M8 trans fluid leaking in primary

[Hossamania]

I know it would really frost me if I took a trip on my brand new motorcycle and had to check the tranny every day. It would really ruin the fun.

Think how bad it would be to have to check fluids ever day, adjust and lube chains every morning in the hotel parking lot when you ride on a trip, patch your tubes on the side fo the rode and other regular stuff that no one should ever have to do on a motorcycle.  I sure am glad we never had to do stuff like that.  Checking a fluid every day?  Oh my goodness that would rune a hole trip!

It wouldn't ruin the trip, but I have a 17 year old bike that doesn't give me grief. Having a brand new one that does would be frustrating.
If it was one time thing and I could get it fixed, I could live with that, but knowing it seems to be a design problem and there is no fix, that would frost me.

[1FSTRK]

Over 68000 views and 100 pages of comment on this issue on another forum.
I would love to get to a solution on this.
How is it going Durwood?

The short story is that after 1200 miles and 2 dyno sessions including full tunes and over 60 max power runs my bike transferred 3oz of fluid.

This is much improved from the same transfer amount with less than 500 miles prior to modifying the gasket, so I opened the whole significantly more to see what happens.

I am not convinced as of yet that this phenomenon is exclusive to the Milwaukee Eight, I serviced a 2016 FLTRU equipped with a hydraulic clutch a couple of days ago, the primary fluid level was at the point of running out the service hole in the cover and the transmission fluid level was extremely low on the stick.

It will be a while before I can confirm, but it sure looks suspicious.

Interesting info, if it is a hydralic clutch issue and not a M-8 issue I would look to the pictures in this post
http://www.harleytechtalk.com/htt/index.php?topic=96613.msg1159595#msg1159595

I have never seen or worked on one of these late hydraulic set ups but I can see how the oil would pool in the cavity on the outside of the MS bearing and rise high enough to run down the MS into the primary. I would think a relief in the bottom of the area FSG marked with the red circle would allow fluid to drain rather then accumulate above the shaft level. Making it more of a splash system and less of a bath system. Could be as simple as your trans end cover is sumping.
Hard to tell without having pieces in hand so all just a guess on my part at this point.

[Karl H.]

What FSG said in reply #221 

[PoorUB]

I know it would really frost me if I took a trip on my brand new motorcycle and had to check the tranny every day. It would really ruin the fun.

Think how bad it would be to have to check fluids ever day, adjust and lube chains every morning in the hotel parking lot when you ride on a trip, patch your tubes on the side fo the rode and other regular stuff that no one should ever have to do on a motorcycle.  I sure am glad we never had to do stuff like that.  Checking a fluid every day?  Oh my goodness that would rune a hole trip!

Checking the fluids every day is no big deal, having to refill the tranny every 100 miles and drain the primary would end the trip for me.
It is not 1903 anymore. You do not have to do major maintenance every day to keep a motorcycle running. How would you feel if you bought a new car and had to put a quart of oil in the engine every 100 miles.

If I had just spent close to $30K for a motorcycle and I had to stop every 100 miles, drain the primary and refill the tranny  and the dealer said there was no repair he would get that motorcycle shoved up his backside. If your typical day of riding it to the corner bar and back it is no big deal, but I have been known to do 1,000 mile days. That would be 10 stops to drain and refill, it is not going to happen.

[Rockout Rocker Products]

I am not convinced as of yet that this phenomenon is exclusive to the Milwaukee Eight, I serviced a 2016 FLTRU equipped with a hydraulic clutch a couple of days ago, the primary fluid level was at the point of running out the service hole in the cover and the transmission fluid level was extremely low on the stick.

It will be a while before I can confirm, but it sure looks suspicious.

Hmmm.... all twin cams got the narrow primary in '16. That said, my '15 Limited Low also has the narrow version and has never had a problem.

[Durwood]

Over 68000 views and 100 pages of comment on this issue on another forum.
I would love to get to a solution on this.
How is it going Durwood?

The short story is that after 1200 miles and 2 dyno sessions including full tunes and over 60 max power runs my bike transferred 3oz of fluid.

This is much improved from the same transfer amount with less than 500 miles prior to modifying the gasket, so I opened the whole significantly more to see what happens.

I am not convinced as of yet that this phenomenon is exclusive to the Milwaukee Eight, I serviced a 2016 FLTRU equipped with a hydraulic clutch a couple of days ago, the primary fluid level was at the point of running out the service hole in the cover and the transmission fluid level was extremely low on the stick.

It will be a while before I can confirm, but it sure looks suspicious.

Interesting info, if it is a hydralic clutch issue and not a M-8 issue I would look to the pictures in this post
http://www.harleytechtalk.com/htt/index.php?topic=96613.msg1159595#msg1159595

I have never seen or worked on one of these late hydraulic set ups but I can see how the oil would pool in the cavity on the outside of the MS bearing and rise high enough to run down the MS into the primary. I would think a relief in the bottom of the area FSG marked with the red circle would allow fluid to drain rather then accumulate above the shaft level. Making it more of a splash system and less of a bath system. Could be as simple as your trans end cover is sumping.
Hard to tell without having pieces in hand so all just a guess on my part at this point.

Could very well be Eric, time will tell. I have a derby cover coming to modify with a nipple to use my pressure/vacuum gauge to monitor what's going on while on the dyno.

I am not convinced as of yet that this phenomenon is exclusive to the Milwaukee Eight, I serviced a 2016 FLTRU equipped with a hydraulic clutch a couple of days ago, the primary fluid level was at the point of running out the service hole in the cover and the transmission fluid level was extremely low on the stick.

It will be a while before I can confirm, but it sure looks suspicious.

Hmmm.... all twin cams got the narrow primary in '16. That said, my '15 Limited Low also has the narrow version and has never had a problem.

It could be a coincidence but I have a hard time believing that someone filled that primary all the way to the service hole.

[Durwood]

What FSG said in reply #221 

We've been discussing doing the FSG mod after some further testing.

[bigal51]

I can tell you my experience.  17 Fltru.  Went on 23 day trip to California.  Did over 8ooo miles.  Sometime on the way home I noticed It was getting a little hard to find neutral.  No big deal.  When I got home you guys already started this thread.  I read it and went to check the Tran and sure enough, the level didn't read on the dipstick.  I did another service on it and the primary was 12 oz overfilled.  Tranny was 12oz under filled.  I doubt it hurt anything.  shifts fine and neutral is easy to find.  Will try the fix soon. 

[harleytuner]

I can tell you my experience.  17 Fltru.  Went on 23 day trip to California.  Did over 8ooo miles.  Sometime on the way home I noticed It was getting a little hard to find neutral.  No big deal.  When I got home you guys already started this thread.  I read it and went to check the Tran and sure enough, the level didn't read on the dipstick.  I did another service on it and the primary was 12 oz overfilled.  Tranny was 12oz under filled.  I doubt it hurt anything.  shifts fine and neutral is easy to find.  Will try the fix soon.

You will here the trans gears whine before any damage is done.

[HV]

Now have 2 with transfer to the Primary ..HD Fix......change the Crank seal... 

[1FSTRK]

Now have 2 with transfer to the Primary ..HD Fix......change the Crank seal... 

HV is the crank seal an update version or do they use the same seal as the original production?
Is the M-8 seal a double spring like the Twin cam or a single spring like the Evo?

[HV]

Same as original as far as I can find out...Ill check it out when we get the new seals....

[FSG]

The "half split rule" is the easiest way to trouble shoot a problem. 

It's often a problem applying the rule to motorcycles, but in the case of oil migration trannie to primary it's straight forward IMO.

It's either the primary sucking it across OR the trannie pumping it across.

I'd bang a vent into the primary and then see if the migration continues, if yes then the trannie is pumping it, if no then the primary is sucking it.

NOTE: easy for me to say this as I've no access to an M8, yet

[98fxstc]

The "half split rule" is the easiest way to trouble shoot a problem. 

It's often a problem applying the rule to motorcycles, but in the case of oil migration trannie to primary it's straight forward IMO.

It's either the primary sucking it across OR the trannie pumping it across.

I'd bang a vent into the primary and then see if the migration continues, if yes then the trannie is pumping it, if no then the primary is sucking it.

NOTE: easy for me to say this as I've no access to an M8, yet

I have a derby cover coming to modify with a nipple to use my pressure/vacuum gauge to monitor what's going on while on the dyno.

I know you like your powervision Daren 
but a green TTS would be very useful for this

[1FSTRK]

The "half split rule" is the easiest way to trouble shoot a problem. 

It's often a problem applying the rule to motorcycles, but in the case of oil migration trannie to primary it's straight forward IMO.

It's either the primary sucking it across OR the trannie pumping it across.

I'd bang a vent into the primary and then see if the migration continues, if yes then the trannie is pumping it, if no then the primary is sucking it.

NOTE: easy for me to say this as I've no access to an M8, yet

I have a derby cover coming to modify with a nipple to use my pressure/vacuum gauge to monitor what's going on while on the dyno.

I know you like your powervision Daren 
but a green TTS would be very useful for this

The Dynoware RT has the ability to run those sensors and graph them right on the dyno run. With the old WinPep 7 you could run up to 4 inputs on the graph through the analog box. The TTS green is nice if you have no dyno to use.

[harleytuner]

Same as original as far as I can find out...Ill check it out when we get the new seals....

Are you changing the spacer along with the seal?  I believe there's an updated apart number for the spacer.

[Durwood]

Same as original as far as I can find out...Ill check it out when we get the new seals....

Are you changing the spacer along with the seal?  I believe there's an updated apart number for the spacer.

According to the dealer here, the part number didn't change. That's one reason why I didn't go for that yet.

[98fxstc]

The "half split rule" is the easiest way to trouble shoot a problem. 

It's often a problem applying the rule to motorcycles, but in the case of oil migration trannie to primary it's straight forward IMO.

It's either the primary sucking it across OR the trannie pumping it across.

I'd bang a vent into the primary and then see if the migration continues, if yes then the trannie is pumping it, if no then the primary is sucking it.

NOTE: easy for me to say this as I've no access to an M8, yet

I have a derby cover coming to modify with a nipple to use my pressure/vacuum gauge to monitor what's going on while on the dyno.

I know you like your powervision Daren 
but a green TTS would be very useful for this

The Dynoware RT has the ability to run those sensors and graph them right on the dyno run. With the old WinPep 7 you could run up to 4 inputs on the graph through the analog box. The TTS green is nice if you have no dyno to use.

The green TTS is even better with the dyno
under controlled conditions
the pressure/vacuum gauge readings could be checked against any MAP and RPM values where migration may occur

[harleytuner]

Same as original as far as I can find out...Ill check it out when we get the new seals....

Are you changing the spacer along with the seal?  I believe there's an updated apart number for the spacer.

According to the dealer here, the part number didn't change. That's one reason why I didn't go for that yet.

Not sure when they changed it.  The new HD checklist has replace both the seal and the spacer.  Steve verified this when they did his.  Apparently they are putting more of a bevel on the spacer, theory being that they previous sharp edge was possibly tearing the seal.  At least that's what i've been told.  How long ago did you inquire with the dealer about it?  Steve's was replaced about a week or so ago.

[steve2100]

Mine is migrating trans.fluid also to the primary i had gear oil in the trans.and had to add a few ounces ever so often.My clutch slipped and i drained the primary and it was over full and had the smell of gear oil.

[rbabos]

I really don't know why someone don't vac test the primary on a problem child and once and for all rule out or confirm a seal issue. I don't own one so can't verify it myself. I still suspect possibly two areas. Venting, bearing drain or whatever as well as a source to multiply the oil transfer. The seal still seems to be a suspect area to me.
Ron

[harleytuner]

I really don't know why someone don't vac test the primary on a problem child and once and for all rule out or confirm a seal issue. I don't own one so can't verify it myself. I still suspect possibly two areas. Venting, bearing drain or whatever as well as a source to multiply the oil transfer. The seal still seems to be a suspect area to me.
Ron

I had planned on it but haven't had another one in with the problem.  I posted about venting through the derby cover probably a month ago but it got passed over lol

[rbabos]

I really don't know why someone don't vac test the primary on a problem child and once and for all rule out or confirm a seal issue. I don't own one so can't verify it myself. I still suspect possibly two areas. Venting, bearing drain or whatever as well as a source to multiply the oil transfer. The seal still seems to be a suspect area to me.
Ron

I had planned on it but haven't had another one in with the problem.  I posted about venting through the derby cover probably a month ago but it got passed over lol

I think we were on the same on the venting as a test scenario , then we moved our thinking  into why additional venting was needed in the first place at least I did. Same page again on the gauge testing. I know you will test it when the opportunity presents itself but there are several that can run it through it's paces, gauge installed however. Several sources of feedback is good also.
Ron

[harleytuner]

I really don't know why someone don't vac test the primary on a problem child and once and for all rule out or confirm a seal issue. I don't own one so can't verify it myself. I still suspect possibly two areas. Venting, bearing drain or whatever as well as a source to multiply the oil transfer. The seal still seems to be a suspect area to me.
Ron

I had planned on it but haven't had another one in with the problem.  I posted about venting through the derby cover probably a month ago but it got passed over lol

I think we were on the same on the venting as a test scenario , then we moved our thinking  into why additional venting was needed in the first place at least I did. Same page again on the gauge testing. I know you will test it when the opportunity presents itself but there are several that can run it through it's paces, gauge installed however. Several sources of feedback is good also.
Ron

My line of thought was additional venting is possible due to the smaller primary and transmission cavities.  I personally think the problem lies more in the trans than the primary, but independently venting the primary would quickly rule that whole side out.  MoCo seams to be throwing multiple things at it all at once hoping something sticks.  Problem with that is, if you try 10 different things at once and the problem is solved, which of the 10 things (or combo of) fixed it?  As I said before , i'll test the simple easy things, but it's really the MoCo's problem to solve. I wouldn't pay that kind of money for a new bike to HAVE to work on it.

[1FSTRK]

A simple test on the dyno would be to record the engine pressure, primary pressure. and trans pressure while dyno tuning a bike. At the end you would be able to graph all three with rpm and see when and where the changes occur.

I more and more think this is a fliud trapped problem and not a gas pressure problem. Even with pressure you would need a lot of flow to transfer 22oz of heavey oil in vapor form.