Twin Syn

[JRay’07]

While browsing the Isles for M/C oils I noticed that there are products marketed for v-twins but not parallel-twins. Why would this cylinder configuration require a custom tailored lubricant? Making the distinction between air and liquid cooling would be more important.

 

[Jetronic]

aren't the V-twin they refer to using a dry clutch?

 

[ragtoplvr]

the V twin Harley has some unique features that can benefit from special additives. roller and ball bearing crank. Much hotter rear cylinder hydraulic lifters.

 

[JRay’07]

aren't the V-twin they refer to using a dry clutch?

That’s a possibility on some older bikes (excluding Harley Davidson).

 

[EvoMan]

aren't the V-twin they refer to using a dry clutch?

Harley’s are V-Twin and have a wet clutch. If you look on the front of a bottle of Mobil 1 V-twin, it shows for use in the engine, primary and transmission. On the back it says recommended by Exxon Mobil for use in Harley Davidson.

 

[Bonz]

Mobil 1 20w50 V-Twin (or any "V-Twin" marketed oil), for example, has nothing in it that would make it unsuitable for a wet clutch. Used it with great success and held grade in my inline 4 ZRX1200 with engine/cam/carb/exhaust upgrades (i.e. 145 hp/87lb-ft) on a 5,000 mile OCI. Gets hot on engine/oil temps at elevation in Colorado when going through any town or stop and go. Redline 20w50 dipped a bit in grade over 5,000 miles and currently SuperTech 20w50 V-Twin just went in to replace the Amsoil 20w50 V-Twin that went 5,360 miles. None of them lost shift feel and looking forward to posting the Amsoil 20w50 (got it from Pablo on this forum) analysis when Blackstone gets it done.

20w50 as a whole is more appropriate (for V-Twins and/or old air cooled Classic UJM's) given the temps air/oil cooled engines see during the riding season. I use 20w50 in the ZRX because the oil pressure at idle on the ZRX and that whole family of Kawasaki engines that spans decades has known low oil pressure when hot if running the recommended 10w40, despite liquid cooling.

EvoMan, The Harley clutch is bathed in oil, however it is not a shared sump with the engine oil which is what most folks think of as a wet clutch. That would be a distinction to note, IMO.

 

[Japanese]

To add to Bonz info. Most (if not all, except V-Rod) V-Twins are air/oil cooled and run hotter than other engines, especially their rear cylinder. They have higher tolerances between their internals (bearings, pistons) to have room to expand when hot. For that reason they need higher viscosity oil like 20W50.
Not all parallel twins are air/oil cooled and if some are, they don't have the same cooling and expanding characteristics as V-Twin engines, that have push-rod valvee trains, where parallel twins usually have over head cams.
I also think for cooling purposes Harley Davidson specifically have different oils in the engine and the gears. Sometimes (I think, but not sure) they run three different oils - engine, gears, and primary case (clutch). That is designed for optimum lubrication at high temperatures.

 

[repairman54]

My Road King has 3 oil holes. I run M1 in the engine, Redline in the primary and Redline Heavy Shockproof gear oil in the trans.
I'm no fan of a fits all holes oil in a HD. V twin rear cylinder always has run hotter than the front due to less air flow. I remember reading somewhere about gears in a trans. shearing oil faster than just lubing plain bearings.
They still make a parade kit to cool the rear cylinder in the big twins.
No cooling issues with my old inline Hondas, twins or fours. All the cylinders get equal airflow.

 

[BigCahuna]

I understand Harley's reason for recommending one oil for everything, but even they have not stuck to their theory about it over the years. Harley engine's being what they are use mostly roller bearings, which don't require high oil pressure to live a long life.Only the wrist pins and rocker boxes use bearings most similar to car bearings. Their transmission are full of gears, and have a splash to get lubricated type of system. I myself use automotive gear oil, as that is the only thing that gets lubricated by that oil. Recently Harley has decided that that's a good way to do it, and have come out with their own brand of oil for the trans. Being the trans doesn't get the same contaminants as their engine oil does, and their engine oil only can meet a GL-1 rating as far as gear oils go. And comes out looking like new oil. It will work, but there are better oils to choose from. In the primary, you can use their engine oil for lubricating the primary chain, tensioner, and for cooling the clutch pack. Or pretty much any type of cheaper 10/40 or 15/40 wt oils. The primary doesn't need anything special. The only reason that oil gets dirty, is from clutch dust that gets mixed in there. Never seems to create any issues. All the oils will help keep parts sliding along and cooler then not having oil in them. People slam Harleys oil for being nothing special, but dealerships sell and use a ton of it in a years time. And it does work as advertised in customers bikes. I've said it before and still say it, any oil is better than no oil.,,