Bonneville America Forums Forums Technical Forums General Tech oil bags

i think i know why but help? our bikes are wet clutches, with the oil for the engine and trans all together, on the older bikes the trans and motor oil are seperate is this be cause of temp or cleaner oil for the clutches?

good point, i know the old bike have a oil tank under the seat, i am guessing this is for the trans. oil? our bikes have the trans. and motor using the same oil? hope this is better i am kinded a retared!!!!!!!!!!

The new bikes are unit construction(one piece). The older bikes You are referring to are pre-unit models. It was easier back then to build the motor and transmission seperate. Also if you wanted to make changes to one you did not have to modify the other and it was easier to position the tranny to the rear wheel if needed. I like seperate units because you can run engine oil in the engine and a heavy gear oil in the tranny.(synthetic for both). That's what I did for my old Harley. Also it is easier to make tranny gear changes (different ratios) with a seperated unit......Angelis

No Angelis, unit construction also had 3 seperate oils. The oil bag was engine oil, trans oil went right in the trans and the primary had it's own oil too. They didn't have much filtration on the old bikes and also used dino oil. Dino oil will shear so you don't want engine oil and trans oil together. You don't want Primary oil in either place due to clutch dirt and the lack of good filtration. They also took 3 different viscostiy oils. Depends what year you had as to what they recomended. 20-50 engine oil I run straight 50 straight 50 trans I run 90 and 10-30 primary I run 10-30.

Dog33 you are right.....dog I'm sorry for the misinformation..... It's been a long time since I worked on any of the older bikes. Now I'm starting to feel my age.....Angelis

Hey when you don't play with something in awhile you tend to forget. I still work on those bikes for people and as you know have a couple myself.

You are absolutely right about gearing. On the pre-unit bikes an old trick was to put a final drive tranny sprocket (tranny to rear wheel) on the crank shaft with no shock absorber. In those days the primary and final drive used the same size chain. It gave you many more options as far as gearing without having to crack the trans. They also had what was called a slick shift. When you pushed the gear shift it also disengaged the clutch eliminating the need to use the clutch lever while shifting. Only time you needed the clutch lever was to stop. It didn't really work as well in practice as in theory kinda like the sprung hub.

you guy know your stuff thanks for the info. i hope to find and old triumph and make an old bobber.

Hey dog, don't forget the old, old triumphs (pre 75?) had shifters and brakes on the opposite side of what we have today. I kinda wrestle with that a lot because I have an 02 and an old trumpet and it plays with my brain a little.(granted, it's a very small playing field)

Once you do it for awhile it becomes 2nd nature. I have been jumping back and forth between my old Triumphs (18 and all R shift) and my 64 BMW (L shift) Used to mess me up at first but after years of doing it I don't even think about it anymore. Not that I ride the BMW much anymore and the SM it L shift like the BMW so now most of my time is spent on the SM.

There are a number of reasons that they are different today.

1. New clutch materials don't flood the oil with muck like the old ones.

2. The new gearboxes hold up better and don't fill the oil with huge amounts of shredded metal.

3. The oil system is better filtered now.

4. Considering all the above, the cost of separate oil systems wasn't justified.

When there were 3 separate oil systems, the bikes were anly guaranteed for 90 days, a few for 6 months. And there was also a mile limit. Now Triumph covers the bikes for 2 years with any mileage, and the could only do that if they held up better, so the new oil system must work.

HD jumped the gun on that one or maybe just designed it poorly. They had the primary oil and engine oil together in some of the shovels. I can remember my friends shovel filling up the primary until it came out the top. Also caused shorter engine life.

I agree this is not the case with our bikes. Just look at the mileage some guys have gotten out of them with no signs of needing anything any time soon.

They didn't really combine the primary and engine oil. There was an adjustable feed that added a little oil into the crankcase vent which then blew the oil out onto the primary chain. There was a second feed valve that dribbled oil onto the drive chain. Of course, people being people, these were either adjusted to drop too much oil or were shut off so hard that they leaked. It worked pretty well on some bikes when it was left alone. Where the primary oiler consistently went bad was when the check valve between the oil pump and the tank started to leak. When that happened, oil leaked into the crankcase until it filled to the vent, then it started pouring into the primary cover.

Got ya. As I have said in the past I am no HD mechanic. I thought it was common oil I stand corrected and will take your word for it. What you say makes sense and could easily have been the problem. Must have then starved the engine for oil or something.