Automatic Compression Release (ACRs) Only Work On Second Start Attempt | ACR Problem

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Nov 12, 2020 | 04:59 AM

JimmyAU

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1st Gear

Joined: Aug 2020

Posts: 5

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From: QLD

Automatic Compression Release (ACRs) Only Work On Second Start Attempt | ACR Problem

Background story: I've just completed a new build (pictures attached). Started out with a stock silver '08 FXD Superglide 96ci and ended up with a black 110ci. Photos below for those interested.
Build included:

CVO 110ci jugs and heads (had to bore the cases so the spigot would fit. SE lefty bearings in both cases when reassembled)
Wiseco 10.5:1 high comp forged pistons
Woods TW-777 Cams
S&S Stealth Mini Teardrop Cleaner
Feuling camplate and oil pump
S&S pushrods
TBR Comp-S exhaust
Twin radial Tokico calliper conversion (GSXR) on Low Rider S wheels.
Progressive monotube cartridge kit front, Progressive 490 Sport Shock rear.
Harley combination tacho / digital speedo
Powervision to make it all work. (note - power vision doesn't stay on the bike - might be relevant for later)
Lots of paint.
All work except for the tins was done by myself.
It's a weapon.

Now to the problem. Because the 96ci did no have automatic compression release heads originally, I needed to install the ACR wiring harness from Harley following their instructions and update the Power Vision tune to make them work.

When starting the bike: On first start the ACR does not work. I have tried multiple starting procedures and they don't kick in (e.g. Key OFF, Run switch OFF, Key ON, Run switch ON, Start button | vs. | Key OFF, Run switch ON, Key ON, Start button). The bike will start to turn, pause for a second struggling to overcome compression, then turn over and start. At the moment the starter and battery are able to kick it over but you can tell it takes a lot of effort.

Now this is where it gets interesting, by accident one morning I discovered that if the bike tries to start once and fails, and then tries again the ACR will kick in. I've got this down to - if I turn the bike on (with any run switch / key combination, it doesn't matter) and tap the starter quickly once, just enough for the starter to make a noise, then after that start it normally - the ACRs work correctly. You can hear the bike easily turn over a few times before kicking over.

I'm at a loss as to why this would be the case and am not sure how to approach the problem. Clearly the ACRs do work, but only after the starting circuit has been engaged once before trying to start it. I'm not sure if there is a special start procedure I should be following that I'm unaware of, if it's a tune issue or what. I only use the power vision to tune it, it doesn't stay on the bike so maybe this is related?

Has anyone come across this or have any suggestions to begin diagnostics?

Photos of the build:

Before

After

Nov 12, 2020 | 06:46 AM

todd-67

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Joined: Jun 2009

Posts: 6,899

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From: OH

Following along to see what this ends up being. I did the same thing to my 96" roadking when I took it to a 107". Normally you hear two clicks when the ignition is turned on when they open up. I used the factory upgrade harness and the power vision same as you did. It almost sounds like a pin in the harness isn't making proper contact or in the wrong spot.