M8 Road glide. Checked the gearbox oil today, on the side stand, and the reading was just on the tip of the dip stick. Bike has been sitting for several days. Another popular Tech Forum has technicians and enthusiasts alike, very concerned about the gearbox oil emptying into the Primary, thus, overfilling the primary.
My bike appears to be doing it at 5000km as does a mates new roadglide at 3500km.
Check your oils and report back please!

 

Just did my 1000 miles service. Mine was fine before and after. Remember when checking trans lube, put the stick in and tighten it ONLY TILL the o ring contacts the case! That description comes from the shop manual. Unlike the twinkies, you must insert it or tighten it into the threads, not just sitting on them. That little bit can give you a false reading.

Good Luck

Eagle Out

 

I believe you are overthinking this a bit. It is highly unlikely that the design engineers would purposely have the gearbox empty into the primary if there were any ill effects. The whole idea of engineering is to make things work better, not to create problems. Check your procedure and make sure you are checking the fluid level correctly and if the bike is low on fluid, add some. Ride more...worry less. If it were a major problem the highways would be littered with the dead carcasses of M8's.

 

It's been discussed here to... While they seem to thing that it's the slave cylinder, I'd say it's the clutch coupled with a smaller tranny vent, looser fit on the pushrod and no oil flinger.. Each time you roll the throttle on and off the clutch pressure plate moves a small amount based on the "slip/assist design" That with possible less venting to the tranny (hose / vent is different from TCs) is slowly pumping oil from the tranny to the primary.

 

I checked mine at 6200 miles. Trans fluid is getting into my primary. I pulled the derby cover and the primary was overfull and leaked out. I know it was trans fluid because the trans was low a while back and I added. No mistaking the smell of severe gear trans oil in my primary. I was surprised it was overfull and did'nt get an exact amount that came out of the primary. Guessing ~4oz. Anyhow I drained and refilled trans and primary.

Visited the dealer at was going on. 1st they heard of it. They asked to schedule the bike for an inspection. Right now I'm monitoring very closely on trans level.
Couple things I want to monitor, then I'll schedule.

 

This issue is know by many. We've spent plenty of time with it and it does occur. The cause is due to higher RPM operation and has been proven time and time again. Each and every M8 will do it if operated in the proper conditions. We have our theory as to why but that really doesn't matter much. All I can tell you is that those of you that ride at higher RPM's more often will see this happening more and those of you that keep RPM below 3500 most of the time will not. Fluid will move from the transmission to the primary and all you can do is keep an eye on the transmission level to not allow it to get too low.

 

Now Steve. under 3500 rpm? What fun is that?

I checked tranny oil in my M8 RK and it has 2K since the last fluids change. Oil is barely touching the end of the tranny dipstick and drained bout 6 oz from the primary.

 

You must be getting old, your younger riding style would have had much more in the primary and less in the transmission

 

well the good news is you never have to change your trans fluid again. just keep topping it off and change the Primary 5 times sooner than recommended! just came back from a 1500 mile group road trip and spent most of the time from 2500 - mostly under 4K rpms, trans was Full, and since I have peak torque of 106 at 3000 rpms I never lacked any get up and go punch and cruising was perfect... when I posted about a month ago that my trans fluid was low and Primary over filled I had been riding 'normal' for me..like I stole it, so Steve and Max are on to something here..glad I've stuck with Formula +, at least not mixing fluids..but once I get out on rides where I'm hammering it I know I need to keep a close eye on levels

 

Are all of the M8 motors affected by this? Is there a fix?