warm engine @ low RPM - runs like CRAP! - K-Bikes.com - Excellence in Motion
 
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old Jun 10th, 2010, 7:07 pm Thread Starter
Noob
 
Peterh's Avatar
 
Join Date: May 2007
Location: Ann Arbor, MI, USA
Posts: 28
warm engine @ low RPM - runs like CRAP!

Thanks for letting me vent....

I have a 2005 K12S w/ 27,000 miles on the clock. This spring, the engine developed the following symptoms: when fully warmed up (warm enough for the cooling fan to run) it runs on only 3 cylinders at RPM below ~3500. Above this RPM, all is good. When the engine is cold, it runs smoothly at low RPM. The bad news is that the techs couldn't find anything wrong and suggested that it seemed normal to them. The good news is that they charged me $0.00 for running the diagnostics and checking obvious potential explanations, e.g,. loose plug wires, etc.

Can anyone suggest what is going on? I know that rough idling is not uncommon for some K12S bikes, but temp-related changes in low RPM performance is new to me.

Thanks in advance,

Peterh

2005 K1200S (Awsome!)
2002 R1150RT (nearly perfect)
long impatient pause....
1976 Honda CB750K
1972 Yamaha 350 R5-B
1970 Honda CL 350 Scrambler
Peterh is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old Jun 10th, 2010, 9:10 pm
Veteran
 
Join Date: Jun 2006
Location: , ,
Posts: 2,680
Coil breaking down from heat?


Mack
GMack is offline  
post #3 of 7 (permalink) Old Jun 10th, 2010, 10:03 pm
JCW
contributor
 
JCW's Avatar
 
Join Date: Aug 2006
Location: Chicago, IL, USA
Posts: 4,827
Quote:
Originally Posted by Peterh
The good news is that they charged me $0.00 for running the diagnostics and checking obvious potential explanations, e.g,. loose plug wires, etc.

While your situation is not funny, I find the above statement is since the bike has no plug wires.


On a 2005 bike I would think bad coil as well. Unfortunately, a coil can measure OK when off the bike but not work well when actually in service. Also, they are expensive to replace just to check.

I would make sure it's only running on 3 cylinders. An easy way to do this is to put you hand on the exhaust pipes. If you don't leave pieces of melted flesh on one, it's probably not firing all the time.

But, it could be anything from the plugs, coils, crankshaft sensor, fuel pressure regulator, fuel pressure sensor, fuel injectors, fuel filter, etc.

This is where a true mechanic comes in handy. Not one that plugs it into a computer and says EVERYTHING's FINE.

'06 K1200R- in pieces
'73 Honda CB500F- slow but fun.
'77 Yamaha XS 750 triple- kinda
JCW is offline  
Sponsored Links
Advertisement
 
post #4 of 7 (permalink) Old Jun 11th, 2010, 11:28 am
Addict
 
cjack's Avatar
 
Join Date: Aug 2003
Location: Urbana, IL, USA
Posts: 555
Quote:
Originally Posted by JCW
While your situation is not funny, I find the above statement is since the bike has no plug wires.


On a 2005 bike I would think bad coil as well. Unfortunately, a coil can measure OK when off the bike but not work well when actually in service. Also, they are expensive to replace just to check.

I would make sure it's only running on 3 cylinders. An easy way to do this is to put you hand on the exhaust pipes. If you don't leave pieces of melted flesh on one, it's probably not firing all the time

snip
Well there are wires to the coils...
You might buy one of those IR temperature reading devices...Harbor Freight has them for less than 50 bucks and save the skin on your hands. They are really great for checking exh pipes.

Jack Hawley
MOA #224
cjack is offline  
post #5 of 7 (permalink) Old Jun 11th, 2010, 3:58 pm
Noob
 
Join Date: Aug 2009
Location: Cincinnati, OH, USA
Posts: 4
Intakes

I had a similar issue on my '05 K1200S: ran very rough at idle when engine was hot. I went through many of the same diagnostics, but in the end a simple cleaning of my intake air filters fixed the problem. They were caked with leaves, rocks, half a dead bird, etc (why BMW doesn't put screens over those gargantuan intake ports is beyond my comprehension).

I can only assume that for some reason, on my bike, the air pressure required at intake is greater when the engine is hot, which is why my clogged filters would manifest the problem only when engine was hot. I also had a thought that it might be related to the left intake being more clogged than the right one, and perhaps the bike favors the left intake at idle? All I do know is that the process of cleaning them out (whether it was intake obstruction or something else I accidentally fixed while pulling it all apart), fixed my problem. Good luck.

--
WarrenT
'05 K1200S

--
WarrenT
'05 K1200S
timmerwd is offline  
post #6 of 7 (permalink) Old Jun 16th, 2010, 4:45 pm Thread Starter
Noob
 
Peterh's Avatar
 
Join Date: May 2007
Location: Ann Arbor, MI, USA
Posts: 28
simple fix

At the end of the day, it was a simple fix... Fifty miles w/ STP fuel system cleaner in the tank, and most of the symptoms went away.

cheers,

2005 K1200S (Awsome!)
2002 R1150RT (nearly perfect)
long impatient pause....
1976 Honda CB750K
1972 Yamaha 350 R5-B
1970 Honda CL 350 Scrambler
Peterh is offline  
post #7 of 7 (permalink) Old Jun 17th, 2010, 10:08 am
Senior Member
 
Join Date: May 2009
Location: Denville, NJ, USA
Posts: 128
If you can find it, BMW recommended Techron Concentrate (not the dilluted one) for the ailing 1300s that were stalling. Maybe the same stuff, but why not! Found it at Pep Boys and Advanced Auto Parts. Most auto parts places should have it.

Now: K1300S Lava Orange
Then: R1100s, CBR929RR, YZF 600, Triumph Sprint ST, VFR750, K75S, GS1150E, GS550E, GS750E, KZ550, GT 380
clem21 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the K-Bikes.com - Excellence in Motion forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
K1300GT intermittent engine stalling? Vega K12/1300GT (Next Gen) 33 Jul 6th, 2018 5:42 pm
Absolutely the most detailed description of the K1200S I've come across... sinc K12/1300S 20 Jul 19th, 2014 9:04 am
A ride tale Arr2Kay Bike Talk 8 Dec 1st, 2010 2:42 am
Internation Motorcycle Show jewilson K12/1300S 5 Nov 14th, 2009 9:35 pm
Hard to start when engine warm? BrianT K12/1300GT (Next Gen) 9 Mar 29th, 2007 8:07 pm

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome