Mechanic's Stethoscope helpful? | GTAMotorcycle.com

Mechanic's Stethoscope helpful?

sburns

sburns

Well-known member
Hey riders!

So I am dealing with a new issue. The bike developed a ticking type sound, and from what I can guess the right side. Doing some research it could be something in the cam chest, lifters, or rocker bolts. Ugh..

Instead of ripping it all apart I have the idea of getting a stethoscope to help figure this out.

I have no experience using these, are they helpful?
Cost wise it's only $15 from either Princess Auto, or Canadian tire.
 
Don't fall prey to cognitive bias and convince yourself that it's something it's not - ticking noises can be anything from valvetrain noise, to an injector, and many things in between right down to something as simple as a failed exhaust gasket or pinhole exhaust leak somewhere. I could also be something more serious like piston slap.

Being able to narrow down exactly where the noise is coming from can be extremely helpful, so yes, a stethoscope can be a great tool indeed...but sometimes it still takes someone with some fairly in depth knowledge to properly interpret the outcome based on where the noise is coming from, as well as their experience telling them what the actual issue may be. Many people have fallen prey to their "diagnosis" on a problem and started throwing parts at an engine only to discover afterwards that the noise/problem is still there...IE, deciding that their ticking noise on a cylinder head is a bad injector, replacing it at great expense, only to discover afterwards (when they start it up and the exact same noise is still there) that it was actually a $2 leaky exhaust donut.
 
Ticking = Check your valve clearance adjustment first.
Crankshaft spins twice as fast as the valve drive, knowing that sometimes helps to diagnose the source of a mechanical noise.

Compression test is easy and can help to determine if one cylinder is having issues and not the other.
 
Not overly familiar with all the HD engine options, but I think his has hydraulic lifters, so no valve adjustments.

But yes, out of spec valves is a common source of ticking noises.
 
Thanks guys, going now to buy it. @PrivatePilot I get what you are saying at least it will help me narrow it down and I can open the suspect area to inspect before replacing anything.
 
;) you can never have too many diagnostic tools.

PrivatePilot said:
Not overly familiar with all the HD engine options, but I think his has hydraulic lifters, so no valve adjustments.

But yes, out of spec valves is a common source of ticking noises.
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I wondered about that :| but I bet there is still an adjustment.
 
adjustinghydrosolid.jpg
<- Pushrod length adjustment is the mechanical equivalent of a valve clearance adjustment.
 
If you can get access, a screwdriver between your ear and the part under investigation is as good or better than a stethoscope. Just dont get your hair sucked into moving parts.
 
GreyGhost said:
If you can get access, a screwdriver between your ear and the part under investigation is as good or better than a stethoscope. Just dont get your hair sucked into moving parts.
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;) the handle end goes towards your ear.
 
These twin cam Harley engines do tend to make some ticking noises. Just throwing it out there but have you possibly added lower fairings/different windshield for the change in weather? Different helmet? Different brand of oil? I'm only saying that as sometimes you change something and start to pick up different noises. It may have been there all along just you weren't hearing it.

Check for loose parts as well. Horn cover, shifters, brake pedal etc etc. I have had some stuff loosen up a bit and make what sounded like engine noise but was actually just a part rattling around that needed to be tightened up a little.
 
blackcamaro said:
These twin cam Harley engines do tend to make some ticking noises. Just throwing it out there but have you possibly added lower fairings/different windshield for the change in weather? Different helmet? Different brand of oil? I'm only saying that as sometimes you change something and start to pick up different noises. It may have been there all along just you weren't hearing it.

Check for loose parts as well. Horn cover, shifters, brake pedal etc etc. I have had some stuff loosen up a bit and make what sounded like engine noise but was actually just a part rattling around that needed to be tightened up a little.
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I know, they make lots of noises, but no I haven't changed anything and this noise developed between a oil change cycle. I know it does run a bit different between warmer weather and cooler but this is noticeably new noise. Also been there with "loose" stuff. I have had all kinds of things shake loose creating new rattle etc..
 
A big long phillips screwdriver is a cheap way to locate the source of ticking. Place it steel tip on the motor, the round part of the handle up to your ear. Sometimes easier than a stethoscope.

As far as diagnosing the problem, using a sound process of elimination is the best first step. As mentioned by others, you can get ticking from injectors, valve train, exhaust leaks, and on big twins you also have sympathetic vibrations all over the place - these change with the bikes condition, age, temperature etc.

When diagnosing ticks, I always cross things off in this order:
  • Exhaust leaks - check where pipe meets head. Usually more pronounced when cold.
  • Injector Noise - some noise if normal, if you have more than one injector, unplug one at a time to see if you have a noisy injector
  • Valve Train Noise - change O&F, check valve or pushrod adjustments.
  • Sympathetic vibrations - will come and go as you add RPM.
Your ride looks like an ex cop bike. I'm not an HD expert but I think cop bikes are often fitted with stage II high lift cams, their steeper slope will make the valvetrain tick if push rods are out of adjustment.
 
Mad Mike said:
A big long phillips screwdriver is a cheap way to locate the source of ticking. Place it steel tip on the motor, the round part of the handle up to your ear. Sometimes easier than a stethoscope.

As far as diagnosing the problem, using a sound process of elimination is the best first step. As mentioned by others, you can get ticking from injectors, valve train, exhaust leaks, and on big twins you also have sympathetic vibrations all over the place - these change with the bikes condition, age, temperature etc.

When diagnosing ticks, I always cross things off in this order:
  • Exhaust leaks - check where pipe meets head. Usually more pronounced when cold.
  • Injector Noise - some noise if normal, if you have more than one injector, unplug one at a time to see if you have a noisy injector
  • Valve Train Noise - change O&F, check valve or pushrod adjustments.
  • Sympathetic vibrations - will come and go as you add RPM.
Your ride looks like an ex cop bike. I'm not an HD expert but I think cop bikes are often fitted with stage II high lift cams, their steeper slope will make the valvetrain tick if push rods are out of adjustment.
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Thanks mike. Yes you are correct it is a ex cop bike. But as far as I know the only difference is the stator motor, otherwise it is same as civilian.
 
sburns said:
Thanks mike. Yes you are correct it is a ex cop bike. But as far as I know the only difference is the stator motor, otherwise it is same as civilian.
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I had to retrieve a buddy from a road side stunting thing about a month ago, I asked the cop how he managed to catch a car doing 165 on a cop HD. He said they do 175 and are equipped with HD stage II kits. I have no way of knowing whether that's true or not.
 
Mad Mike said:
I had to retrieve a buddy from a road side stunting thing about a month ago, I asked the cop how he managed to catch a car doing 165 on a cop HD. He said they do 175 and are equipped with HD stage II kits. I have no way of knowing whether that's true or not.
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Wouldn't surprise me....might have had my VTX up to 159KPH (GPS) on a certain section of (non Canadian) road this past summer where I may or may not have actually been exceeding the speed limit by that much anyways... that's all I'm saying LOL. :whistle:

Was trying to hit the magic 162KPH (100MPH). Had a 25-30 MPH headwind and I just ran out of horsepower and couldn't do it. But my bike is only a 1300....

#vtwinproblems
 
Mad Mike said:
I had to retrieve a buddy from a road side stunting thing about a month ago, I asked the cop how he managed to catch a car doing 165 on a cop HD. He said they do 175 and are equipped with HD stage II kits. I have no way of knowing whether that's true or not.
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Hmmm to my knowledge they don't come with any engine mods, no one in the HD police forums has mentioned it either.
But who knows they could always order them with extras. I've had mine up to 150 kph without much issue and it's just a 103 (1690cc)
 
I got the Sthethoscope, neat little tool. But being a HD it makes a bunch of normal chattler and sounds. I think I am getting close to figuring out where it is coming from. It's definitely different then before, I just did a run (photo tag) tonight just to see how it was running. Much louder then before and more clunky/ticking noise. I know that might not seem much different with it being a HD engine, but something is up.
 
sburns said:
I got the Sthethoscope, neat little tool. But being a HD it makes a bunch of normal chattler and sounds. I think I am getting close to figuring out where it is coming from. It's definitely different then before, I just did a run (photo tag) tonight just to see how it was running. Much louder then before and more clunky/ticking noise. I know that might not seem much different with it being a HD engine, but something is up.
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If something is changing fast enough to notice, I recommend parking it until you figure out the problem. Little problems can turn into big problems quite quickly. On a bike, this not only costs you money, it may get you hurt.

A few days ago someone posted a video on a facebook group asking for help with their car. They had changed the oil and filter and it sounded like crap after. After running for ~15 seconds, the car gave an oil pressure warning. This bright spark kept repeating the test to see if anything changed. I shudder to think what the inside of that engine looks like after running without oil flow for minutes.
 
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