M8 trans fluid leaking in primary

[rbabos]

FSG's post reply 656 is the most likely fix. Yup. Can't believe how friggin stupid that area is. Slave sealing boot, seriously?
Ron

[Karl H.]

 

[PoorUB]

I agree that the area behind the slave should be opened up. If nothing else a bunch of 1/4" holes drilled across the bottem should do it. I also wonder that if the push rod sticks out as far as it does in this picture,



that placing a hard plastic or a rubber o-ring that fits tight would work as a oil slinger. I would want to use something the would not destroy the tranny if it falls off. But perhaps a small steel washer spot welded on would do it.

[To The Max]

I agree that the area behind the slave should be opened up. If nothing else a bunch of 1/4" holes drilled across the bottem should do it. I also wonder that if the push rod sticks out as far as it does in this picture,



that placing a hard plastic or a rubber o-ring that fits tight would work as a oil slinger. I would want to use something the would not destroy the tranny if it falls off. But perhaps a small steel washer spot welded on would do it.

I was thinking the same thing , but would love to see what would happen if you ran the bike to 3000 rpm with the slave cyl off. Max

[Rockout Rocker Products]

Back when the 17's came out I tried & tried to get the new slave cylinder to try on my '15, I wanted the longer rod travel to help with tranny klank. No one would sell me one... could only be sold/installed by a dealer.

Guess they did me a favor.

[Bigtwin]

-0.5mm in the red zone

[1FSTRK]

Are you saying you removed .5mm and it worked?

[Bigtwin]

It's just my opinion.

oil tranfert : 0.2L / 500km

If HD give me not solution, i try this

[1FSTRK]

.5mm may not be enough on the bottom and that surface is only half the problem. you need to drain the cavity between the slave and the plate also.

[Bigtwin]

maybe - 0.75mm with little holes

Sorry, my English is not very good.

[1FSTRK]

I would not do anything above the center line because it may let more oil in.

[Bigtwin]

so that the oil can flow more easily, it is necessary that the air can return 

we do not know if the oil comes from above or below ?

[1FSTRK]

We know that stock, the oil enters around the hole for the main shaft because that is the only hole.
We don't need more flow, we need drainage. If you create drains in the bottom and leave the
top alone any oil that enters the center hole should flow downward and out the holes.

[Bigtwin]

It may be better indeed :

[Bigtwin]

I do not know if anyone has already done it ?

[1FSTRK]

I do not know if anyone has already done it ?

You may want to read the thread from the page 1
Take a look here.
http://harleytechtalk.com/htt/index.php?topic=96613.msg1192914#msg1192914

[Bigtwin]

I read everything and I did not find the validation of this solution 

[harleytuner]

I do not know if anyone has already done it ?

It has been done with positive results.  The 2 I know of had reduced the transfer probably about 75%.  The next step was to remove a little more material.  I have not heard of the results of the second modification yet.  They are also making some modifications to the mainshaft bearing to test as well.  You are on the right track with want you are suggesting.

[Bigtwin]

In France, my dealer told me right away that it was a known problem but that HD did not really have a solution to offer ......
I do not want to wait for months for a possible solution.
My dealer agrees that I try this solution in the meantime.
Thanks for your help. 

[Bigtwin]

Before drilling holes in this area, I ask myself: what is it for? Protection of the hydraulic menbrane?

[FSG]

Protection against what?

[Bigtwin]

jets of oil under pressure ?

[FSG]

from where? there's none in the trannie.

[Bigtwin]

there must be some pressure in this area for the oil to pass through the pushrod

[FSG]

you say "jets of oil under pressure"

there are none, what we do have in my opinion is the gears on the main and countershafts spinning in toward one another acting as a screw compressor and pushing the oil toward and through the trapdoor bearing on the mainshaft, the slave cylinder is pulsing as a result of feedback from the A&S clutch via the pushrod, it's this pulsing in my opinion that is pushing the oil through to the primary