Harley M8 compression release failure.

[TXChop]

Has anyone seen or heard of a Auto compression release (ACR)failure where the center valve drops out?
I have stock bike in the shop. Sounded like an exhaust leak. Turns out the comp release was burned up and missing the piece that seals the combustion chamber. Exhaust was leaking through the plastic to atmosphere.

Best part is, pulled the cyl head and its perfect inside, no signs of anything bouncing around at all.

[TXChop]

Well at least harley updated the design

[wfolarry]

They probably seen the same thing you did. 

[No Cents]

  makes you wonder where the guts of that release went...if the guts were even in there from the beginning.      I would bet it didn't get hot enough to melt the missing metal piece. Maybe it finally got hot enough over time to finally melt the thru the plastic housing and then the leak was heard. That's a big chunk of metal to just disappear. Definitely a strange one you got there Dan.

[Durwood]

Had one on a Twin Cam do that. The guy wasn't as lucky as yours was.

[goblue90]

Has anyone had any luck getting their hands on a set of these?  They're on back order from HD.  I placed an order at Surdyke at the end of August and the release date has been pushed back a few times already... currently scheduled to ship on 9/22.  I'll believe it when I see it.

[Gliding Joe]

I see where HD has had two updates to these since introduction on the M8 in '17, now on release "B"...... Hmmmmmmm

[TXChop]

Has anyone had any luck getting their hands on a set of these?  They're on back order from HD.  I placed an order at Surdyke at the end of August and the release date has been pushed back a few times already... currently scheduled to ship on 9/22.  I'll believe it when I see it.

I had to drive about 110miles to get this one. No one local had it.

[goblue90]

Just got an email from Surdyke that these are available from HD now, so my backordered ACRs will be shipped to me once they get 'em.  I just reinstalled my upper rocker box covers and oil lines.  Should I take everything back off and replace my old ACRs with the new ones?  Ugh.

[Jmd897]

Backordered to 10/9 with New Castle.

[CarlosGGodfrog]

Are auto and manual compression releases mechanically interchangeable ?

[rigidthumper]

No.   Different operating style, different size. 

[Hossamania]

And different location.

[CarlosGGodfrog]

I get the electrical vs mechanical differences, but how different are the sizes, and as long as they vent the chamber, so what ?

[rigidthumper]

ACRs vent the pressure into the exhaust port, via complex holes/passageways machined into the top of the heads & exhaust ports, via an electronic valve operated by the ECM.
MCRs vent the pressure into the atmosphere via a small ( 3/32") drilled passageway to a 10mm x 1 threaded hole, 5/8" deep, next to the spark plug, using a manual (thumb operated) valve.

[Hossamania]

If you put manual releases into the electric release position, you would not be able to push the button on the manual release.

[Ohio HD]

You can't put a manual release where an auto release is, the threaded holes are different sizes. 

[D-1]

Got one from a 2020 FXLRS has done the same thing. No damage in combustion chamber. No complaint from customer, just pulled it down for big bore kit.