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08R1200GS Lurching in 5th Gear

sand0628

New member
On 180 mile round trip ride today noticed that while passing a car in 5th gear, the motorcycle began to lurch like it was out of fuel then the problem went away. Arrived at Holt BMW to get a new set of tires. Marty the mechanic noticed the same thing on a test drive but only in 5th gear. On the way home I tested the GS several times in 5th gear and each time when I applied throttle it bucked, lurched and acted like it did not have fuel. I tested it in all gears and it runs and accelerates normally so the problem appears to only exist in 5th gear. Has anyone heard of a problem like this, if so what was the fix.
Thanks,
 
I suspect, unfortunately, that the problem is internal to the transmission: either a bent or badly worn shift fork or worn gear dogs. I think it is jumping out of gear and then back in.

Look for any sign of metal particles or a metallic sheen in the gear oil drained fromthe transmission.

And, what pray tell did Marty the mechanic tell you he thought it was?
 
Thank you for all of the suggestions. I did drain the transmission gear oil (75/90 synthetic) and it looked new, which would be expected as I had a major service done late last summer at about 35,000 miles all fluids were changed. I did not find metal pieces or suspended metal particles or anything else in the oil. I have right at 41,000 on the motorcycle now, I bought the 2008 new in April 2009. The lowest speed that I enter 5th gear is around 50 mph. I tried several things during my riding test and found that the bucking and lurching only occurred when I opened the throttle as one would when passing or building speed when entering a freeway. When I eased the throttle letting speed build very slowly over what felt like 1.5 to 2 minutes to go from 50 to 65 mph I did not experience the lurching and bucking; I also did not experience it when down shifting so long as I did not get on the throttle. I tested the acceleration in all gears and the only gear that has a problem is 5th gear but it is an ugly feeling problem!

It has been difficult to find anyone who has experienced the issues I am having and I do appreciate the comments, suggestions and questions. The folks at Holt BMW are trying to help me with the problem as well and I am taking it up to the shop on Tuesday, my next day off. I presently live in Charleston, WV and there are no BMW dealers in the state; Holt in Athens, OH is the closest and they are good people. I will post what I find and with luck it will help someone else.
 
Poor spark be it coil or plug could cause the bike to break down on hard acceleration. Bucking would be the result of one cylinder kicking in and out.

David
 
Your symptoms sound like the bike is running lean. "They all do that." I've heard that some use a Boosterplug or similar to trick the bike into a richer mixture during acceleration. If you search for Boosterplug, you'll likely find folks with symptoms like yours (our 09R1200RT suffers in that situation, too). Cheers!
 
I fixed this problem on my 2008 RT by replacing the spark plugs that had broken (cracked) insulators.

I replaced all 4 of course but the broken ones were the mains (horizontal plugs). I suspect poor factory installation technique, i.e. coils hammered on.
 
Since it was scheduled for service on the 14th, I wonder what the dealer found. It would also be interesting to hook up a GS-911 and check the readings from the gear position sensor.
 
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