Bad gas?

[bushmanstan]

2007 RT with 10,000 miles had run perfect up until a few weeks ago when I dropped it on it's left side. With help from this board I discovered the stick coil had partially dislodged on the left jug. The bike seemed to be back to it's old self.

 

This past weekend I filled up with fuel and left on an overnight trip to the Buffalo River. A round trip of about 240 miles. This had been an easy pace 2-up ride with no full throttle 2 lane ride. About 45 miles from home I hit the interstate on ramp and when I twisted the throttle to full the bike practically fell on it's face. Return to mid-throttle setting and it ran fine. The same results for all upper gears.

 

I'd say there are a couple of gallons or so of fuel left in the tank. I have always thought that water in the fuel would make itself evident soon after a fill up and not wait until the tank was 2/3rds dry.

 

What are your thoughts? If it is fuel how do you go about draining the tank?

[Mr_Ed]

Could be bad gas but then again it could be due to bad spark. You can try treating with some stabil or seafoam but, if you have ready and easy access to a dealer it might be worth you while to have them check for any fault codes.

[Firefight911]

If you had a tipover that dislodged the coil, you may have a cracked spark plug.

 

I doubt it is gas related. You would know it as the same gas is being used at idle and at speed and at full song.

[T__]

bushmanstan, unfortunately your problem could be one or more of a few things..

 

It sort of sounds like a fuel supply problem (not really a water issue) but could still be a problem with the coil or a spark plug issue..

 

With the bike falling over you could have dislodged sometime inside the fuel tank,, or you might have cracked a spark plug,, or you might have done some other damage to that coil..

 

I guess I would start with a new upper spark plug on the damaged side,, then check the other 3 for fouling..

If it still acts up you will probably have to dig a little deeper into possibly investigating the coil or doing a fuel pressure/flow test..

 

 

Twisty

 

 

 

 

[bushmanstan]

Ed, Phil & Twisty,

 

Thanks for the feedback. It looks like my bike will be going to the dealer for this one. Good news is that we have a top notch dealer here in NW Arkansas.

 

Stan

[Lawman]

http://www.bmwmoa.org/forum/showthread.php?t=41066

[Don_Eilenberger]

The symptom you give is exactly the symptoms of an ignition failure Once - A LONG LONG TIME AGO - I chased exactly the same symptom in a Volvo 122S that I owned. After an entire weekend of diagnostics while on vacation in Cape Cod (SWMBO was NOT happy,) finally went to a small VW garage. He listened to me, grabbed 4 new plugs, put them in and said "Go try it.." he was right. Ran perfectly.

 

Ignition components can break down under load. In the case of the Volvo - the plugs were worn out and failing to fire under high compression loads.

 

I'd start with plugs. If the plugs don't cure it - then I would try a new ignition coil on the one that got dislodged. (I can say that pretty easily since I have a complete spare set - but you might want to find a friend with a hexhead who would be willing to let you try a short swap to see if the symptom goes away.. they are costly buggers [especially compared to the about identical ones used on BMW cars which are 1/4 the price..])

 

EDIT: BTW - a coil failure stores no error codes on the Hexhead ECU. Dumb, but there it is. A dealer will have to try substitution to sort it out. Might save some money DIY.

[Paul Mihalka]

"Good news is that we have a top notch dealer here in NW Arkansas."

 

Bentonville BMW

[bushmanstan]

Thanks for the additional feedback. I will start with the spark plugs. Can someone verify the socket size for the plugs; is it 16mm?

 

I previously removed the stick coil for inspection and saw nothing out of order but could not find the appropriate socket to remove my plugs.

 

[Highway41]

Thin wall 16mm. I JB welded one to a 6" extension.

Bill

[bushmanstan]

Bill,

 

Thanks for the info. Did you get a 16mm "spark plug" socket or just use a deep socket?

 

Stan

[BeemerLover]

Harbor Freight has one... ITEM 91705-0VGA or go to http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91705

[bushmanstan]

Gael,

 

Thanks for the info. I bought a 16mm deep socket at Lowe's and it did the trick. I did have to grind it down some to fit the bottom spark plug hole.

[BeemerLover]

Stan: GREAT! Don, can the BMW car ignition coils be adapted or modified to work?

 

 

[Don_Eilenberger]

Don, can the BMW car ignition coils be adapted or modified to work?

Unfortunately - no. The connector (which is molded in) is completely different, and even if you spliced in the connector from the car - the actual coil is longer (and fatter I believe.. have to look, I have some spares of each.) The car coils are actually not terribly reliable. BMW-NA issued an extended warranty on the coils for several of my Bimmers, extending the warranty on the coil to 8 year and unlimited mileage. I've had enough fail that I carry a spare in each of my Bimmers (3 of them..)

[BeemerLover]

Rats!

 

 

[chaparral]

Check the coil insert by the plug. I had the same symptom only under acceleration after I changed plugs. Stupid I left the upper plug slide-on by the coil about 1/8" gap for a full seating. Somebody here reminded me to check the slide-on. That fixed it. Figgered a dual pluger wouldn't act that way but it does. Must be too much fuel for just 1 plug to ignite

[BeemerLover]

Just thought of something that I have done on classic cars where I suspected the spark plug wires were arcing to ground. Wait until it is really dark outside and spray a very very fine mist of water around the area where the wires are located. Then start the bike up and watch for arcing.

 

 

[bushmanstan]

FYI, installed 4 new plugs and the bike runs like new. The lower left plug was dark and kind of oily; possibly from my original left side drop a few weeks ago.

 

Thanks for all the helpful feedback.

 

Stan

[Don_Eilenberger]

Just thought of something that I have done on classic cars where I suspected the spark plug wires were arcing to ground. Wait until it is really dark outside and spray a very very fine mist of water around the area where the wires are located. Then start the bike up and watch for arcing.

Gael,

 

Great idea if the vehicle has ignition wires. The R1200 motor has none. Coil/on/plug would be kinda hard to spray a mist of water on and watch since both coils are encased to some extent (and there is no wire.)

[lvnvbiker]

There could be some fouling on the leads goingt to the stick coils, or one of them could be loose. The little wire leads that supply power to the coils have pretty fragile connectors on the ends, and the little retainer clip part is known to snap off quite easily. I would check those to make sure they are locked into possition and maybe put a bit of dielctric on them especialy around the sealing area. While not like a traditional sparkplug lead which is after the voltage is stepped up, these are relatively low voltage but they be fouled or even possibly shorting somewhere along thier length... Hell if the problem is only under load when the motor is "moving" more than normal it is possible that one could be grounding out. It's worth a look and really nothing to lose by inspecting them.

[Don_Eilenberger]

It's worth a look and really nothing to lose by inspecting them.

It's always worth a look - but spraying them with water is likely to do nothing for the diagnosis, and there won't be any sparking visible from a low voltage path.

[BeemerLover]

Don, you are right, that only works if the wire is downstream from the coil. I didn't remember that the coil is on the plug. Seems like an odd configuration but maybe it improves performance somehow.

 

 

 

 

[Firefight911]

Don, you are right, that only works if the wire is downstream from the coil. I didn't remember that the coil is on the plug. Seems like an odd configuration but maybe it improves performance somehow.

 

 

 

 

It is much better with a coil stick. It puts the high voltage as close as possible to the spark plug and, therefore, there is less voltage drop with distance and less interference from wire runs. It also improves timing, as it reduces time/distance. Today's systems run some pretty high voltages compared to the distributors and coil systems of the past.

[Don_Eilenberger]

It is much better with a coil stick. It puts the high voltage as close as possible to the spark plug and, therefore, there is less voltage drop with distance and less interference from wire runs. It also improves timing, as it reduces time/distance.

All true - but since electricity travels at the speed of light, it might be hard to measure the reduction in time/distance...

 

Today's systems run some pretty high voltages compared to the distributors and coil systems of the past.

Dunno what voltage the on-plug systems run. Electronic ignition systems with big honking coils did get up to around 40kV at one point (vs point's ignition which pretty much maxed out at 20kV.) The smaller coils required for coil on plug systems may end up outputting a reduced voltage since it's harder to insulate things when they become more compact. Have to see if there are any spec's available.

 

FWIW - coil failure is quite common on BMW cars. It seems less-so on our bikes.. but the coils on the bikes are a bit better ventilated than the totally enclosed ones on BMW cars.