I agree, I just think the 20/50 is too lite for the transmission. And you being the subject matter expert, I'm glad you spoke up.

I've been using the Mobile synthetic gear oil, 75/90 but I think next change I'm gonna try the 80/140.

 

While it would seem to make sense that engine oil is not the best for lubricating meshing gears, isn't the internal twin-gerotor oil pump design used in the TC essentially two gears meshing? This same design is used in practically all air-cooled pancake piston engines from Volkswagen and Porsche to aircraft engines? And, how about those aircraft engines with prop gear reduction...it is all internal and they use gears lubricated by the engine oil...also, the performance demands are much more extreme and an engine failure is a whole hell of a lot more disastrous than a motorcycle engine failing...yet they are very reliable and rarely fail...

 

Mark,

My father I'm law uses you 5 speed race trans, n1 drum, manual tensioner, & smaller comp. Killer, rock solid products. BTW he uses Spectro gear in trans no engine oil.

 

2010 EG 103" - 30k


Synthetic oil is made intentionally to be slippery. Not sure why you would want to put that in a wet clutch?
It is a fact you can put 20/50 Syn oil in the tranny and primary and change out every 8-10 k miles.
I don't.
I put Amsoil severe gear 75/90 SYN in my tranny 2 years ago and it still looks clean today! No junk on the magnet and shifts excellent. Might change it next year - maybe.
Anyone have a car with manual tranny? How often you change the tranny fluid. Once every 5 years - maybe. Why would you need to change it more often in the bike? Because they say so. The dealer only wants to make money on your buying his oil. Or them doing the work.
Motor yes, Syn every 8k. Whatever flavor you like.
Primary yes. Castrol 20/50 dino oil every 8k.
JMO.

 

Please tell me that since the motor has a gear driven oil pump you are not saying gear oil would be better for the motor.

 

You're not referring to me are you? "No engine oil" I meant in the trans, not no engine oil throughout the bike.

 

No, I am only pointing out an obvious flaw in the previously presented argument point that motor oil is not acceptable gear oil in high performance engines...

 

Looks like your Father in law knows how to have a good time. Great pics.

 

You guys don't give up do you, how many pounds of pressure does a TC oil pump put out? How many foot pounds of torque does it take to roll that fat *** hog down the road? Now we are comparing channeling fluid to transferring torque. NEXT.

 

Mark, the most compelling argument might be that virtually all Japanese bikes use engine oil to lube the transmission. I ran a built, nitrous-injected Kawasaki for years, with regular dragstrip use, and never had any transmission problems. A buddy set 3 or 4 Maxton Mile records on various turbocharged Japanese bikes (250 to 350-ish horsepower), and these stock transmissions did fine too. Transmission output shaft torque and rear wheel torque on these would have been way over what just about any Harley can produce.

So what's up with Harley and Baker transmissions needing a special high-pressure lube? Are the tolerances and machining not as precise or something? Material quality or heat-treating not as good? Poorer design?

Edit: One of my friend's records was a 220 mph trap speed (from a standing start) on a 1000 cc licensed and legal street bike.