Hot start kickback stumper
Road Warrior
Joined: Jul 2009
Posts: 1,745
Likes: 1
From: A house.
I believe you when you say the battery tested good. The dealer would have jumped on a battery sale if it was below spec. A load test is held to simulate start up cranking. That's why a load test is done instead of just putting a voltmeter to the battery.
Do a starter amp draw test. If it's drawing excessive amperage, it may be the culprit. You can rebuild your starter pretty cheap.
Compression releases will solve the problem. You only need to use them in situations where the engine has not had time to sufficiently cool. If, as mentioned earlier, the engine comes to rest at the beginning of a compression stroke and is hot - it's more likely to experience that "kick back." Install Automatic Compression Releases and you won't even have to think about them.
Do a starter amp draw test. If it's drawing excessive amperage, it may be the culprit. You can rebuild your starter pretty cheap.
Compression releases will solve the problem. You only need to use them in situations where the engine has not had time to sufficiently cool. If, as mentioned earlier, the engine comes to rest at the beginning of a compression stroke and is hot - it's more likely to experience that "kick back." Install Automatic Compression Releases and you won't even have to think about them.
Last edited by clicker01; Aug 22, 2012 at 01:45 AM.
Club Member
Joined: Feb 2007
Posts: 16,320
Likes: 306
From: Boynton Beach, FloriDuh
Not uncommon in hotter climates during the hot summer months.
When you shut down the motor, one cylinder virtually always comes to a stop on a compression stroke leaving that cylinder under pressure. When the bike sits for a (longer) period of time, that pressure bleeds off past the rings, valves, etc. When you just shut down for a quick fuel stop, that pressure is still there when you try to restart and the starter doesn't have the torque to build momentum and "push" through the stroke and the motor will tend to kick-back against the starter clutch gear.
What eventually happens, is that the kick-back against the starter clutch gear strips the teeth off of the clutch gear and you'll wind up needing to replace the starter clutch.
Compression releases, good battery or a stronger starter like an All *****, should take care of it.
Also, before you start the hot bike, you can also try putting the bike in 3rd or 4th gear, clutch in, and pop the clutch as you push the bike backwards. That will usually back the piston up enough that the starter won't have a problem.
When you shut down the motor, one cylinder virtually always comes to a stop on a compression stroke leaving that cylinder under pressure. When the bike sits for a (longer) period of time, that pressure bleeds off past the rings, valves, etc. When you just shut down for a quick fuel stop, that pressure is still there when you try to restart and the starter doesn't have the torque to build momentum and "push" through the stroke and the motor will tend to kick-back against the starter clutch gear.
What eventually happens, is that the kick-back against the starter clutch gear strips the teeth off of the clutch gear and you'll wind up needing to replace the starter clutch.
Compression releases, good battery or a stronger starter like an All *****, should take care of it.
Also, before you start the hot bike, you can also try putting the bike in 3rd or 4th gear, clutch in, and pop the clutch as you push the bike backwards. That will usually back the piston up enough that the starter won't have a problem.
Road Warrior
Joined: Jul 2009
Posts: 1,745
Likes: 1
From: A house.
That's an excellent explanation!
Cruiser
Joined: Sep 2010
Posts: 224
Likes: 0
From: 3rd Rock
Hold the start button a little longer when the bike is still warm, if you release the starter button while there is still compression on one of the cylinders too early or before it starts it will kick back on the starter.
Stage II
Joined: Apr 2010
Posts: 2
Likes: 0
From: Summerville, SC
Had the same problem with my 2010 FLHTCU. Noticed the battery voltage would drop below 10vdc every time it happened. Replaced the battery and problem solved. If you're not obsessed about Harley logos, you can get a good battery for about $100 from http://www.batterymart.com/.
Road Master
Joined: Apr 2011
Posts: 1,077
Likes: 2
From: Orlando
Just tap the start button to push it past the compression stroke then push the start as usual. Mine does this if I advance the timing too far
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Outstanding HDF Member
Joined: Jul 2011
Posts: 2,052
Likes: 6
From: North London, UK
Not uncommon in hotter climates during the hot summer months.
When you shut down the motor, one cylinder virtually always comes to a stop on a compression stroke leaving that cylinder under pressure. When the bike sits for a (longer) period of time, that pressure bleeds off past the rings, valves, etc. When you just shut down for a quick fuel stop, that pressure is still there when you try to restart and the starter doesn't have the torque to build momentum and "push" through the stroke and the motor will tend to kick-back against the starter clutch gear.
What eventually happens, is that the kick-back against the starter clutch gear strips the teeth off of the clutch gear and you'll wind up needing to replace the starter clutch.
Compression releases, good battery or a stronger starter like an All *****, should take care of it.
Also, before you start the hot bike, you can also try putting the bike in 3rd or 4th gear, clutch in, and pop the clutch as you push the bike backwards. That will usually back the piston up enough that the starter won't have a problem.
When you shut down the motor, one cylinder virtually always comes to a stop on a compression stroke leaving that cylinder under pressure. When the bike sits for a (longer) period of time, that pressure bleeds off past the rings, valves, etc. When you just shut down for a quick fuel stop, that pressure is still there when you try to restart and the starter doesn't have the torque to build momentum and "push" through the stroke and the motor will tend to kick-back against the starter clutch gear.
What eventually happens, is that the kick-back against the starter clutch gear strips the teeth off of the clutch gear and you'll wind up needing to replace the starter clutch.
Compression releases, good battery or a stronger starter like an All *****, should take care of it.
Also, before you start the hot bike, you can also try putting the bike in 3rd or 4th gear, clutch in, and pop the clutch as you push the bike backwards. That will usually back the piston up enough that the starter won't have a problem.
I have been having this same problem on my 07 Heritage for the last couple of months. Starts great first thing in the morning, but the rest of the day, it kicks back. I have added an octane booster and this has helped, I thought that maybe I was getting pre-ignition of the compression stroke, and boosting the octane has helped a lot, but not eliminated it.
I went to my indy on Tuesday to show him what it is doing, and he asked me to start the bike so he could hear it. I did start the bike while it was leaning on the jiffy stand, and lo and behold no kickback. Wierd, because it does it every time its hot. I turned it off and started it 6 more times on the juffy stand and NO KICKBACK! Now maybe the Heritage was scared of my indy and didn't want to act up, but I tried it again at my local Fred's store after leaving the Indy and still when starting on the juffy stand, no kickback,? Wierd!
Not sure if there is any logical explanation of why it wouldn't kick back on the stand when it does it every time if I am sitting straight up on the bike? Any ideas, or is this coincidence? 7 Starts with no kick back on the jiffy stand when it does it every hot start when sitting straight up seems like an indication of some kind of change, but I don't know the internals of the starter, so..... Any ideas anyone?
I went to my indy on Tuesday to show him what it is doing, and he asked me to start the bike so he could hear it. I did start the bike while it was leaning on the jiffy stand, and lo and behold no kickback. Wierd, because it does it every time its hot. I turned it off and started it 6 more times on the juffy stand and NO KICKBACK! Now maybe the Heritage was scared of my indy and didn't want to act up, but I tried it again at my local Fred's store after leaving the Indy and still when starting on the juffy stand, no kickback,? Wierd!
Not sure if there is any logical explanation of why it wouldn't kick back on the stand when it does it every time if I am sitting straight up on the bike? Any ideas, or is this coincidence? 7 Starts with no kick back on the jiffy stand when it does it every hot start when sitting straight up seems like an indication of some kind of change, but I don't know the internals of the starter, so..... Any ideas anyone?