I have a new to me '95 fatboy. The clutch shifts incredibly smooth for a 30 year old bike with 33,000 miles. I would like to refill with the same ftype of luid that comes out. Any way to diagnose what drains out? Smell, thick or thin? Gear oil usually has a unique smell. Trial and error maybe? Thank you all for the help

 

Go with Harley Davidson Formula + It has worked well on all of the 5 Harley's I have owned since 2006

 

I've gone over to Amsoil...they have fluid for both the transmission and the primary...

 

You have to taste it, and compare it to all the lubes available.

Seriously, there is no way to know what is in there.

You don`t need to spend a lot of money for lube for a 5 speed primary drive...

 

I've run type 3 ATF in my primarys for years. never a problem.

 

H-D primary fluid
10W40 dino oil
ATF

They all work. Just make sure you fill it to proper level for your bike. In the real world, 1 Qt works fine.

 

20-50 conventional oil in the motor. Don't use synthetic, since will hear more engine rocker noise since it runs thinner, and if still running oem gaskets, just asking for leaks.
If you can find 20-60 or even straight 50 weight that is not an arm and leg in cost, can run with it instead. Hence the thicker the oil, the quieter the motor will run.

As for oil filters, I use the K&N filters since it has the wrench flat on it and they are chrome, but if you want to keep is cheap, use the walmart super tech ST3614 filters and spray paint it black instead (both made by Champion and are the same filters internally).

10-40w conventional oil in the primary. You can use ATF since it thinner and have less fluid stiction, but will get a little more chain noise from the thinner fluid. Don't use synthetic, since will be too slick for the clutch friction discs, and don't use 20-50 in the primary, since it too thick and causes clutch plate fluid stiction problems when trying to get into neutral.start the motor with the clutch pulled in.
Note, on some of the evos, takes a little over a quart and half to get the level correct. To add, about every 5th primary fluid change (or if I know that I will be pulling the primary cover the next time around as say the 30K marks to change out the spring disc and adjust the primary chain again), will use ATF for that one, since it good getting the last of the dust out of the case that will be left behind that just draining out the standard 10-40 (that it leaves behind).

Trans uses 75-90 gear lube, not motor oil.

On the motor and primary, do fluid changes about every 5K (why your not spending the life savings on expensive fluids since your changing them out before they become dirty in the first place), and learn how to puke the old dirty sump oil out of the filter housing with the motor running, before you put the new filter on.
The filter/assembly filters the oil before its returned to the tank, so with fresh oil back on the motor/tank to the full mark, let motor run for about a min/quart of oil flowing out of the filter assembly until it runs clean, before you shut the motor back down, put the filter on, run the motor for about a min again to fill the filter, then fill the tank up to about the half way mark on the stick.

On the primary, bike needs to be level, and fill the case with fluid to the bottom line of the basket.



On the trans (bike has to be level to check is fluid), about every forth motor/primary oil change. Hence it not so much that the trans fluid gets dirty quickly, it more about checking the oil and the magnetic drain plug to get a feel of if there is a lot of metal in the trans that could be a problem instead. Hence plug may have a few flakes on it, but if you have gobs or big pieces, then you have a gear that is coming apart in the trans instead.

As for brand of fluids, since I am changing them so often on an evo, don't have a problem running the super tech brand to keep the prices down.