Pinging or Knocking After Warm Up

[khutchinson]

Everything was running fine until today on the way home from work. When cold the bike sounds fine but once it warms up there is a higher pitched pinging or knocking sound coming from the rear cylinder. I would think a bad rod bearing would make a noise up top all the time weather it was cold or not so I'm thinking possibly a push rod out of adjustment or a lifter not pumping up completely but still I am confused as to why heat would have anything to do with it.

Details:

80" EVO
Full top end rebuilt a couple months ago
Andrews EV27 Cam
K&N Cone Intake
Short Shot Exhaust

[Thermodyne]

All the time, under load, at idle?

If it does it all the time after warming up, even at idle, then the lifter is the place to start.

[webco2]

Originally Posted by khutchinson

Everything was running fine until today on the way home from work. When cold the bike sounds fine but once it warms up there is a higher pitched pinging or knocking sound coming from the rear cylinder. I would think a bad rod bearing would make a noise up top all the time weather it was cold or not so I'm thinking possibly a push rod out of adjustment or a lifter not pumping up completely but still I am confused as to why heat would have anything to do with it.

Details:

80" EVO
Full top end rebuilt a couple months ago
Andrews EV27 Cam
K&N Cone Intake
Short Shot Exhaust

Lifter not fully pumped up would be my first guess.

[khutchinson]

All the time, yes. Checking lifter in a few. I'm hoping that's it. Cheap and easy.

[cavemanmikee]

are u using adjustable push rods? if it sounds like someone is constantly tapping on the engine-appears to be a lifter, also when u did top end, did u re-use oem pistons? or are u using high compression pistons? still sounds like a lifter? considering it is sensitive to temp. and amount of time running, lifter problems can fluctuate, problems in other areas are produce more consistent sounds

[khutchinson]

Originally Posted by cavemanmikee

are u using adjustable push rods? if it sounds like someone is constantly tapping on the engine-appears to be a lifter, also when u did top end, did u re-use oem pistons? or are u using high compression pistons? still sounds like a lifter? considering it is sensitive to temp. and amount of time running, lifter problems can fluctuate, problems in other areas are produce more consistent sounds

Reused OEM pistons.

Got the cam cover off. Revealed that the snap ring came off of the oil pump shaft so it wasn't pumping oil. Nice. Replaced 2 of the lifters and put everything back together. Now I get a tapping sound all the time weather it's cold or not. Going to replace the other 2 lifters as well and see if that helps. Beyond that I have no clue what could be causing the problem.