Headers bright red!

[rdfarr]

Question: I recently traded my R11RS for a 4-plug R1150RT. Since I hadn't ridden it for a couple of weeks, I cranked it up and ran it on the fast idle to charge the battery. I kept an eye on the temperature gauge, and it stayed within normal limits. However, after about 5 minutes or more, I happened to look at the headers and they were bright cherry red! I immediately shutdown the engine. Is this normal? I never had anything like this happen to my old RS.

[Al Navecky Jr]

YES this is normal. My 2000 RT did it.

[DEF]

Read your manual. BMW recommends against starting and idling the boxer engine for just this reason....extreme heat in headers and CAT. You could start a fire doing what you did.

 

Charge your battery with a battery charger.

[codinn]

All air cooled motorcycles really only cool when there is air moving over the hot parts. That requires either

a) riding it at more than 5 mph

b) a REALLY windy day or

c) a BIG fan directly blowing across the parts needing to be cooled.

 

Sitting in your garage, on the side of the road, in a parking lot, etc. while running will result in the kind of heat buildup you described.

 

Leave it running a bit longer and plastic parts near to the headers will start to melt. ($$$)

 

Longer still and you risk a fire.($$$$$)

 

If you need to charge the battery you might want to consider either a battery charger or going for a 20 minute spin around the neighborhood.

[RFW]

As others have said, this is normal. The manual also has some words to say about it too. But the most important reason for not running the bike at idle ro an extended period is plain common sense. This is a BIG air cooled engine. Where is your cooling at idle?

 

One reason why these bikes do this and your old one didn't is the emission conrol system. To help meet emissions, your spark is retarded at idle. More heat ends up being blown out the exhaust with retarded timing..

 

Bob.

[motoguy128]

Like mentioned above get a battery charger. I keep my bikes plugged in whenever I pull it into the garage.

 

have a Battery Tender Jr (looks like a large AC adapter... well basically it is) and it can recharge as well as keep the battery "topped off", whci hwill extend battery life.

 

I've used this charger on 4 different bikes and never had a dead battery, never removed the batteries in the winter with temps under 0F and some battieries were over 4 years old.

[Lineareagle]

I was told by my mech that running at fast idle causes the normal system to be bypassed and the fast idle lever to pump excess fuel into the heads causing very rapid heat up.

His admonition:

NEVER run the bike on fast idle for more than the time it takes to start and maintain a smooth idle at 1000 rpm.

Basically that would mean about 30 seconds here in the north land at 5 C. my experience at least.

BTW shutting down the bike right away was probably not a great thing to do as the oil in the cylinders would be so thin there would be little lubricity left. The best thing would to be kill the fast idle, get on the bike and slowly ride around getting the temp down slowly.

[No_Twilight]

I was told by my mech that running at fast idle causes the normal system to be bypassed and the fast idle lever to pump excess fuel into the heads causing very rapid heat up.

 

Well, the term "mechanic" doesn't mean you understand the bike. All you need is a shingle and you can start charging people to work on their bike. All the fast idle does is open the throttle a little. Once you adjust your throttle cables or do a throttle balance you'll see that it is just another cable down to the throttle plate...

 

but his advice is pretty close to right. Start it on fast idle, ride off, turn off the fast idle before you get to the first curve where it will make you go faster than you want. If you forget to turn it off, it is no problem as you'll figure it out at the first light where the idle is now 3500 rpm. The only real risk, so long as you're riding and therefore providing cooling, is being unable to roll off the throttle as much as you want to going into a slow curve. I have a slow curve 2 blocks from my house and it is now a habit to turn off the fast idle just before I enter it.

 

As for the word "normal" I'd say this isn't normal. It is expected if you idle your bike without cooling but that is not a normal thing to do. It is against all advice including your owner's manual so it is "abnormal". So if you do something abnormal, you should expect and abnormal result so I'd say that red hot headers, although expected when your bike is abused in this manner, are abnormal.

 

Cheers,

Jerry

[RFW]

I was told by my mech that running at fast idle causes the normal system to be bypassed and the fast idle lever to pump excess fuel into the heads causing very rapid heat up.

His admonition:

NEVER run the bike on fast idle for more than the time it takes to start and maintain a smooth idle at 1000 rpm.

Basically that would mean about 30 seconds here in the north land at 5 C. my experience at least.

BTW shutting down the bike right away was probably not a great thing to do as the oil in the cylinders would be so thin there would be little lubricity left. The best thing would to be kill the fast idle, get on the bike and slowly ride around getting the temp down slowly.

His advice is right, but he hasn't a clue about why!

 

The fast idle lever doesn't pump anything "into the heads"!

 

The problem is simply that the bike's timing is intentionally retarted at idle for emissions reasons, creating a lot of heat in the exhaust. Increasing the idle speed simply increases the heat!

 

Bob.

[GordonB]

One more point! If your bike heats up like that, RIDE IT to cool it down, don't just shut it off. If for some rason you can't ride it (your helmets in the wash), put a house fan in front to cool it down.