Join Date: Apr 2002
Location: Lexington, KY, USA
Wasn't the O2 sensor.
I have not ridden the LT the past few weeks because it just wasn't running right. It would bog down and stumble at lights, ran like it had a dead cyclinder, gas mileage had dropped to low 30's on a good day and it just wasnt smooth!
I scoured the LT site and it sounded like a dead O2 sensor, two weekends ago, I pulled off the rider and passenger pegs, the battery cover, the left skin and installed a new sensor. But alas, this was not the answer to the problem, still ran like my old 550 triple.
I happened to be at the local BMW shop shortly after replacing the sensor and the manager saw me, came over to ask how the bike had been running since they had replaced the output shaft seal on the tranny, installed the new clutch and replaced some of the rubber boots on the fuel injection system. I shared with him that it had run like a top until about 5 weeks ago when it started stumbling, stalling and just not running well. He told me to drop by with it and they would hook it up to the ole computer and see what they could see.
Opportunity allowed me to do just that last Tuesday. Took it in and they were kind enough to hook the bike up and found that the O2 sensor appeared to be searching all over the place. The O2 tracing looked like a sketch of the rocky mountains. Suggested a possible vacumn leak somewhere in the system.
I had a few hours today, so I stripped ole red down to her skivvies. Pulled the skin and started her up to see if I could hear any unusual hissing or sucking of air. Nothing but the irregular hearbeat I have grown accustomed to hearing. Pulled the tank back and checked to see if perhaps a critter had crawled into the air snorkle and died, nope, all was well there. All the lines to and from the tank were in good shape, no kinks, no holes. The lines coming off of the side of the injector ports were all clear and connected. As I sat on the ground next to the bike pondering the fate of what had become my mistress over the years, I decided to do some basic connection checking.
I pulled the panel off that covers the plugs and checked to be certain all the plug wires were snug. All seemed to be in order. I checked the injector ports to be certain they were all snug and that none of the replaced rubber coller/boots had been crimped or folded over when they were installed. Nope, all was in order. Grabbed the needle nose pliers and started checked the connections. Injector plug #1, snug, Injector plug #2, snug, Injector plub #3, fell off when I touched it with the pliers, #4 snug as a bug. Hmmm...
I released the spring latch mechanism, reseated the injector plug, clipped the latch back into place and fired old red up. Hmmm, sounded much better.
Turned her off and pulled plug #3. Wet as a dog from a lake. Cleaned it up, dried it off and reinstalled it. Checked all the connections once again and hit the start button. Little better. Unplugged the battery and went about putting the parts back on.
Reskinned her (anyone else have issues getting the stingray screwed back into place?) put the tools away, connected the battery and took her for a quick spin around the block. What a difference. She had her old personality back. No stumbling from a stop. Smooth as glass once under way.
Lesson learned. We had put close to 3000 miles on the LT in July while on vacation shortly after getting the bike back from the shop. It had performed beautifully during that trip. I evidently hit a large enough hole one evening returning to Olympia to finish dislodging the injector connector which had been incorrectly installed after the injection assembly repairs. ONe good thing is the disassembly allowed me to discover a very early oil leak under the bike. Too early to tell if it is an oil pan gasket leak or a rear main seal. That is an adventure for another day!