Automatic Compression Release

Jul 30, 2012
125
7
Dandridge, TN
Does anyone know if the 103 CID engine in the Harley Tri -Glide has automatic compression releases? My reason for asking is it is a set-up option that you have to set before using any downloads for the Power Vision system. I know that my 110 had them, but not sure about the 103. Any help would be greatly appreciated, thanks.

Tracy
 
Thanks Everyone, it is so cool to be able to get information when need. I love this web site. My hat is off to all the people involved in building this wonderful home for all of us Trikers, thanks again.
 
If I read this correctly, my 2010 TG has the auto comp release, is this correct? My dealer tried to sell me a set :( I told him it started fine.
 
A compression release (electric or manual) opens a valve when starting the engine they are usually mounted on the cylinder heads.. Helps start the bike easier instead of having all that pressure building up before starting the engine..Helps with other things like draining the battery faster and starter kickback etc..
 
Thanks for the explanation. Kind of makes you wonder why Kimber45's dealer tried to sell him this when it's already on the trike. I realized the TriGlide is "new" but come on, it's been around now for going on five years and they still don't know things like this? Kind of scary for those of us that know next to nothing about engines being sold things that we don't need or already have.
 
Thanks for the explanation. Kind of makes you wonder why Kimber45's dealer tried to sell him this when it's already on the trike. I realized the TriGlide is "new" but come on, it's been around now for going on five years and they still don't know things like this? Kind of scary for those of us that know next to nothing about engines being sold things that we don't need or already have.
Thats is why everyone needs to do there research before heading to any dealer as in some cases they will sell you the kitchen sink if they could..

Reminds me car dealers trying to sell you undercoating and other nick nacks that puts more money in there pockets..
 
OH NO, you mean I didn't need undercoating?!?!?!?!

Seriously, this site provides so much good information on this site that before I do ANYTHING to the trikes engine, exhaust, etc., I'll be checking on here for good, solid information.
 
Thanks for the explanation. Kind of makes you wonder why Kimber45's dealer tried to sell him this when it's already on the trike. I realized the TriGlide is "new" but come on, it's been around now for going on five years and they still don't know things like this? Kind of scary for those of us that know next to nothing about engines being sold things that we don't need or already have.


You would be amazed at the limited knowledge a good many dealers truly poses, they give good dealers a bad name. Harley Davidson started installing automatic compression releases on all Police 103's later in the 07 MY once they found the Motor Officers where having starter kick back on heat soaked startups. The only 103's which don't come with ACR's as standard equipment are dealer built 103's.
 
A compression release (electric or manual) opens a valve when starting the engine they are usually mounted on the cylinder heads.. Helps start the bike easier instead of having all that pressure building up before starting the engine..Helps with other things like draining the battery faster and starter kickback etc..

What trikemutha said is correct but just to clarify, the compression release does not open a intake or exhaust valve but is actually the valve itself , it vents the head to the atmosphere and closes after the engine starts.
The manual release is pushed in by hand on each head , its located near the spark plug, and stays open until cylinder compresion forces it closed. The automatic one, located closer to the middle of the head is opened by an electrical pulse to a coil which is part of the unit itself and closes the same as the manual valve. Both types take a few good pumps of the pistons at speed (idle speed will usually do it but I give it a little rev up)to close so just cranking the motor usually wont close them by itself.
 
You would be amazed at the limited knowledge a good many dealers truly poses, they give good dealers a bad name. Harley Davidson started installing automatic compression releases on all Police 103's later in the 07 MY once they found the Motor Officers where having starter kick back on heat soaked startups. The only 103's which don't come with ACR's as standard equipment are dealer built 103's.

That is again correct Mike. I had them put mech. releases in my 2010 103 build. In fact, it starts better with only the rear cyl. released.

But, don't forget to use them......... so I reset them after shutdown instead of start-up. A little hotter on the finger that way, but it helps my memory.:D
 
That is again correct Mike. I had them put mech. releases in my 2010 103 build. In fact, it starts better with only the rear cyl. released.

But, don't forget to use them......... so I reset them after shutdown instead of start-up. A little hotter on the finger that way, but it helps my memory.:D

My 120 sure won't start without them, and its particular on how long they stay in. When I'm doing a hot start after getting gas I was having to hold the back one in because they were popping off too soon. I ended up having Dan Baisley make me a set of his modified releases. He builds the releases based on the size engine and compression, pricey at $178 for a set but well worth it when you consider I'm still running the original starter which came with my 06. The only thing I've done is install larger battery cables.
 
My 120 sure won't start without them, and its particular on how long they stay in. When I'm doing a hot start after getting gas I was having to hold the back one in because they were popping off too soon. I ended up having Dan Baisley make me a set of his modified releases. He builds the releases based on the size engine and compression, pricey at $178 for a set but well worth it when you consider I'm still running the original starter which came with my 06. The only thing I've done is install larger battery cables.
wow thats cool..you were still able to use the same starter..them 120CU are a hoot to start with out the compression releases..
 
Harley actually did a recall on the 2007 Police 103's to install the ACR's. My trike is built off a 07 Police Road King that I bought new from Harley. It was a factory demo in the northeast and when winter set in they sold it rather then ship it back to York. I am a LEO and was able to purchase it in October of 06. I got the recall in the spring of 07. They have worked flawlessly since installed.
 
My 120 sure won't start without them, and its particular on how long they stay in. When I'm doing a hot start after getting gas I was having to hold the back one in because they were popping off too soon. I ended up having Dan Baisley make me a set of his modified releases. He builds the releases based on the size engine and compression, pricey at $178 for a set but well worth it when you consider I'm still running the original starter which came with my 06. The only thing I've done is install larger battery cables.

Have ya thought about a spark advance/retard left grip ??? (GRIN!:laugh:)
 
Sloufoot, been there done that/ with a kicker to boot. A real beeetch when flooded.
Knee is O)K though.........

eighty80.
 
wow thats cool..you were still able to use the same starter..them 120CU are a hoot to start with out the compression releases..


You might get lucky when its dead cold, once warm its game over and time for some releases. I could have gone with a later intake closing cam which would have lowered the CCP more and let me get away with only using them on heat soak starts. I was looking to keep my bottom end torque coming in soon, I figure 115 ft/lbs at 2,500 rpm is pretty good.
 
Sounds like fun, bet you wished for some electric start about that time.

Yup! Remember a Sportster I had that was a kicker. I was at Geneva on the Lake. Eddies Grill as matter of fact. I rode up there with 4 other guys.

Got ready to leave, everyone is already started except me. Well you guessed it, I flooded it!
They all shut theirs off and stood around watching me kick, and kick, and kick. Then my so called buddy started counting and jabbin me. So I would not stop kickin.
Now a big crowd gathers. About 20 or so riders. I am not about to stop now.
FRinally after about 30 kicks it fires. They all clap, cheer, and high five. The other buds all fire up to leave and I shut down!! Now they shut down again and ask "now what's wrong"?

I was too tired to ride and had to take a break! That's no chit.

I had a 1972 electric start Sporty at one time also back in '72. Got harassed, by some riders, cause it was electric start and the oil tank was in the wrong spot for a true Harley. Go figure.

By the way ACR's on the 120R.
 
In '65 I had a "left twister" on a '53 Indian Chief. Big, & heavy with one big seat for two w/butt rail. 80 inches of pure hell if you didn't know how to start it right !
A number of times I had to remove the plugs & dry out. Someone had put the wrong coils on it. Big difference when ya got good spark ! ha
 
Yup! Remember a Sportster I had that was a kicker. I was at Geneva on the Lake. Eddies Grill as matter of fact. I rode up there with 4 other guys.

Got ready to leave, everyone is already started except me. Well you guessed it, I flooded it!
They all shut theirs off and stood around watching me kick, and kick, and kick. Then my so called buddy started counting and jabbin me. So I would not stop kickin.
Now a big crowd gathers. About 20 or so riders. I am not about to stop now.
FRinally after about 30 kicks it fires. They all clap, cheer, and high five. The other buds all fire up to leave and I shut down!! Now they shut down again and ask "now what's wrong"?

I was too tired to ride and had to take a break! That's no chit.

I had a 1972 electric start Sporty at one time also back in '72. Got harassed, by some riders, cause it was electric start and the oil tank was in the wrong spot for a true Harley. Go figure.

By the way ACR's on the 120R.

Sounds like you have some great friends:laugh:.
 

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