Most problematic starting/running issues on modern Guzzis over the last ~15 years comes down to two things, battery life and cable cleanliness and connections.
Modern AGMs have fairly short lifespans, especially if not factory prepped. Some last as little as a month or two, down to a few weeks if improperly (rush) prepped. One to two years is an average lifespan on newer small/undersized AGMs. They simply don’t have the energy and AH for modern electronics IMO, despite many who try to debate and declare how great their old AGM battery has been. Yes, many will get longer life from their AGMs, but you'll risk getting stranded when you least expect it. Jump starting motorcycles is risky at best, and much worse if trying to do so on an expired battery; Don't risk the high $ electronics on your bike. Even if you have a basic charger on and it claims charged, and/or your voltmeter or gauge shows 12-13v, it does NOT mean it will start your bike.
We’ve replaced countless expired batteries in my workshop, even on newish bikes, including my well maintained rental fleet. Almost every other bike that arrives to my shop has less than 50% life, even on 1~2 year old bikes. AGM technology arguably has expired, and lithium is a well-proven standard; Our recommended options HERE. Newer bikes are hard on batteries because of “parasitic drain” due the bike’s electronics constantly pulling from the battery even with the key off. Modern plug and forget chargers are very good, if (and only IF) they are designed to do so; Our recommendations HERE. A good battery charger is part of motorcycle ownership. If you have an older one, buy a new one. Make sure your charger is the correct type. Lithium batteries require specialized chargers, don't ignore this. They can balance cells and revive them fully and properly, even when they show no signs of life.
If you have an old charger (of the correct type) and plan on using it, it should be unplugged completely after a 4~8 hr charge weekly in storage. Removing your battery and keeping in a warm place with occasional charging during a (seasonal) storage period will help prolong life as well, especially if below freezing.
Once your battery reaches ~1 year old, best to have it load tested. Charge it fully first, then the old school way is to remove and take it to an Auto Parts Store (which is still an option), however there are cheap and easy modern options available (Amazon links) below. Once checked and charged fully, only then should the charging system voltage be measured at the battery with a voltmeter or device linked below with engine off, then running at idle and 2500 RPM. Voltage ranges should be between 13.6~14.4v max. Higher than a constant ~14.4v can be detrimental to the entire electrical system. Do NOT rely on the dash/gauge readout.
The second consideration for poor starting and error/service messages is terminal cleanliness, bolt AND and cable crimp tightness (we've found many loose or broken), and solid grounding on both ends. Terminal leads corrode in time, often creating a barrier between the terminal and post, so remove both and clean seasonally as a minimum. DeoxIT Shield (or similar product) on the connections is a well-proven solution to help combat this issue. Do NOT use dielectric grease (an insulator). The CARC Guzzis use a fragile/poor M5 stud post spacer, for the starter motor cover, that is nearly always loose and will snap off if you try to tighten it. Best to move the ground strap location to a transmission/gearbox housing bolt. This is usually the culprit for ECU DISCONNECT dashboard errors, or check the ground at the ECU as well. End.
Cheap Batt Tester; a.co/d/0jnmmt9
Install on bike w/phone app; a.co/d/3lDcHl1
Modern AGMs have fairly short lifespans, especially if not factory prepped. Some last as little as a month or two, down to a few weeks if improperly (rush) prepped. One to two years is an average lifespan on newer small/undersized AGMs. They simply don’t have the energy and AH for modern electronics IMO, despite many who try to debate and declare how great their old AGM battery has been. Yes, many will get longer life from their AGMs, but you'll risk getting stranded when you least expect it. Jump starting motorcycles is risky at best, and much worse if trying to do so on an expired battery; Don't risk the high $ electronics on your bike. Even if you have a basic charger on and it claims charged, and/or your voltmeter or gauge shows 12-13v, it does NOT mean it will start your bike.
We’ve replaced countless expired batteries in my workshop, even on newish bikes, including my well maintained rental fleet. Almost every other bike that arrives to my shop has less than 50% life, even on 1~2 year old bikes. AGM technology arguably has expired, and lithium is a well-proven standard; Our recommended options HERE. Newer bikes are hard on batteries because of “parasitic drain” due the bike’s electronics constantly pulling from the battery even with the key off. Modern plug and forget chargers are very good, if (and only IF) they are designed to do so; Our recommendations HERE. A good battery charger is part of motorcycle ownership. If you have an older one, buy a new one. Make sure your charger is the correct type. Lithium batteries require specialized chargers, don't ignore this. They can balance cells and revive them fully and properly, even when they show no signs of life.
If you have an old charger (of the correct type) and plan on using it, it should be unplugged completely after a 4~8 hr charge weekly in storage. Removing your battery and keeping in a warm place with occasional charging during a (seasonal) storage period will help prolong life as well, especially if below freezing.
Once your battery reaches ~1 year old, best to have it load tested. Charge it fully first, then the old school way is to remove and take it to an Auto Parts Store (which is still an option), however there are cheap and easy modern options available (Amazon links) below. Once checked and charged fully, only then should the charging system voltage be measured at the battery with a voltmeter or device linked below with engine off, then running at idle and 2500 RPM. Voltage ranges should be between 13.6~14.4v max. Higher than a constant ~14.4v can be detrimental to the entire electrical system. Do NOT rely on the dash/gauge readout.
The second consideration for poor starting and error/service messages is terminal cleanliness, bolt AND and cable crimp tightness (we've found many loose or broken), and solid grounding on both ends. Terminal leads corrode in time, often creating a barrier between the terminal and post, so remove both and clean seasonally as a minimum. DeoxIT Shield (or similar product) on the connections is a well-proven solution to help combat this issue. Do NOT use dielectric grease (an insulator). The CARC Guzzis use a fragile/poor M5 stud post spacer, for the starter motor cover, that is nearly always loose and will snap off if you try to tighten it. Best to move the ground strap location to a transmission/gearbox housing bolt. This is usually the culprit for ECU DISCONNECT dashboard errors, or check the ground at the ECU as well. End.
Cheap Batt Tester; a.co/d/0jnmmt9
Install on bike w/phone app; a.co/d/3lDcHl1
