What is "piston slap", and what can silence it?
Road Captain
Joined: Nov 2007
Posts: 697
Likes: 1
From: Just west of Tahoe
Piston slap is the piston skirt contacting the cylinder walls. This normally only happens on start-up and when the engine is cold.
Has nothing to do with the rings.
Over time, it will damage the cylinders in the areas of contact.
That said, I would be more inclined to suspect a bad lifter.
Has nothing to do with the rings.
Over time, it will damage the cylinders in the areas of contact.
That said, I would be more inclined to suspect a bad lifter.
Last edited by scootertramp; Oct 15, 2009 at 03:24 PM.
Advanced
Joined: May 2007
Posts: 59
Likes: 6
From:
For what is worth, I have an 09 flhx that my wife and I travel about 300 to 500 miles on every weekend. I also have brought the bike in for what sounds like piston slap that went away after 5 minutes. It wasnt piston slap, its lifter noise. Until the lifter pumps back up, it makes some noise then goes away. I opted not to have the dealer try to replace anything, my choice. When it wears out I will replace the cam set, maybe add the gear drive, a SE backing plate, high flow pump, cooler, SE lifter and adj rods. All in the interest of making it run more efficient. Good luck with your engine too!
Novice
Joined: May 2015
Posts: 22
Likes: 0
From: waterford mi
what is piston slap
piston slap can only be caused by excessive clearance between the piston and cylinder it happens at the point that the piston changes direction on the compression stroke.what is making the noise is the piston skirt slapping against the cylinder wall as the piston rocks do too the excessive clearance and if not dealt with can cause the skirt too break off causing major damage. the first thing too do is too quite the exhaust as much as you can use a listening device and take the time to locate the exact spot that the noise is coming from otherwise you are guessing and we all know how well that works.If you find that is what it seems too be disassemble the motor and have the clearences checked with the proper equiptment a hole guage micromiter and a dial bore indicater used by a qualified machinist good luck
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