270 Posted September 24, 2009 Share Posted September 24, 2009 Hey gang! I'm about to replace the stick coils for the THIRD time on my '04. That's four sets (I've been replacing both on a failure) and it's getting a little expensive. I've got an observation though when they have failed; all three times have been during long trips in extremely wet conditions. I can't see how water can get into the valve covers or contact the coils, but maybe the continual spray on the hot covers has something to do with it. If anyone has any other theories, I'm open to hearing about them. I just made a trip from Dallas to LA and back and it was not a pleasant experience with crappy coils! Thanks for any thoughts. Link to comment
Dallas Posted September 24, 2009 Share Posted September 24, 2009 I've only had one failure so far on my '04 RT. It was also after riding in the rain. Link to comment
AndyS Posted September 24, 2009 Share Posted September 24, 2009 I've got an observation though when they have failed; all three times have been during long trips in extremely wet conditions. I can't see how water can get into the valve covers or contact the coils, but maybe the continual spray on the hot covers has something to do with it. I have had one fail. I was touring france in very warm weather when I noticed it, but to be perfectly frank, it takes a while to realise something is wrong unless you are pulling heavy load. The secondary plug seemed to mask the problem so well. Andy Link to comment
jblaze5779 Posted September 24, 2009 Share Posted September 24, 2009 Just replaced both of mine on an 04. Link to comment
peterbulgar Posted September 24, 2009 Share Posted September 24, 2009 Very interesting. One of mine failed on a trip the summer before last - it took two dealers to diagnose what was wrong. The bike had 60k miles on it, so I just figured that 60k miles is the service life of a stick coil. However, I also first noticed the stumbling under hard acceleration and uneven idling after riding in heavy rain. You may be on to something here, although I don't know why rain would permanently affect a coil. Peter '73 R75/5, '04 R1150RA Link to comment
JamesW Posted September 24, 2009 Share Posted September 24, 2009 Got two stick coils on order as we speak. Have been searching for a less expensive alternative or after market coil without much success. Link to comment
270 Posted September 24, 2009 Author Share Posted September 24, 2009 Got two stick coils on order as we speak. Have been searching for a less expensive alternative or after market coil without much success. Yea, same here...not sure if there is another alternative. I wish I knew what was causing the failures. It's beginning to be annoying! For what it's worth, the bike was fine until about 40K...The last 2 and now 3rd are in the last 20K. Link to comment
JamesW Posted September 24, 2009 Share Posted September 24, 2009 New coils arrived about one hour ago and all works well and hopefully will continue to do so. Should have bought them from Chicago BMW as I would have saved about 80 bucks. According to the parts guy at ChiBMW the new coils with part # 12137715853 have been trouble free. My new coils have this #. There is no longer any doubt that I lost the first coil some time ago but didn't see the light until the second coil failed. At least I have learned how to determine if poor starting and erratic idle is caused by a coil failure. Probably not a bad idea to carry a spare coil and buy it from you know who. I can't remember when my machine started this good cold and idled this well. Link to comment
270 Posted September 25, 2009 Author Share Posted September 25, 2009 New coils arrived about one hour ago and all works well and hopefully will continue to do so. Should have bought them from Chicago BMW as I would have saved about 80 bucks. According to the parts guy at ChiBMW the new coils with part # 12137715853 have been trouble free. My new coils have this #. There is no longer any doubt that I lost the first coil some time ago but didn't see the light until the second coil failed. At least I have learned how to determine if poor starting and erratic idle is caused by a coil failure. Probably not a bad idea to carry a spare coil and buy it from you know who. I can't remember when my machine started this good cold and idled this well. James, thanks for that P/N...I haven't seen that one, but I'm game for whatever else works. My RT has really been trouble free despite my pucker factor on everything else...except this! This is beginning to be a bit much, but I'm ready for the fix... Link to comment
JamesW Posted September 25, 2009 Share Posted September 25, 2009 I just can't seem to leave this alone. I was out looking at my Ford as it uses HV coils one for each plug and I notice that there are only two pins on the connector that goes to each one not three like to the BMW coils. On the BMW coils one pin has +12 volts, one pin is connected to ground, and one pin appears to be the switched ground from the Motronic. I wonder what the pin is for that is connected to ground and could the problem with the stick coil not be caused by a low impedance shunt to this ground which would affect the strength or voltage available to fire the plug. When I studied transformer theory I learned that if a transformer develops a shorted winding then that be all she wrote for the transformer yet these stick coils seem to function at a much lower output voltage as proven by their ability to produce enough energy to produce a spark across a plug gap when the gap is greatly reduced. Anyway, I think the third pin which is connected to ground might be there for the purpose of shielding to minimize noise which could adversely affect radio reception. So, out comes the needle nose pliers and I snap this third pin off the malfunctioned stick coils and I re-install them and fire the beast up. I can't believe it! Bike runs great! Go figure..... The pin in question is the middle one of the three. Link to comment
270 Posted September 25, 2009 Author Share Posted September 25, 2009 You're freakin' kidding me?!? I do know these are "radio interference" coils, or produced for the express purpose of eliminating radio noise. Could this be??? Pin in the middle? I'm heading now...despite the 4 glasses of red wine... Link to comment
270 Posted September 25, 2009 Author Share Posted September 25, 2009 OK...back in now...FWIW...it does seem to idle BETTER, but not great. I rode around the block, got a little heat in it, and it ran better still. Honestly, it feels like it's got one bad stick coil now... You might be on to something here. I'll try highway speeds tomorrow...with gear...and no alchohol in the system. Mine that is... Link to comment
JamesW Posted September 25, 2009 Share Posted September 25, 2009 Wellll, on one of my coils I read about 10 MegOhms from spark plug connector pin to the center (ground) pin. This probably should not be. Like you I have come to the conclusion that this shunt to pin 3 which is grounded seems to be the problem with one of my coils not sure about the other one. Needless to say I am not going to throw either in the old circular file just yet. Link to comment
JamesW Posted September 25, 2009 Share Posted September 25, 2009 Checked OEM Parts to see what the R1200 bikes use for ignition coils and found that they use not two but FOUR stick coils. Yup, even secondary plugs are using them, GREAT! Now, since I don't own a HEX head nor do I plan to own one I don't spend much time reading HEX head forums so I wonder if there have been posts regarding strange rough idle, hesitating under load, surging, etc. Link to comment
270 Posted September 25, 2009 Author Share Posted September 25, 2009 I need to check the resistance, but certainly it runs "better" than it did. Is it possible that there's more than one failure mode? Same P/N for the hexhead's stick coil btw... Link to comment
JamesW Posted September 25, 2009 Share Posted September 25, 2009 I suppose there is more than one way for the coil to fail, no doubt. I measured the high resistance to the middle pin from the plug connector on only one coil but not the other. Also could be that the coil I couldn't read resistance on requires a higher potential than that found on my multimeter to break down. I have been thinking that maybe it wouldn't be such a bad idea to snap the center pin off the new coils before installing them. Might prevent a future problem? When arc over occurs in high voltage applications a carbon trail often results which can insure continued faulty performance of the component. It does bother me the idea of snapping pins off a device(s) I just paid 278 smacks for if you know what I mean. However, I'm gonna do it! Link to comment
Deadboy Posted September 25, 2009 Share Posted September 25, 2009 OK, I'll bite....how do I know if my stick coil is bad? I have just under 60K on my 04RT and it does seem to idle a bit roughly on occasion.... Link to comment
JamesW Posted September 25, 2009 Share Posted September 25, 2009 The deed is done. Instead of breaking the middle pin off the stick coil I just removed the back shell from the female coil connector and snipped the brown wire. In fact I shortened up the brown wires by about 1/8" just to make sure no arc over. IMO I just eliminated one big potential problem. Bike runs fine and I'm going to bed. Link to comment
JamesW Posted September 25, 2009 Share Posted September 25, 2009 Deadboy, remove the plug wires from both secondary plugs and ground them to prevent potential damage to the Motronic. If the bike starts and runs then chances are your stick coils are good. Then just for fun unplug the connectors to the stick coils, re-connect the secondary plugs and start bike again. If bikes runs on just the secondary plugs then secondary coils and cables are good. Link to comment
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