2016 America LT annoying rattle

[Phoelix1]

May have posted this before. I have the 2016 America LT with 10,000 miles that’s been a great machine, but has developed a “rattling” sound primarily at 65 mph (indicated) and 4th gear. The rattle dossipates when shifted into 5th gear. I have detected the rattle at 55 mph in 3rd gear, and a tiny bit at 75 mph in 5th gear.This has driven me nuts trying to find the source. It sounds a lot like tin foil being rubbed together, or a few bb’s being shaken in a coffee can. Not loud, but just loud enough that irritates me. I’ve taken off the windshield, swapped exhaust systems, replaced the chain and adjusted the chain per batum from the manual, adjusted (shimmed) valves, checked cam chain tensioner, removed saddlebags, and inspected the bike meticulously for anything loose, but the rattle persists.
I thought maybe it was coming from the speedometer and disconnected it,but bike wouldn’t do ANYTHING, and gave a “check engine” light, which was rendered by disconnecting the battery. I’ve asked our local Triumph service manager, Triumph Tech support, all of which have never heard of this rattle on ANY bike. I’ve just learned to live with it, and figured this was why the bike was traded in.

 

[Qship]

Sounds like it's at a certain RPM as you say it happens in all of the upper gears, but at various speeds. Could you imitate it on a stand with the rear wheel in the air(bike properly tied down of course). At least if it's stationary you may be able to pinpoint where it's coming from. If not on a stand then on a dyno maybe where the engine will be under load like out in the real world.

 

[Phoelix1]

Sounds like it's at a certain RPM as you say it happens in all of the upper gears, but at various speeds. Could you imitate it on a stand with the rear wheel in the air(bike properly tied down of course). At least if it's stationary you may be able to pinpoint where it's coming from. If not on a stand then on a dyno maybe where the engine will be under load like out in the real world.

I have ran the bike on my bike jack, and using a stethoscope. Most noise coming from front sprocket, but rattle sound was not conclusive. Rattle REALLY showed itself riding home from work last night. 3rd gear up thru 50-55 mph. Not so much in 4th gear now. Freakin’ !

 

[Qship]

I got nuttin' else.
Hope you can find it without big expense or loss of sanity.

 

[DirtieGirtie]

Chains and sprockets act/sound very different when under load than when they are not. On another forum for a different brand a guy would hear a noise while accelerating or running at a constant speed, but coasting down hill or decelerating (engine braking only) would not create the same noise. I've had similar issues on outboard engines... they run perfect in the driveway without a load, but run them in the water under load and they could act/sound very different. I only bring it up so you can get more precise info on when it does or does not make the noise. That will help diagnose.

If you think your front sprocket has rounded teeth or something, it's very inexpensive to replace. I just ordered one of these: https://www.amazon.com/gp/product/B001AVS7DK/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
I haven't replaced mine yet, but I'm guessing it will be just as easy as it has been on other brands of bikes. Side note: if you want more low speed acceleration, now is a good time to drop a tooth on the front sprocket, and if you want to lower your cruising RPMs on the highway then get one with an extra tooth. Or stay stock, your choice. Make sure you adjust your chain tension per the manual after replacing the sprocket.

 

[Phoelix1]

Chains and sprockets act/sound very different when under load than when they are not. On another forum for a different brand a guy would hear a noise while accelerating or running at a constant speed, but coasting down hill or decelerating (engine braking only) would not create the same noise. I've had similar issues on outboard engines... they run perfect in the driveway without a load, but run them in the water under load and they could act/sound very different. I only bring it up so you can get more precise info on when it does or does not make the noise. That will help diagnose.

If you think your front sprocket has rounded teeth or something, it's very inexpensive to replace. I just ordered one of these: https://www.amazon.com/gp/product/B001AVS7DK/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
I haven't replaced mine yet, but I'm guessing it will be just as easy as it has been on other brands of bikes. Side note: if you want more low speed acceleration, now is a good time to drop a tooth on the front sprocket, and if you want to lower your cruising RPMs on the highway then get one with an extra tooth. Or stay stock, your choice. Make sure you adjust your chain tension per the manual after replacing the sprocket.

Both Sprockets appear new. There’s only 10,000 miles on the bike!

 

[Phoelix1]

Spent most of the day taking the chain off and cleaning it thoroughly along with both sprockets, all meticulously cleaned and lubed. Test ride fail, rattle still present. Removed front disc brake pads as well as anti rattle clip, test ride fail, rattle still present. Removed factory windshield, simply couldn’t hear ANYTHING at 35 mph due to wind noise.
While re- installing the windshield, discovered tiny sign of fretting on lower fork of windshield brackets (copper in color).
Really didn’t expect this fretting to be the culprit, but coated hook and fork with molybdenum anti-seize as good measure, then left the bike sitting until a ride to the poolroom later that night. Absolutely ZERO chatter at all speeds and gears. The windshield brackets appear to be the culprit if any of you ever have this nuisance rattle.

 

[Rocky]

Glad you found it
Thanks for passing this along.

 

[CarlS]

Excellent!! So glad you solved the problem.

 

[Hurtle]

Who'da thunk it, eh? Something so obscure? Glad you found it, mate. Persistence pays off in the end.

 

[sikatri]

Good sleuthing!

 

[Xavier]

May have posted this before. I have the 2016 America LT with 10,000 miles that’s been a great machine, but has developed a “rattling” sound primarily at 65 mph (indicated) and 4th gear. The rattle dossipates when shifted into 5th gear. I have detected the rattle at 55 mph in 3rd gear, and a tiny bit at 75 mph in 5th gear.This has driven me nuts trying to find the source. It sounds a lot like tin foil being rubbed together, or a few bb’s being shaken in a coffee can. Not loud, but just loud enough that irritates me. I’ve taken off the windshield, swapped exhaust systems, replaced the chain and adjusted the chain per batum from the manual, adjusted (shimmed) valves, checked cam chain tensioner, removed saddlebags, and inspected the bike meticulously for anything loose, but the rattle persists.
I thought maybe it was coming from the speedometer and disconnected it,but bike wouldn’t do ANYTHING, and gave a “check engine” light, which was rendered by disconnecting the battery. I’ve asked our local Triumph service manager, Triumph Tech support, all of which have never heard of this rattle on ANY bike. I’ve just learned to live with it, and figured this was why the bike was traded in. View attachment 47810View attachment 47810

 

[Xavier]

Piston slap?

 

[Qship]

Piston slap?

Member found cause. The older 865cc Bonnevilles engines are not known for piston slap.