On a Harley, does one of the cylinders shut down at idle when the engine overheats?

B

BusterC

New member
I was told this by a friend that said the rear cylinder shuts down on newer models to prevent further overheating and cylinder damage.
 
A

Andy

Member
Yep it's true.On the 09 models it was designed to shut it off at idle if it gets to a certain temp.Twin cams run pretty hot compared to earlier engine designs.
 
C

captainbluey

New member
No, the rear piston assembly in the cylinder is mechanically connected to the crank shaft, as is the front piston. Which means, if one piston is moving, then so is the other one. Your friend is having a lend of you. And it should not be over heating, if it is, then there is something wrong with the motor.
 
B

bob1

Active member
Be careful i hear some one is trying to sell the Brooklyn bridge and he is riding a harley that is over heating.
 
F

Firecrackere

New member
It's part of the temperature management system.
It activates long before "overheat".
There are 3 basic stages.
#1: Reduce idle speed.
#2: Richen the fuel/air mix.
#3: Cut ignition to rear cylinder. (edit: fuel too. Wasn't thinking about having 2 injectors.)

They only do this at idle. At any throttle position above idle, the system reverts to normal operation.
The system has been around since '05, possibly earlier.
It's in my '06 which was built 12/05.

My apologies for possibly not using the correct HD terminology.
I'm working from memory instead of looking it up.
 
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