Name That Noise...
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Joined: Nov 2009
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From: Charleston, SC
Name That Noise...
The Bike: 2008 Street Glide with 21,000 miles.
Past Upgrades: Intake, exhaust, XIED's, SE Compensator (1 month ago to cure chatter when letting clutch out).
The Upgrade That I Think Started The Noise: Andrews 48h cam, SE adjustable pushrods with tubes (not tapered ones), new HD stock lifters. Rockers were never taken off.
The Noise: On a cold start, when it idles down you can hear a knock around the base of the rocker boxes on both cylinders, after about 2 minutes it goes away. Even when you rev it, you still won't hear it.
The main time when you hear it is when you take off, as the tach passes between 1800-2200, under light load. If you hold it at 2000 rpm you won't hear it, only under light load. When the bike is fully 180* warm, you won't hear it anymore or only very slightly. It may be happening at heavier loads but the exhaust is getting too loud at that point to be sure.
Rev it at a stand still, won't hear a thing hot or cold.
I was thinking it was the pushrods hitting the top of the tubes so I took down two of the tubes. The only marks I saw on the rods were a very slight ring around the rod in the finish about 1.5 inches from the top of the rod; looks more like packaging marks than anything else. What do rubbing pushrod marks typically look like? And, would a rubbing pushrod only happen when cold with load, at a certain rpm band?
It doesn't sound anything like spark knock...
My other thought is piston slap because it's worse when it's cold and only under load, but why would that start after a cam change?
I don't think it's serious or I would hear it all the time, just want to make sure I'm not tearing anything up.
Any ideas?
Past Upgrades: Intake, exhaust, XIED's, SE Compensator (1 month ago to cure chatter when letting clutch out).
The Upgrade That I Think Started The Noise: Andrews 48h cam, SE adjustable pushrods with tubes (not tapered ones), new HD stock lifters. Rockers were never taken off.
The Noise: On a cold start, when it idles down you can hear a knock around the base of the rocker boxes on both cylinders, after about 2 minutes it goes away. Even when you rev it, you still won't hear it.
The main time when you hear it is when you take off, as the tach passes between 1800-2200, under light load. If you hold it at 2000 rpm you won't hear it, only under light load. When the bike is fully 180* warm, you won't hear it anymore or only very slightly. It may be happening at heavier loads but the exhaust is getting too loud at that point to be sure.
Rev it at a stand still, won't hear a thing hot or cold.
I was thinking it was the pushrods hitting the top of the tubes so I took down two of the tubes. The only marks I saw on the rods were a very slight ring around the rod in the finish about 1.5 inches from the top of the rod; looks more like packaging marks than anything else. What do rubbing pushrod marks typically look like? And, would a rubbing pushrod only happen when cold with load, at a certain rpm band?
It doesn't sound anything like spark knock...
My other thought is piston slap because it's worse when it's cold and only under load, but why would that start after a cam change?
I don't think it's serious or I would hear it all the time, just want to make sure I'm not tearing anything up.
Any ideas?
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Fatboy Brian
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Dec 12, 2018 03:14 PM
