BMW S1000RR Forum banner
  • Hey everyone! Enter your ride HERE to be a part of JULY's Ride of the Month Challenge!
1 - 8 of 8 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
Specs:
2020 - Sport (all options other than the carbon wheels)
Austin Racing GP3 full exhaust
Sprint road filter
BrenTuning Stage 1
- rest are cosmetics

Symptoms:
1. Shortly after installing my GP3 exhaust I noticed that when cruising between 4-6k RPM there would be a loud, what I can only describe as howl, that would accompany the rev of the engine (regardless of gear). Once I hit 7k it would go away. At first it was very intermittent but now it happens every time I ride. This howl is louder than my exhaust, and if you know anything about the AR full exhausts, they are loud.

2. I had noticed that my left handle (where you hold on) was loose and twisted about 16th of a turn, thought it was odd, but no big deal. Today I am feeling a very pronounced increase in vibration to the handle bars.

Question:
1. Anyone else experience this? I searched the forum and found 1 or 2 others, but they were from several years ago and no one really answered either of them.
2. Does this motorcycle come with a knock/vibration sensor that will alarm when this reaches a critical level? Should I be worried?

Any thoughts would be much appreciated.

Thank you.
 

·
Registered
Joined
·
1,751 Posts
Every part individually has a resonant frequency, and every SYSTEM has a resonant frequency. When a bunch of the individual parts have the same or similar resonant frequency, it's amplified in the system. It can manifest only as sound, or by sound and a vibration thru the bars (or anything else). This is partially due to weight, and also to stiffness etc., a whole range of factors. I noticed on my 2015 that when I put the Yosh R55-LE on, the vibe in my bars, the right bar especially, dropped quite a bit at the 4-5k rpm range where it buzzed pretty badly. I was happy with this added and unexpected bonus. For the noise, not much can be done besides baffles etc. For the bar vibes you can try different bar ends and/or internal damping. You could also wrap the exhaust with Thermo-Tec wrap and that might help. Also, check all your mounting points/bolts and make sure they're all tight.

Best of luck!
 

·
Registered
Joined
·
97 Posts
BrenTuning Stage 1

1. Shortly after installing my GP3 exhaust I noticed that when cruising between 4-6k RPM there would be a loud, what I can only describe as howl, that would accompany the rev of the engine (regardless of gear).

Any thoughts would be much appreciated.

Thank you.
Have you contacted brentune?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
Every part individually has a resonant frequency, and every SYSTEM has a resonant frequency. When a bunch of the individual parts have the same or similar resonant frequency, it's amplified in the system. It can manifest only as sound, or by sound and a vibration thru the bars (or anything else). This is partially due to weight, and also to stiffness etc., a whole range of factors. I noticed on my 2015 that when I put the Yosh R55-LE on, the vibe in my bars, the right bar especially, dropped quite a bit at the 4-5k rpm range where it buzzed pretty badly. I was happy with this added and unexpected bonus. For the noise, not much can be done besides baffles etc. For the bar vibes you can try different bar ends and/or internal damping. You could also wrap the exhaust with Thermo-Tec wrap and that might help. Also, check all your mounting points/bolts and make sure they're all tight.

Best of luck!
Thank you. I just found some threads where the AR exhaust had ripped through the wall at the bracket welds. I am going to check on these next. I took the howl as an exhaust leak to begin with, so this may make sense.

Have you contacted brentune?
I have not. From what I can tell that dude doesn't have a lot of patience, so I thought I'd bounce the forum before I hit him up.

Thanks for your replies, guys. Much appreciated.
 

·
Registered
Joined
·
1,751 Posts
Good deal. When you find a sudden new vibration/noise, something has broken or come loose.

When you say "threads", you mean website threads (posts) vs ACTUAL threads, right? No offense, but, from what I've seen, AR exhausts aren't the best quality, so...
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #6 ·
Good deal. When you find a sudden new vibration/noise, something has broken or come loose.

When you say "threads", you mean website threads (posts) vs ACTUAL threads, right? No offense, but, from what I've seen, AR exhausts aren't the best quality, so...
I don't work for AR, so no offense taken. I am finding all this out after the purchase.

By threads, I mean forum threads here.

Is there some kind alarm that sounds when vibration becomes a critical issue, or will it just blow?
 

·
Registered
Joined
·
1,751 Posts
I don't work for AR, so no offense taken. I am finding all this out after the purchase.

By threads, I mean forum threads here.

Is there some kind alarm that sounds when vibration becomes a critical issue, or will it just blow?
The "alarm" IS the increased vibration. The engine isn't going to just "blow" (unless you're z00 - LOL), there is a rev limiter to prevent that and the only way to blow the motor is to downshift at too high a rev and mechanically overrev it. If there is a major crack in your exhaust, it could FAIL catastrophically and come completely loose from the bike, possibly causing a crash. Cracks ALWAYS get bigger, and the bigger they get, the faster they get bigger. It's a vicious cycle accelerating to total failure.
 

·
Premium Member
Joined
·
102 Posts
OP: for your #2 issues, this maybe your issue/fix:
 
1 - 8 of 8 Posts
Top