Compression Release failure

[BroadBand]

Over the weekend, during a 250 mile charity poker run, I had a compression release destroy itself. It's the first real thing that has gone wrong on my Big Dog and it did not leave me stranded. I have 13,500 miles on it when I was putting along at 75mph and heard a loud pop. From that point on, I could hear a new & different sound. Did not really notice a loss of power or anything.

At the next stop, I looked down to see the rear jug CR laying in the hole with the silicone boot kitty wampas. Everything was out of whack big time.

Called my mechanic and he said it would probably not hurt anything to finish the ride and since I was 150 miles from home, that was a relief.

The bike started OK everytime I shut it down. You could definetly hear the "che - che" sound of escaping compression out the small hole in the CR.

Upon tear down, some of the CR was no where to be found. It either melted of broke off between here and there...

It takes a special tool to remove/install the CR's. I replaced both with brand new CR's at a cost of $365 approx. I needed the 2 CR's and 2 gaskets for the rockers. It's now running strong like always.

What follows are pictures of the old parts so you can get an idea of what the CR's look like incase you never have had all the fun this trip turned out to be.

:flag:

 

[TCALZ06]

Nice write up.

Where did you buy the tool to remove them and how much did it cost?

 

[Eric]

mine did the same thing with less than 3K on it.. rear cyl... it was under warrenty though...

 

[BroadBand]

Compression release tool

Nice write up.

Where did you buy the tool to remove them and how much did it cost?

The S&S tool is around $80.00 and is pictured HERE

:flag:

 

[alphadog]

Thanks for the info. Good to know. I would be curious to see how many others fail and at what mileage so we can replace em before they blow.

 

[Big Bruno]

What can I use to loosen a sticky CR? When I start, I have to crack the throttle. Front cylinder.

 

[Eric]

I now have had to replace the frt cyl.to.. about 300 miles after the rear (rear relpaces right before warrenty went out) I bought the S&S comp.release tool & I got 2 comp releases ,replaced the frt & got a spare now.. now that I got 2 bdm with em I figured I had better invest in em & keep @ least 1 on hand.. not a difficult job .. the dam rubber cap is more difficult than the comp release..

 

[Nomad2day]

What can I use to loosen a sticky CR? When I start, I have to crack the throttle. Front cylinder.

You can manually press it down before you start it.
Carbon builds up on them as well and makes them stick as well. Just pull the rubber boot off and use some good penetrating oil on it and press on it until it loosens and springs up on it's own. I use Kroil penetrating oil myself.
Been there and done this already. I also have the S&S tool as well.
Neil

 

[BigDogBro1]

I want to pull the compression release valves out and check for maintenance. Can I use a deep well 12pt socket to remove them?

WHAT SIZE SOCKET?......12point, 1", 3/8" drive or what? 2-3/4" clear deep bore I've read on other another post.

If a deep well socket will work I'll cut a hole in the side of it to allow the CR cable to exit out. Or cut out an extension corner.

Do you need to pull the rocker covers off to get access to the CR for removal?

Thanks

 

[john sachs]

:up:

I want to pull the compression release valves out and check for maintenance. Can I use a deep well 12pt socket to remove them?

WHAT SIZE SOCKET?......12point, 1", 3/8" drive or what? 2-3/4" clear deep bore I've read on other another post.

If a deep well socket will work I'll cut a hole in the side of it to allow the CR cable to exit out. Or cut out an extension corner.

Do you need to pull the rocker covers off to get access to the CR for removal?

Thanks

NO,NO, NO.............
Pull rockerbox top,and sometimes you need to remove the rocker arm saddle.
Use only the S&S tool.The threads are VERY fragile. :bang:
Do the job the right way. :up:
John

 

[billyberoux]

Mine were always failing on my 04 big dog chopper so I pulled them out and plugged them up wth bolts and I've never had a problem starting the bike. The tool costs $60 but most shops will loan it to you so long as you put a deposit down.

 

[BigDogBro1]

I want to pull the compression release valves out and check for maintenance.

WHAT SIZE SOCKET?......12point, 1", 3/8" drive or what? 2-3/4" clear deep bore I've read on other another post.

If a deep well socket will work I'll cut a hole in the side of it to allow the CR cable to exit out. Or cut out an extension corner.


Thanks

.

 

[BroadBand]

.

Hard to argue with that!!

:flag:

 

[uberhawg]

Excellent writeup. S&S doesn't let them show the price online but Retrocycle has that tool for $80.99 if you want one.

 

[Tom Chop]

Thanks To Neil In Tennessee

Nomad2day I appreciate the info on how to clean and lube the compression releases on our beloved "Dogs". I further agree that Krull Oil and lube would be best candidate for breaking down the carbon and lubing the "CR`s". Thank You Nomad2day and all contributers for the great tips. As usual here on the forum you all rock. :flag: :2thumbs: :roll:

Thank You All

Be Kind

Take Care

Tom Chop

 

[TCALZ06]

Looks like I have a rear compression release not working.

Where are you guys buying these at? I see the kits but I only need one.

thanks

 

[HotWheelz]

What about just installing a set of manual Compression releases. My buddy had to install them on his 10.5/1 96 cu Harley.Why do it electronically?

 

[V]

Looks like I have a rear compression release not working.

Where are you guys buying these at? I see the kits but I only need one.

thanks

Just replace my rear one on friday. Got it from Lena At Strokers

 

[V]

What about just installing a set of manual Compression releases. My buddy had to install them on his 10.5/1 96 cu Harley.Why do it electronically?

S&S has a manual set that has a cable that goes to both of them. I don't really like the looks of that set up. There are a couple of others out there wtih the 14mm thread that look like they would fit and you just push down on the top of them. If they would work that would be my choice.
Then theres also having the head machined and thread for the 10mm ones.

Anybody runnin the manual releases?

 

[awg]

Well it seems like a big expense when they fail. What harm to just plug them up and get rid of them?