Oil from trans to primary......

[Mykneesbehurtin]

Just some food for thought,when i took my bike to the dealer for brake and trans oil issue the tech said it is his opinion that the m8 is making to much crankcase pressure one reason some of the m8 blow oil out of the air cleaner.So im thinking,how would this make trans oil migrate to the primary.Since the pan holds both the oil and the trans fluid is it possible that the excess pressure is pushing past the gasket on the pan and pressurizing the trans.Just a thought.He told me that he is hearing rumors that HD is working on new engine cases for the M8,so maybe there is something to this.

[MDO]

Just some food for thought,when i took my bike to the dealer for brake and trans oil issue the tech said it is his opinion that the m8 is making to much crankcase pressure one reason some of the m8 blow oil out of the air cleaner.So im thinking,how would this make trans oil migrate to the primary.Since the pan holds both the oil and the trans fluid is it possible that the excess pressure is pushing past the gasket on the pan and pressurizing the trans.Just a thought.He told me that he is hearing rumors that HD is working on new engine cases for the M8,so maybe there is something to this.

I don't believe this to be a correct statement. There's 3 drain plugs.

I heard the same about the cases, but haven't been able to confirm it.

[Mykneesbehurtin]

You are correct there are 3 drain plugs but i think the oil pan holds both the engine oil and trans oil.Maybe some one could find a drawing of one.

[Mykneesbehurtin]

I tried downloading a breakdown of the M8 and it wouldn't let me,but the oil is above the trans fluid in the same pan.And they talk about a new gasket between the engine and the transmission/oil pan because the engine now breaths into that area.

[Jack Klarich]

Here is the break down of the oil pan

# 15 is the oil pan, the baffle on top of the pan is supposed to break up air bubbles to help speed up cooling

[MDO]

You are correct there are 3 drain plugs but i think the oil pan holds both the engine oil and trans oil.Maybe some one could find a drawing of one.

When you pull the transmission drain plug, a quart of the fluid you are using comes out.

Some are using Redline 80-90 weight that look like Pepto-Bismol. Many are using something other than their chosen motor oil.

[Jack Klarich]

I dunno about new cases

Would that mean HD will retro fit all the M8s out there?

I read somewhere HD was making a new improved baffle for the oil pan

[Old Road Dog]

the tech said it is his opinion that the "m8 is making to much crankcase pressure one reason some of the m8 blow oil out of the air cleaner." Oh fer crying out loud.The M8 is now an air compressor that stores compressed gas?Next time you see that stupid kid releive the pressure in his head with a ballpien hammer.

[Jack Klarich]

the tech said it is his opinion that the "m8 is making to much crankcase pressure one reason some of the m8 blow oil out of the air cleaner." Oh fer crying out loud.The M8 is now an air compressor that stores compressed gas?Next time you see that stupid kid releive the pressure in his head with a ballpien hammer.

With a new and bigger crank case and the oil volume of the pan ( oil is up 1 qt over twin cams) expect the internal pressure from the down stroke of the pistons to be higher.

That pressure along with oil and water vapors has to go some where, guess where?

Bigger displacement engines have Always faced this problem

Drag racers knew this years ago and came up with external venting much the same as we now do to our engines

IMO running the head vents up may not prove to do as well as thought, The oily mess has to over come gravity

The breathers in the heads expel the oily mist out but IMO will NOT suck the mess back in, I would opt for gravity to work, run your vent line down



This is JMO from looking at and experimenting with a lot of routes for the breathers

[Capt.Bob]

I have been closely following this thread and checking the transmission fluid on my 2017 M8 Tri Glide with regularity and have not found ANY change in the trans fluid at the 7200 mile mark. Granted, I changed all three holes at 5k miles and put Formula + in both the transmission and primary oil compartments. I used Syn 3 for the engine at the 5k service that I performed myself. At the current time, there is no indication of any migration of fluids. I try and keep the engine oil level 1/2 way up the dipstick add line to reduce the possibility of blow by into my air cleaner. Thus far, no significant oil has been deposited into the air cleaner when checked and there has been no need to clean the air filter which as most know is washable. I am wondering if high RPM operation is sometimes the culprit of these reported problems? My trike generally does not get operated much over the 4k RPM range and when cruising, I don't think I ride anywhere near that RPM on the open road.

[rhino 2]

I have been closely following this thread and checking the transmission fluid on my 2017 M8 Tri Glide with regularity and have not found ANY change in the trans fluid at the 7200 mile mark. Granted, I changed all three holes at 5k miles and put Formula + in both the transmission and primary oil compartments. I used Syn 3 for the engine at the 5k service that I performed myself. At the current time, there is no indication of any migration of fluids. I try and keep the engine oil level 1/2 way up the dipstick add line to reduce the possibility of blow by into my air cleaner. Thus far, no significant oil has been deposited into the air cleaner when checked and there has been no need to clean the air filter which as most know is washable. I am wondering if high RPM operation is sometimes the culprit of these reported problems? My trike generally does not get operated much over the 4k RPM range and when cruising, I don't think I ride anywhere near that RPM on the open road.

Bob.......And herein lie's the rub, They all don't do it...[Trans oil transfer to Primary] It would be better if they all did ' For everyone that's having the problem that is, Then it would addressed,

Without any stone walling from the company..... And no i don't ride over the 4k RPM's...

With my Ex Tri-Glide 103 that i did, Sometimes to 6k RPM's...And never needed to add oil to the tranny or have the primary over flow...

The 103 needed high RPM'S...The M8.....No....

[Jack Klarich]

My Freewheeler was rung out on a dyno with 6K miles, to date with over 17k miles NO transfer Some do it and others do not but IMO given the number that do HD should have some idea why

[Mykneesbehurtin]

I am getting conflicting reports unfortunately only one from a true HD tech,one said it's from suction created in the primary(having a hard time buying this one) had a tech say the m8 creates to much crank case pressure( so why dont all M8s do it),so i am going to find an old derby cover that will fit my M8 and weld a bung on it and insert a vacum boost gauge to see if it has any vacum or any pressure.Just kinda curious.On the HD forum one tech drilled a hole in the upper portion of the inner primary,just top left of the clutch basket and installed an elbow with a hose running back and over the primary to vent the primary,this one is claiming suction in the primary.Waiting on parts for M8 to come in( sticking front left brake caliper) then maybe the shop can give me a answer on my oil migration

[Jack Klarich]

I am getting conflicting reports unfortunately only one from a true HD tech,one said it's from suction created in the primary(having a hard time buying this one) had a tech say the m8 creates to much crank case pressure( so why dont all M8s do it),so i am going to find an old derby cover that will fit my M8 and weld a bung on it and insert a vacum boost gauge to see if it has any vacum or any pressure.Just kinda curious.On the HD forum one tech drilled a hole in the upper portion of the inner primary,just top left of the clutch basket and installed an elbow with a hose running back and over the primary to vent the primary,this one is claiming suction in the primary.Waiting on parts for M8 to come in( sticking front left brake caliper) then maybe the shop can give me a answer on my oil migration

I dunno, what I do know is this problem revolves around the hydraulic clutch models going back to 2014, ya got to ask yourself What did HD do so darn different on these models JMO

[Luvtofish]

Just read a post on another forum about a guy that emphatically believes the issue is caused by the small diameter clutch push rod they put in the M8. He designed a larger diameter one piece push rod that he claims solved the oil transfer issue.

[Casper]

Just read a post on another forum about a guy that emphatically believes the issue is caused by the small diameter clutch push rod they put in the M8. He designed a larger diameter one piece push rod that he claims solved the oil transfer issue.

Read the same posting...buy why doesn’t all of them do it? They all have the same parts.

[Jack Klarich]

Read the same posting...buy why doesn’t all of them do it? They all have the same parts.

Very good question

You would think something this easy would have been stumbled onto by The MOCO

[Luvtofish]

Good question. He makes a good argument around the fact that the primary vents air along the clutch push rod and in to the trans cavity which in turn has an atmospheric vent. The problem bikes are specific to 14 and later with the new smaller diameter hydraulic clutch push rods. Only bikes with this combination are among the group with the potential for developing the oil transfer issue.

I don’t believe the MOCO is coming clean with everything they know. So far everything I’ve seen from them is nothing more than a cheap bandaid.

[rhino 2]

Good question. He makes a good argument around the fact that the primary vents air along the clutch push rod and in to the trans cavity which in turn has an atmospheric vent. The problem bikes are specific to 14 and later with the new smaller diameter hydraulic clutch push rods. Only bikes with this combination are among the group with the potential for developing the oil transfer issue.

I don’t believe the MOCO is coming clean with everything they know. So far everything I’ve seen from them is nothing more than a cheap bandaid.

I'm bringing my 17 in Saturday for the fourth time to have the primary, lowered and the trans filled....And we'll see what story Harley Tech Services comes up with this time..

This time the trans oil is totally off the dip stick in 8 hundred miles since it was filled in the middle of June.. [27 days].....

[Jack Klarich]

I'm bringing my 17 in Saturday for the fourth time to have the primary, lowered and the trans filled....And we'll see what story Harley Tech Services comes up with this time..

This time the trans oil is totally off the dip stick in 8 hundred miles since it was filled in the middle of June.. [27 days].....

Good Luck Bob