Help with engine noise under load
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Road Captain
Joined: Feb 2009
Posts: 671
Likes: 5
From: D.C suburbs
Help with engine noise under load
I have a noise under load at a out 2k rpm and up but only when tire moving. I can't replicate when idling, in or out of gear. It sounds like an exhaust leak, or air leak with metal high pitch rattle. I can hear it on the highway when it's under load. If I let off the gas, I can't hear a thing. I had the rear come up low compression, rings not sealing but was torn down and fixed. The front was fine so I didn't touch it as recommended by a builder. WOT I hear what sounds like gravel in the front cylinder. I had the bike dyno'd the end of last year but the noise started May this year, tuner said I would not need to adjust the tune after fixing the rear cylinder. I tore down the cam chest but stopped short of checking out the oil pump, pressure has been fine. I have an old tune from FM that I was going to try and see if the gravel noise is a detonation problem. Build is an FM 107, bike pulls and rides like nothing is wrong.
Road Captain
Joined: Dec 2012
Posts: 577
Likes: 20
From: Reno
Another Rockout Rocker Locker Customer... Spend the 15 bones on amazon... buy 8 new bolts, new rocker cover gaskets from the moco (for insurance/assurance), and the oil filter kit (filter element, 2 gaskets for each jug) and that may just solve your problems.
Stellar HDF Member
Joined: May 2015
Posts: 2,100
Likes: 307
From: mid Michigan
If it is detonation should be able to tell by looking in spark plug holes with small flex light. Tops of pistons will look like they have been sand blasted. Should be signs of it on spark plugs as well but harder to tell.
Last edited by xcbullet; Oct 19, 2015 at 05:40 AM.
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Road Captain
Joined: Feb 2009
Posts: 671
Likes: 5
From: D.C suburbs
Oh yeah she has been on a lift a lot since May. The noise completely goes away if no throttle is applied. Clutch in or out. I get It only under load
Tourer
Joined: Jul 2010
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From: Belfast, N. Ireland
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From: Central Fl
I have a noise under load at a out 2k rpm and up but only when tire moving. I can't replicate when idling, in or out of gear. It sounds like an exhaust leak, or air leak with metal high pitch rattle. I can hear it on the highway when it's under load. If I let off the gas, I can't hear a thing. I had the rear come up low compression, rings not sealing but was torn down and fixed. The front was fine so I didn't touch it as recommended by a builder. WOT I hear what sounds like gravel in the front cylinder. I had the bike dyno'd the end of last year but the noise started May this year, tuner said I would not need to adjust the tune after fixing the rear cylinder. I tore down the cam chest but stopped short of checking out the oil pump, pressure has been fine. I have an old tune from FM that I was going to try and see if the gravel noise is a detonation problem. Build is an FM 107, bike pulls and rides like nothing is wrong.
What yr and type of HD is having the problem?
Change to a different gas station, make sure there is no ethanol in their fuel. Maybe a bit of octane booster in the next tank if a different gas station doesn't help. If it is a detonation related noise it should change the sound. Is the compression in the two cylinders even within spec?