Engine noise - crackling sound starts at around 3k -

DavidReeves

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Oct 20, 2012
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03 with 90k km - recently noticed a distinct crackling sound when engine begins to warm up - mostly under acceleration and slightly under deceleration - disappears when clutch engaged & does not make an appearance unless under load starting around 3k - tried to replicate sound seated on bike on centre stand & slightly dragging rear brake - nothing - pulled Tupperware & checked for rattles, loose fasteners in the exhaust etc - suggestions? Could cam chain tensioner be going and only under load when cam shaft slightly deflects would the chain make the noise?

Attached audio link
https://www.youtube.com/watch?v=e-Nlt8a-48U&feature=youtu.be
 
Last edited:
Rubberdarts

Rubberdarts

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You have no cam chain tensioner on 1300, gear driven cams, that's the whine sound they all make. Try to isolate if this is driveline or engine first. There are some posts on driveshaft and rear bearings which may be worth looking at. Good luck. Keep us all posted with progress.
 
BakerBoy

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(Rubberdarts, the 1100 is belt driven gears driving the cams. The 1300 has chain driven cams--no gears)

DR, it is not likely the chain or chain tensioner--there has been only one defective one (in a new ST1300, happened within first couple thousand miles) that I can recall hearing about. There's a thread on this forum somewhere for it. But, I'm wondering about the clutch. If you're up to speed and pull the clutch lever, retaining the high RPM's, what happens?
 
Byron

Byron

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There are in fact two cam chain tensioners on the ST1300, one on each side. They aren't adjustable but spring loaded and auto adjust. Right side in in the valley below the throttle bodies and the left is near the bottom of the head and visible. The gears you mention are adjustable from the front but the factory service manual warns to leave them alone unless they need adjustment because of a disassembly. Once set at the factory they should be good for the life of the engine.

Sorry, no help on the noise you are hearing.
 
dduelin

dduelin

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DavidReeves said:
03 with 90k km - recently noticed a distinct crackling sound when engine begins to warm up - mostly under acceleration and slightly under deceleration - disappears when clutch engaged & does not make an appearance unless under load starting around 3k - tried to replicate sound seated on bike on centre stand & slightly dragging rear brake - nothing - pulled Tupperware & checked for rattles, loose fasteners in the exhaust etc - suggestions? Could cam chain tensioner be going and only under load when cam shaft slightly deflects would the chain make the noise?
Click to expand...
Is this bike new to you or a new noise after many miles together?
 
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DavidReeves

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I've put on about 30k - first noticeable a short while ago - I'm very familiar with the st's traditional mechanical symphonies
 
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DavidReeves

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No noise when the bike is stationary or at slow speeds - clutch engages smoothly - but it would explain the crackling noise if there is debris bouncing around in there
 
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DavidReeves

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Low hanging fruit picked - valve clearances all within spec - cam chain & adjusters look ok - guides are intact - tensioner is taking up slack - hmm
 
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DavidReeves

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Found the problem - Thanks for the responses - also found out checking valve clearances and checking the right side cam tensioner with air box etc removed is not as intimidating as I thought - the noise emanated from a stock Honda headlight connector with the 3 tabs on the back to access wiring that suddenly had a little rock bouncing around inside and clanking around on the sub frame - I had bypassed the plugs to hook up my headlight modulator - :eek:)! Took a while.
 
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DavidReeves

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Oct 20, 2012
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PS - even had a motocycle mechanic listen to the audio file - said it was the cam chain tensioner & "all these Hondas have inferior tensioners" :eek:)
 
Byron

Byron

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Glad you were able to sort out the issue, nothing worse then having something off and not being able to find the source.

Good job!
 

dc112675

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Dec 5, 2014
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Hobbs, NM
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2004 ST1300A
DavidReeves said:
Found the problem - Thanks for the responses - also found out checking valve clearances and checking the right side cam tensioner with air box etc removed is not as intimidating as I thought - the noise emanated from a stock Honda headlight connector with the 3 tabs on the back to access wiring that suddenly had a little rock bouncing around inside and clanking around on the sub frame - I had bypassed the plugs to hook up my headlight modulator - :eek:)! Took a while.
Click to expand...
I still laugh at my dad...about 25 years ago he installed some speakers in the back of his extended cab truck. For a year after he kept hearing a knocking noise when he turned. After several diagnosis and tearing the truck apart, he located the sound...he took off the speaker and found a hammer standing on its head! Every time he turned the handle banged against the metal!
 
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