside temperature, this marvelous 113 cubic inch engine is travelling through, or even sitting in stop 'n go/red lights...I have found out that it (the transmission) shifts even easier, than at 68-75 F. It's even easier at that outside temperature, but all week, I have been running in 94 F with a humidity level that makes it 110 'real feel'...and the 113 never missed a beat...never even got hotter on the left side...and YES...I attribute this to the oil I have decided to run with...and stay with for the life and ownership of the bike. Running R.P. Max Cycle is seriously, like adding water jackets to the engine.
Their proprietary additive package called; Synerlec is ***absolutely*** no hype or B.S....for I am seeing the real world results and did see, not one mile after the installation of 6 quarts of Max Cycle 10W40 two months ago.
Bottom line...probably every every V-Twin owner, that for the last 15 years, bought the 20W50/60 kool-aid myth, that you MUST run a thicker oil, or burn up your engine... (did just that...bought the kool-aid) ,well...perhaps 30 years ago...but with today's high performance, premium ....PREMIUM, not Wal-mart or Dollar Store, mineral,...a 10W40 is the sweet spot.
I also have a theory why my 113 became so well mannered....is that a thicker viscosity oil...is actually being 'pushed' and moved around the tranny gears...and not necessarily making a 'bathed in oil' contact between gear teeth, et al. This is why I had tranny noise and growl, when putting the transmission under a heavy load running even Yamaha's 15W50. The minute I put in Royal Purple Max Cycle 10W40,...NO FURTHER sounds emanated from the tranny, and all I heard, was the shifter click to the higher or lower gear. My gears and shafts are bathing in oil...and not agitating it, like a boat propeller acting upon water.
20W50/60 is too thick...doesn't flow well through the oil galleries, travels slower for a full pass through the oil cooler...too slow returning from the valve heads...to the dry sump...too...slow...and that adds heat to your engine. Since swapping out, I feel no more heat coming from the engine, or the rear left side...even in the last few days of 110 F real feel.
You need to run a 20W50/60 oil in the United States South West... BULL! Absolute Bull... Bill...who lives in swamp-armpits south Florida...***YOU WERE SO RIGHT...RIGHT ON....YOU ADVISED THIS MONTHS AGO...about the Yamaha SVTC runs better with a high end, 10W40 formulation and Joe thanks you, very much for taking the time to post your observances...and yes...I mimicked all that you stated...like a mirror! Thanks Bill (American)...I have a superior running SVTC because you posted your observations regarding a high end 10W40, replacing a 15/20W50/60 installation. Thanks!
Is this a personal endorsement for running a top quality PREMIUM 10W40 Full **SYNTHETIC** in your SVTC, Harley, or Indian? You bet it is,....but this will be the last one...for you can lead a forum member to the water trough, but you can't make him/her drink...(and cool off....)! They have to drop their head into the water themselves...lol!
End of endorsement and personal experience ....
Last edited by YamahaParExcellence; 07-08-2019 at 03:06 PM.