Hi all,

I have a rattling, pretty high pitch, sound coming from left side when accelerating even so lightly. Let's say I am in first, second or third gear at 2.500-3000 rpm, giving her just a little throttle, then it rattles, very specifically on the left side. (Sounds like small marbles in a can.)

I do no get any knockcounts doing this, but if I pull the throttle fast, I can produce them when the engine and weather is hot, and then around 2.750 rpm and MAP 50 kph on the front cylinder. (I have pulled 2-4 degrees timing and also increased the VE:s there.)

As the sound is present, wether cold or warm engine, I find it hard to believe the sound comes from knocking.

What could it be? It rattles at light load as described. (Never, standing still at neutral.)

I think I had this sound even before big bore a year ago, but not really sure. It is louder now, anyway.

Could it be the system of levers connecting to the transmission? Or the compensator? Or the rocker arms?

Thanks in advance for your hints here.

Best Regards

P. S. I checked the pushrods. They look fine.

 

Year? Model?

 

Oh, sorry. Thought it was visible in my signature.

It is a Dyna 2006, Andrews 26h (installed 2022), bored to 98 ci (2023), MLS 0.40, lightly milled heads, corrected compression 1:9.2, adjustable pushrods, S&S lifters and forward controls. Yes, it also has manual compression releases. (Can it be that one is leaking when there is pressure?)

 

Upon unscrewing the compression release valves, I found the rear one being almost fingerlose. The threads on the valves were full of loctite, I think green loctite, because it was hard as glass and was neither red nor blue.

I cleaned the valves and the threads with Seafoam and compressed air, also I cleaned the threads in the cylinder heads with tops and Seafoam. Then I lubed them with Lucas Assembley Lube (containing zink an moly) and torqued them to 15 Nm. On the little test I did on the street, I could hear no noise.

I have a flat tire. As soon as I have fixed it. I will test more. I hope booth the rattle at load at 2.500 rpm, as well as the MAP 30-40 kpa surging, which I have experienced for quite a long time, were due to the inadequately torqued, and consequently, leaking compression releases.

I saw on the net that there is ceramic anti-seize which is good for steel and aluminum. I may use that I think. (Copper is not good for aluminium, I have heard.)

But perhaps Lucas Assembley Lube with zink is ok. Not sure. Read that they use zink lube for spark plugs on aeroplanes.

Anyone here that knows?

 

It might have been that.. I hope it was and the mystery is solved.

 

Thanks a lot.

 

Chasing rattles on a Harley? A person could end up in the nervous hospital. I had a rattle one time. Chased it all over. Turned out to be a worn out rubber muffler insulator on the left muffler.

 

Left side…shifter linkage possible could be a likely suspect.

 

I would also look around the Y on the exhaust and the mounting brackets,, if that didn't fix it. But as said can be a million things,

 

^^^yup, drove me crazy until I found it