[t120rbullet]

It's oil. I don't see why that should hurt the sprag gears. Oil is good for gears and it's not like putting it into a crankcase, be a little thin for that, but the clutch likes it just fine and so does my sprag gears. What have you heard about it t120r?

I guess there is a bearing in there somewhere that is better lubed with a motor oil than ATF. The gears themselves wouldn't care what they got lubed with.
Don't really know as I never had a lectric foot model but I read it here somewhere.

[clamp]

ATF is perfect for needle bearings and sprags. An automatic transmission is where they are.

       Many needle bearings,--- a sprag in the torque convertor and  on some  planetery gears.

    Ever heard of a sprag failure in the torque convertor ,--not much!!

    Symptoms would be on seizure,-- unable to go over 30 MPH

    Locking failure would be,--- no torque and a very high stall test.

[No. 5]

I thought the issue was gravity. A hot bike that sits for several hours or days and all the oil heads south, especially ATF. Did ya ever spill one drop on a hot summer day on the garage floor - a big splash. I thought the Idea with 20w-50 is that more would stick around up top where the sprag is. I'm kickstarting cold anyway.

[Joe28]

Hmmm, oil is always a HOT topic.
I'll toss my quart bottle in the ring.
Here's what I'VE found.
On my '04, the clutches always drag when hot, I replaced the fibers, the steels, the springs, you name it, checked the hub run out, it was a REAL pain!.
I tried Indian motorcycle clutch oil once, (I believe it was 50 wt)?.
This made the clutches slip, same as WAY over filling the case..
I use Motol light gear oil in my off road bikes,UNTIL it gets cold, then ATF. I use ATF in my trials bikes.
Here's what I've learned.
ATF MAY be good for clutch fibers, but take a drop and rub it in my fingers.
Next take a drop of motor oil, rub you fingers.
Now gear oil, same thing.
Feel the "slickness" as you go up in oil weights.
Same in your clutches!
The "heavier" the oil, the more the clutch plates will be lubricated, (slippier).
On my Trials bike, the clutches are-on-off.
I notice my KTM when I switch to ATF in the cold weather, grab more.
That was the quick fix if an off road bike clutches were heading south, dump the gear oil and install ATF. Most times, it'd get you through the moto.
Be careful what oils you put in your clutch case. Some ruin the fibers!
Motor oil is to lubricate an engine, light gear oil, (for 2 stroke engines) are for gears/clutches, ATF is kinda both, but ATF is- hydraulic oil with detergents to keep your tans clean, (if you don't think so, get you hands good and grimy dirty, pour some ATF and rub, your hands will be clean.
So, what I do is.......... When it cold I run ATF, when it's under a load, (my new scoot Will have a side car, so it's a load), ATF to reduce the slipping.
When it's warm I use Motol light gear oil, kinda best of both worlds.
Synthetic ATF is better than Dino oil, it doesn't break down as fast.
An Real old biker tolde me once, " when you start a bike, as it's warming up, work the cluch lever a few times, it gets the plates to "unstick", and gets oil on them". I've had bikes that sit for a while CLUNK when I put it in gear, and my '74 Montesa 175 trials bike will JUMP if I don't work the clutches before I put it in gear.
There, my 2 cents
Joe
So many bikes, so few $$!

[Chasfield]

My 2001 Bullet 500 Deluxe came with ATF in the primary chain case. No problems with slip but the clutch dragged badly when hot (gear change awful). I changed it for cheap 15/40 engine oil. Still no problems with slipping, and dragging has been substantially reduced. The gear change has improved.

The old ATF was full of particles, some metallic. I pulled out the clutch plates and cleaned them with kerosene before putting in the fresh 15/40 oil. I also primed the clutch sprocket/center bearing with oil and noticed immediately how much more smoothly the center assy. turned when spun by hand.

I think also that my primary drive now runs a bit quieter.

My conclusion is that ATF is good where you want friction but may not be adequate as a metal-on-metal lubricant in this application.

[PhilJ]

If your clutch was dragging, it was misadjusted. Since these bikes are not all the same,due to manufacturing methods, the adjusting of the clutch is by feel not by measurement at the lever.
When the bike is warm adjust for no drag setting at a stop with bike in gear, and some play at the lever.

I've been doing my bikes like that for many years, never have I lost a clutch. And I use ATF. The ticker on the RE is now at 4600 miles. The first primary fluid change had some particles expected. The other has not had even close the first. You should always expect some in a clutch, it's the nature of clutches.

[Chasfield]

I tried plenty of adjustment schemes, including minimal slack in the cable and no discernible push-rod clearance. I concluded that the intrinsic clutch drag at full pressure plate lift was greater with ATF in the primary case than when using 15/40 engine oil. I fancied that I could actually feel the difference when operating the kick start with the clutch pulled in - less torque required to make the unloaded plates slip over each other.

Of course, if light-weight engine oil produces clutch slip then it is no use at all. However, so far it it seems to be the best option for me.

[PhilJ]

Well I certainly understand that. It does make me wonder though as to what could be that much different from your experience and mine. Mine felt more free, easier, all the things you described once I switched at the first oil change. The mysteries of the world may never be known.
Oh, it was my understanding that the clutch rod should be backed out 1/8 turn after making contact in the adjustment.

[Chasfield]

Perhaps the improved performance I experienced may have been more to do with the new primary lube being clean rather than it being ATF or engine oil.

Incompressible bits of stuff trapped between the friction linings would dig in and use up precious clutch lift.