2015 R1200RT detonation

[RA John]

My bike has what sounds like detonation between idle and 3000 rpm. The sound occurs while accelerating to 3000 rpm (which is the low end of the rpm range I normally use). It disappears under steady state and trailing throttle use. I consider how the sound changes with throttle a classic description of light throttle detonation.

 

My dealer has encouraged me to use Heet fuel system additive at a 1 oz per gallon ratio without an explanation how it will effect detonation. Use of Heet has not changed the sound that I hearing. Have any of you heard to sound and have you found a cure?

 

Thanks,

 

--John

[dirtrider]

Afternoon John

 

You might have a little spark knock but I highly doubt you have a detonation issue.

 

If you do have combustion detonation then you won't have to worry about it for very long as your engine will be VERY/VERY short lived.

 

Your engine has spark knock sensors so a little burst spark knock on throttle up can be normal & non harmful.

 

[FrankBrown]

Afternoon John

 

You might have a little spark knock but I highly doubt you have a detonation issue.

 

If you do have combustion detonation then you won't have to worry about it for very long as your engine will be VERY/VERY short lived.

 

Your engine has spark knock sensors so a little burst spark knock on throttle up can be normal & non harmful.

 

There is no anti-knock technology in the liquid cooled boxer engine....make sure you're using 'high test' gasoline.

[strataj]

Afternoon John

 

You might have a little spark knock but I highly doubt you have a detonation issue.

 

If you do have combustion detonation then you won't have to worry about it for very long as your engine will be VERY/VERY short lived.

 

Your engine has spark knock sensors so a little burst spark knock on throttle up can be normal & non harmful.

 

There is no anti-knock technology in the liquid cooled boxer engine....make sure you're using 'high test' gasoline.

 

Are you 100% sure, I was told by a reliable source the GS had it, I don't think the RT does.

 

Jay

[mneblett]

Are you 100% sure, I was told by a reliable source the GS had it, I don't think the RT does.

I believe your reliable source is mistaken -- BMW has been talking up their eliminating the "need" for knock sensor(s) and twin-spark since the wethead was introduced. No knock sensor on the GS or RT.

[Skywagon]

what grade fuel are you using?

[strataj]

Are you 100% sure, I was told by a reliable source the GS had it, I don't think the RT does.

I believe your reliable source is mistaken -- BMW has been talking up their eliminating the "need" for knock sensor(s) and twin-spark since the wethead was introduced. No knock sensor on the GS or RT.

 

If you where there, IBMWR Blitz 2 Branson 2014 you would of believed it too.

 

Jay

[FrankBrown]

Afternoon John

 

You might have a little spark knock but I highly doubt you have a detonation issue.

 

If you do have combustion detonation then you won't have to worry about it for very long as your engine will be VERY/VERY short lived.

 

Your engine has spark knock sensors so a little burst spark knock on throttle up can be normal & non harmful.

 

There is no anti-knock technology in the liquid cooled boxer engine....make sure you're using 'high test' gasoline.

 

Are you 100% sure, I was told by a reliable source the GS had it, I don't think the RT does.

 

Jay

 

Yes, I'm 100% sure. What the GS has that the RT doesn't is the ability for the dealer to reprogram the ECU to run on 87 octane for those countries where 'high test' is an unrealized dream.

[Bill_R]

what grade fuel are you using?

 

GS Rider's Manual specifies 89 AKI, which they call "Super unleaded" (E10).

[ScottT]

I knew the lack of knock sensors would result in detonation problems for some owners. It's something I am very glad is on my 2005 RT because it gives me the option to use low test fuel without the risk of engine damage. The computer is able to deal with it, with the only side effects being a slight reduction in performance and fuel economy. This is one place where the LC motor has gone backwards. It raised a red flag with me when I first found out about it a year ago. Personally I find it unacceptable that BMW has removed this protection. I'm sure they did for cost reasons but it locks an owner into having to use high test, which increases to cost of ownership. I regularly run mid-grade on my RT because there's no difference in fuel economy vs. high test. I don't run low test because the drop in fuel economy costs more than the drop in price between low and mid grade. And finally there's the situation where the only fuel available is low grade. In the states it doesn't happen too often but I've run into situations in the middle of nowhere out west where low grade is to only gas they're selling.

[RA John]

Thanks for the replies.

 

-- dirtrider; can you define spark knock?

 

-- Frank Brown, per my dealer both the GS and RT both have knock sensors.

 

Others; I use the highest octane available. My favorite station has 91 octane, unleaded, non-oxygenated fuel which I use.

 

I am very aware of the damage detonation causes and that's why I am concerned. As I mentioned earlier I can roll the sound in and out by varying the throttle position and load. I talked to the dealer and he hasn't had detonation problems with the RT. He says that they can make cam chain noise at low rpm but the noise shouldn't be throttle position sensitive. If the weather holds later in the week I'll take a ride to his shop (about 1.5 hours away) and have him ride/listen to it and see what he thinks.

 

--John

[AnotherLee]

From wikipedia:

Various monitoring devices are commonly utilized by tuners as a method of seeing and listening to the engine in order to ascertain if a tuned vehicle is safe under load or used to re-tune a vehicle safely.

Is this true? If so, get thee to a tuner!

[FrankBrown]

"-- Frank Brown, per my dealer both the GS and RT both have knock sensors."

 

If your dealer is referring to the liquid cooled boxer engine, he is wrong.

[Skywagon]

Alternative point of view.. Don't think the gas bill is going to make too much of a difference. I always use top fuel. Lets say you ride 12,000 miles a year on a new LC....suspect that is really high. Let's say you only average 45MPG which is really low, and let's say there is $.30 per gallon more for high versus low test....Well that's about $80/year. If I calculate for me, I average 6000 miles a year, bike is averaging 48MPG(more on the highway), and I used $.30 as filled up today and that was the difference. Thats $37/year. Just food for thought. I suspect in some places price differential is greater, but all in all, not worth the risk of detonation, preignition, etc.

[realshelby]

I always run the highest octane the pump offers. I do get a noise at lower rpms as I accelerate lightly that sounds an awful lot like pinging. I can hear it plainly without earplugs, less so with them in. It has never changed but always does it under the same conditions. I do not hear anything that bothers me under heavier load and higher rpms. I don't know if this is the noise everyone is talking about? If it is very light spark knock I know it won't hurt it, but why does it do it?

[ScottT]

You know that the manual says 89 AKI (anti-knock index) is the fuel of choice for your bike, right? That's mid-grade. Running 91 or higher is a waste of $$$. The AKI rating is what is displayed on most pumps in the US and Canada.

 

Recommended fuel quality Super unleaded (max. 10 % ethanol, E10)

89 AKI (95 ROZ/RON)

[Skywagon]

Yep...familiar with the spec.

 

Super unleaded (max. 10 % ethanol, E10) (Right out of manual)

89 AKI (95 ROZ/RON)

89 AKI

 

Aspreviously posted the 91 I buy and the no knock I get is worth the $37/year differential. My old airhead R100RT would knock no matter what adjustments you made to timing, carbs,plugs, jetting, etc. It would not knock with high test.

 

Fuel cheap....Engine expensive.

[RA John]

realshelby--

 

Your comment makes it sounds like you have the same or similar noise. I am familiar with what occurs (and how it sounds) during normal combustion, detonation and pre-ignition.

 

What is your definition of "spark knock"?

 

Thanks,

 

--John

 

 

[realshelby]

 

What is your definition of "spark knock"?

 

Thanks,

 

--John

 

 

Spark knock is that light pinging sound when accelerating mildly or pulling a hill in a gear where rpms are maybe lower than optimal. Not damaging in the way all out detonation is. I have had owners manuals stating light pinging under load or acceleration is ok.

 

My RT has a metallic sound like steel balls rattling around when I accelerate lightly through the gears in the lower rpms. Since I always have run premium grade (93 around here) I don't have any better fuel to test with. I just might run it low and put a couple gallons of 87 octane in it next time and see if the sound is the same.

[mneblett]

My RT has a metallic sound like steel balls rattling around when I accelerate lightly through the gears in the lower rpms.

I have the same sound, but only when the engine is cold, like starting in my office garage, stopping to use the access card to exit, and then going up the ramp to ground level. Also using 93 octane.

[realshelby]

My RT has a metallic sound like steel balls rattling around when I accelerate lightly through the gears in the lower rpms.

I have the same sound, but only when the engine is cold, like starting in my office garage, stopping to use the access card to exit, and then going up the ramp to ground level. Also using 93 octane.

 

I wouldn't be surprised if this is not very common if not in all of them. May not be spark knock/detonation at all, I just don't know. Mine does it warm also. Since it has not changed in 10,500 miles I am not staying awake at night worrying.

[RA John]

dirtrider, realshelby and mneblett--

 

If the "spark knock" your hearing changes with throttle position you are hearing detonation. I know in the past some manufacturers have said light detonation is acceptable but it is never OK in my book. I hope that the dealer is able to diagnose the sound and fix it.

 

Thanks for the input,

 

--John