‘06 K12s - Driveline clunk /thunk in 3rd gear on the throttle..

[Snicko]

I did a search through the forums and a poke around with google and didn’t turn anything up like this so I thought I’d post here. 

I have an ’06 K1200S with just shy of 45k mi on it. Bought it 2 months ago from the second owner who bought it in 08 with 8k miles on it. I’ve put about .. 1500 miles on it so far. 

The prev owner had some maintenance receipts and I was able to fill in some gaps with calls to the local BMW dealers. I think teh last time a dealer saw it was with 32k miles on it for an oil change and service (valves, IIRC). I have Maintenance showed nothing nothing remarkable about them - regular services & oil changes.

I threw a front tire on it after buying it as it was pretty ragged. The rear was OK (squared off but tons of tread left) so I left it alone (plus nobody had a Pilot 6 in the right size). 

Under judicious throttle I’d occasionally hear and feel a clunk / thunk in the rear and the bike would jump a bit. I felt it a couple of times about 3 weeks ago and kinda wondered if I was just spinning the rear cause it was so old so threw a new Pilot 6 on it. 

The clunk is still there unfortunately. I did a long loop today (for those of you familiar with the Bay Area - 84 to Hwy 1 to Bonny Doon to Big Basin to Hwy 9 to 35 and back home. 

As the ride went on in the twisties the clunk was a bit more reproducible. It happens in 3rd gear. I’ve tried in 2nd and 4th with no luck, but that could be that I’m running out of room before I get sufficient power out of the motor to make it happen…

It doesn’t appear to matter if the bike is leaned over or straight.

As the day went on the clunk / thunk / hiccup felt like it was happening at lighter throttle positions. At one point it happened just as I was starting to feather the the throttle for corner entry. 

So, my first though is the clutch. The maintenance records have nothing for the clutch so I assume its original. The clutch bite is at the very end of the lever throw and its very veyr short. It makes a bit of a screeching noise at the end of the the lever’s throw. Could the clutch just be slipping? 

It only happens in 3rd gear which is a bit odd and doesn’t make the clutch theory make 100% sense. The transmission shifts fine (well, as fine as this generation transmission does - its a bit clunky). Could the transmission be kicking out of 3rd gear momentarily? That seems a bit odd. It goes in and out of 3rd just fine. 

The only other thing I can think of is in the shaft drive somewhere but like the clutch - its only in 3rd gear…

Soooo.. anyone have ideas?

Thanks! 

[Arjun]

This happened with me but on my first bike a 2014 KTM 390duke. Turned out that one of gears was stripped because of some metallic piece grinding on it. No clue how that happened  but I pretty much used to mistreat it a lot ( I was 14 and India where the roads are non-existent), Nothing like this on my 32 days old 01 k12rs did around 3k+ miles on it till now. 

[dirtrider]

 

Quote

I did a search through the forums and a poke around with google and didn’t turn anything up like this so I thought I’d post here. 

I have an ’06 K1200S with just shy of 45k mi on it. Bought it 2 months ago from the second owner who bought it in 08 with 8k miles on it. I’ve put about .. 1500 miles on it so far. 

The prev owner had some maintenance receipts and I was able to fill in some gaps with calls to the local BMW dealers. I think teh last time a dealer saw it was with 32k miles on it for an oil change and service (valves, IIRC). I have Maintenance showed nothing nothing remarkable about them - regular services & oil changes.

I threw a front tire on it after buying it as it was pretty ragged. The rear was OK (squared off but tons of tread left) so I left it alone (plus nobody had a Pilot 6 in the right size). 

Under judicious throttle I’d occasionally hear and feel a clunk / thunk in the rear and the bike would jump a bit. I felt it a couple of times about 3 weeks ago and kinda wondered if I was just spinning the rear cause it was so old so threw a new Pilot 6 on it. 

The clunk is still there unfortunately. I did a long loop today (for those of you familiar with the Bay Area - 84 to Hwy 1 to Bonny Doon to Big Basin to Hwy 9 to 35 and back home. 

As the ride went on in the twisties the clunk was a bit more reproducible. It happens in 3rd gear. I’ve tried in 2nd and 4th with no luck, but that could be that I’m running out of room before I get sufficient power out of the motor to make it happen…

It doesn’t appear to matter if the bike is leaned over or straight.

As the day went on the clunk / thunk / hiccup felt like it was happening at lighter throttle positions. At one point it happened just as I was starting to feather the the throttle for corner entry. 

So, my first though is the clutch. The maintenance records have nothing for the clutch so I assume its original. The clutch bite is at the very end of the lever throw and its very veyr short. It makes a bit of a screeching noise at the end of the the lever’s throw. Could the clutch just be slipping? 

It only happens in 3rd gear which is a bit odd and doesn’t make the clutch theory make 100% sense. The transmission shifts fine (well, as fine as this generation transmission does - its a bit clunky). Could the transmission be kicking out of 3rd gear momentarily? That seems a bit odd. It goes in and out of 3rd just fine. 

The only other thing I can think of is in the shaft drive somewhere but like the clutch - its only in 3rd gear…

Soooo.. anyone have ideas?

Morning Snicko

 

Difficult to tell you anything for sure without riding that motorcycle but it sure sounds like it is momentarily jumping out then back into 3rd gear.  

 

On the K1200S it is usually 2nd gear (I have seen a few of those) but I have also heard of a few 3rd gear problems (usually a bent or worn shift fork) but if ridden long enough with a bent or worn shift fork then it wears (rounds) the shift dogs. Then even a new shift fork won't stop the gear jumping out & back into engagement. 

 

About all you can do (if it is actually jumping out then back into 3rd gear) is to verify the shift lever is able to shift it FULLY into 3rd gear, that the shift linkage/lever is tight on the transmission end.   

 

Check your personal messages on this site as I sent you some additional information.

[gary45]

Driveshaft possibly, the driveshaft itself made out of two metal sections joined in the middle, the lower section goes into the upper section joined with rubber and it can slip.

 

You will find more info on BMWLT forum 

[dirtrider]

47 minutes ago, gary45 said:

Driveshaft possibly, the driveshaft itself made out of two metal sections joined in the middle, the lower section goes into the upper section joined with rubber and it can slip.

 

You will find more info on BMWLT forum 

Morning  gary45

 

The drive shaft would make sense if it happened in all gears, or the lower 3 gears, or  more the just 3rd gear. But ONLY happening in one gear pretty well rules the drive shaft out. 

 

That & the fact that Snicko says__   "As the day went on the clunk / thunk / hiccup felt like it was happening at lighter throttle positions. At one point it happened just as I was starting to feather the the throttle for corner entry"__   that more points to a gear engagement issue as typically the drive shaft slips more under higher engine loads not at reduced reduced engine loads, or under throttle feathering conditions. 

[Beech]

There are several K1200S bikes being parted out on the K bike forum. The transmission replacement is possible by someone handy but it is involved and technical. I suspect previous owner knew about this. Sorry.

[Lowndes]

K bike forum:

 

https://www.k-bikes.com/

[KBMWGT]

Suggest dropping the rear end and take out the shaft.....lube it while your there. I bet you find a u-joint breaking or broke.

 

Where are you located?

[dirtrider]

7 hours ago, KBMWGT said:

Suggest dropping the rear end and take out the shaft.....lube it while your there. I bet you find a u-joint breaking or broke.

 

Where are you located?

Morning  KBMWGT

 

But why then ONLY 3rd gear, & not 2nd gear (higher torque) or 4th gear (less torque), just 3rd gear? Seems to me the very same "U" joints are used in all the gears.  

 

 

[KBMWGT]

Oh I'm not definitive in my suggestion. Just a check off a list item that you can actually do at home. My prior K1100 had the clunk and it was the u-joint broken and jammed together to actually still spin the shaft.

 

[Beech]

So what did you find. As mentioned I suspect slipping out of gear and re engaging. Common with worn K12 trannys. The K13 bikes have undercut shift engagement dogs and do not have this problem.