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Discussion Starter #1
I have a 2005 LT with less than 10K miles on it. When the bike is warmed up, I can hear pinging (preignition) when I give moderate throttle. I always use 93 octane gas and have even tried about 1000 miles with octane boost added to the gas but it did not seem to help. The BMW diagnostic computer said no fault found but I had heard that borderline flakey O2 sensors could cause ping. I replaced the O2 Sensor on speculation but it did not help either...the exhaust soot has lessened significantly though.
Any other possible suggestions?
 

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At what RPM are you giving it moderate throttle. If your driving it in low RPMs lugging the engine it can ping.
 

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Discussion Starter #3
Even at 4K rpm though 6k rpm, the ping is there. It has been a few months since I have had it out on the road so I don't recall anymore how far around the dial it was present.
 

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I would recommend taking the bike into the dealer. Based on what you've done so far my guess this isn't something you're going to diagnose online or in your garage. Work with your dealer to try and get BMW to goodwill whatever fix they come up with, the bike is low mileage and not that far out of warranty.
 

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I just purchased a new 2009 LT last Friday. I also own a Harley... an 03 Heritage Softail. I say that because I want to qualify the following statement and to give it some context.

Whenever I engage the LT in first gear, going from a dead stop, I find myself having to rev up the RPMs and remain in half-clutched position for quite a while longer than I would have expected in order to get the bike moving off the line. The LT seems to produce engine knock and seems to lull and lag if I do not do this. There is a narrow envelope of revving the engine and applying just a certain amount of clutch pressure to avoid this knocking while in first gear.

By comparison, the Harley is very forgiving. I can begin to release the clutch in very low RPM and if I notice the engine is lulling and sputtering, I can very quickly roll the throttle to correct the situation and get the bike moving. It is very forgiving and can be put in motion withouth paying a whole lot of attention to the amount of roll on the throttle.

I know that coming from a Harley, the entire interaction with the drive train is completely different and it may just be a case of me having to get adjusted to the new feel of the LT. Once I get up in RPMs and out of first gear, I don't "sense" anything unusual. If I roll the throttle in 4th or 5th between 3 and 4k RPM, the bike responds aggressively. But from a dead stop, this bike requires an inordinate amount of RPM to get it rolling, and it doesn't seem to have much oomph when starting out.

I'd just like to get some opinions from other LT riders. Does this sound like typical behavior for an LT? Do you find yourself having to rev up the engine to avoid what otherwise sounds like regular good old- fashioned engine knock? I know it's a big heavy bike, but it seems to require a good deal of precision on the throttle and clutch to get the bike moving without killing the engine.

Anyway, I'd really appreciate any feedback. I love the bike overall. It's a very sweet ride. It's smooth and quiet and it is the very antithesis of my Harley. It's also much kinder on my backside and doesn't rattle my teeth! Finally, next week I'll be returning to the dealer for their free 600 mile checkup and I'll mention this with the mechanics there and see what they have to say.

Cheers
 

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Just learn the 'new way'. the LT isn't a torque monster like the Big Twin motors are. You do need more RPMs to get started, but the power is smooth all the way to redline. You're also dealing with a single plate dry clutch rather than an oil bath wet clutch. My experience is that the dry clutch requires a little more finesse, as you are seeing.

I have two V-Rods in the stable along with the LT, so I'm a little more used to RPM than you are - but once you've gotton the hang of it, it'll be second nature.
 

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Also the fact that the LT has a very tall first gear does not help. Hence it is not the fastest thing off the line, and it takes RPMs to make it move.
 

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I have a 99 with the air inlet temp sensor un plugged and the only time it has knocked was in stop and go traffic with the fans running , bike fully loaded and 85F OAT . It would knock a couple of times when lugging away from a stop and then as the rpms come up it would quit .
If your bike is knocking at mid to upper rpms I would look for an vacuum leak that is too large for the MoTronic to correct with more fuel , look at the plugs and maybe see if you can look in the spark plug hole at the top of the piston . If you have a lean ping /knock your plugs will look like they have been sandblasted and the piston will have a clean satin spot under the spark plug . Get it fixed as running a motor with a continuous knock will trash it .

Bob G
 
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