What year is your K1200RS ?
Year is very important as the 2nd generation of K1200RS (having front nose facelift fairing AND lower pegs) came from factory with a very different Starter Relay. The 2nd gen are mainly 2001-2005 in Canada and 2002-2005 in USA. Earlier models had a regular (black colored) Starter Relay under fuel-tank - located in electical junction box.

This new so-called "smart Relay" is Blue and has electronic circuitry embedded into it so that the starter will not engage when battery voltage is roughly below 11.7 volts. In such condition it will not even make any click of any noise when you press starter button.

BMW has never published the official voltage value under which the newer Stater Relay will not engage, but various tests over the years have shown the theshold to be roughly 11.7 volts. IMPORTANT: this value needs to be measured at your battery terminal after igniton ON - wait 10 seconds - do NOT attempt to start - mesaure static voltage at battery. Because of the permanent headlights/rear-lights , dash and ECU all takes some power this value will be much lower that a static measurements with ignition OFF.

ALWAYS Double check your assumptions / tests with another good known VoltMeter.

FINALLY.... if you do have a 1st generation K1200RS (mainly 1997-2000 for Canada), then above might NOT apply.
HOWEVER, in parts catalog BMW has a so-called "retrofit kit" for the newer type Starter Relay to retrofit older 1st gen with this. So UNTIL you open the electrical relay box under fuel tank to check relay shape / color, you cannot be 100% sure what version you have. When a K1200RS was brought up to dealer for starter relay problems, the dealer would sometime recommend the owner to install the newer type on 1st generation.

See attached photos to identify older BLACK Relay and newer BLUE Starter Relay...

 

Hi Sailor, thanks, so mine is a 2002 K 1200 RS, USA model. I turned it on and measured static voltage after 10 seconds, 20 seconds, etc, 11.75 V each time, 2 meters. Sounds like that's pretty close to the lower starter relay engagement threshold based on your thread.

I also took/attached a picture of the starter relay, blue BMW tyco, part # 6135-7655540, same as yours. Terminals are a bit oxidised, but otherwise looks good.

So, sounds like a new battery?

 

Over 30 years maintaining my motorcycles and some others (friends), the average life of a battery has been 2 to 8 years depending on many variables. Of course the quality of the product / brand and type of usage (frequency) is key.

BUT BEFORE you spend any money on a new battery, I would try the following to confirm your battery is old / weak.
1) clean all Male contacts of the Starter relay and the joining large female connectors. Make sure each pin is making a good tight contact into female connectors. If you have a few spares Spade shaped connectors (in bulk) this will make testing each pins easier - sometimes a pin does not fit tightly or the joining female pin has moved out of its socket..

2) make sure both battery terminals are clean and tight. ALSO, make sure you do have 2 black wires attached to negatibe post of battery. On a stock k1200RS you should have 1 thick-large black wire AND a medium-thick black wire tied togeter on negative pole.

3) try the same start after a good battery charge. Watch out for some old / cheap charger that will trow too much amps (mainly car chargers) OR too much voltage during the charging process - it should not exceed 14.7 volts

4) if you have a good autoparts in yor area they may offer a service to "load test" the battery. In fact, you can buy your own load lester for about $US$ 50. Load testing gives a much better picture of state / age than only voltage testing can.

5) Any 12 volts car battery can be used (jumper wire method) to test a start with a good external battery. Do NOT try this if you are not familiar with proper battery jumping procedure - you could damage your ECU or even burn your whole wire harness.

CONCLUSION:
The goal here is to try one or several start with battery much above 11.7 volts (tested after ignition ON). Besides an old / weak battery (most probable cause) during last 15 years on 3 different K1200RS-LT forums we have seen 4 cases of defective blue stater relay as they get older. This is not common, but still a probability that will be easy to spot once you have a good battery.

IMPORTANT to REMOVE battery:
I have seen this mistake done so may times on forums, that it is worth repeating to avoid important damage:
When removing / disconnecting a battery:
A) ALWAYS start with Negative Post wire(s) - isolate this post wire(s) from touching battery
THEN
B) unbolt / undo the positive post wire(s)

Battery installation is reverse, so you attach Positive wire first.

 

Hi Sailor, I completed the 5 above steps. Starter relay connection good, terminals were good, old battery charged, but couldn't manage load (11.8 V after ignition on and wouldn't start), so tried good battery, it started readily so I bought a new battery, and it works fine now. BTW, new battery installed, battery volts with ignition off at 13 V, and with ignition on, 12.1 V. Thanks for the help Sailor. Also, guys, if you need to push start because of a similar battery issue, simply turn ignition on, wait for ABS pulse to finish, then hold start button on, turn key to off and back to on, should start right up for you, not sure why but worked well for me as an interim measure until I sorted this out, seems to by-pass the starter relay minimum voltage requirement, in a pinch.

 

Hi Sailor, I completed the 5 above steps. Starter relay connection good, terminals were good, old battery charged, but couldn't manage load (11.8 V after ignition on and wouldn't start), so tried good battery, it started readily so I bought a new battery, and it works fine now. BTW, new battery installed, battery volts with ignition off at 13 V, and with ignition on, 12.1 V. Thanks for the help Sailor

Also, guys, if you need to push start because of a similar battery issue, simply turn ignition on, wait for ABS pulse to finish, then hold start button on, turn key to off and back to on, should start right up for you, not sure why but worked well for me as an interim measure until I sorted this out, seems to by-pass the starter relay minimum voltage requirement, in a pinch.

Thank you for the feedback / news on this. Glad you got this fixed.

Out of all request about "no-start / no-crank" condition on most modern bikes having lots of electronics, I would say the Battery is the cause in more than 50% cases. Many make the mistake to tell forum they have tested battery just after a charge and they see a good value (like 12.6 to 13 volts) - this test is worth little as I have explained earlier unless you wait 10 to 30 sec AFTER ignition ON to make the reading.

With a weak battery, modern cars / motorcycle often behave differently than older vehicule where you would hear a faint click OR a starter trying to barely turn slowly.

I fact your last paragrah is quite instructing as I had never tested this sequence on a K1200RS/LT equipped with newer "smart" starter Relay. HOWEVER, given the issues / consequences of starting with a weak Battery on the older Relay type, I would suggest to AVOID trying your trick again. In such scenario, the Relay contact will often weld together and not release - the only way to stop Starter from overheating is to grab wrenches and unbolt battery - the ignition OFF will NOT do it in such case. You have been warned... ;-)

 

Thanks, good to know!

 

Sailor, I seem to be back where I started. I followed through on your five suggestions above, eventually leading to a new Yuasa battery installation (which was due). New batt in, got a few good starts, no problem. Then, next day, no joy on restarts.

So I used a good quality charger to top the new batt off overnight. Then reinstalled and checked battery, all readings with ignition on, post spool up, 12.1 V plus. Attempted start, a few worked then not.

Disconnecting head lights gives a bit more power, and seems to help with bike starting up no problem, but volts at start are then 12.5V plus, which is getting to be a pretty high battery power threshold. You mention in your Conclusion that once one has good power that issues with the blue starter relay (in my bikes case) while uncommon are easily spotted. How so? Do blue started relays fail in such a fashion?

 

Sailor, I seem to be back where I started. I followed through on your five suggestions above, eventually leading to a new Yuasa battery installation (which was due). New batt in, got a few good starts, no problem. Then, next day, no joy on restarts.

So I used a good quality charger to top the new batt off overnight. Then reinstalled and checked battery, all readings with ignition on, post spool up, 12.1 V plus. Attempted start, a few worked then not.

Disconnecting head lights gives a bit more power, and seems to help with bike starting up no problem, but volts at start are then 12.5V plus, which is getting to be a pretty high battery power threshold. You mention in your Conclusion that once one has good power that issues with the blue starter relay (in my bikes case) while uncommon are easily spotted. How so? Do blue started relays fail in such a fashion?

It would be VERY IMPORTANT that you clarify if you still have the old behavior where the starter will not even attempt to engage. If it does engage but is too weak to start, then the problem is certainly not the starter Relay.

Let me re-phrase my last paragraph you have quoted above to make it clearer:
Once you have eliminated all connections related to starter-battery AND have also proven that a good strong battery will not cause the same behavior as you had before (not even a faint click or attempt for starter to turn over), THEN the next most probable is the so-called “smart” 2nd generation starter-relay (although they do not fail often).

 

A loud starter engagement and also starter seemingly staying engaged may indicate a sticky starter clutch. I had both happen on my high milleage bike.

I hopefully took care of that with crankcase cleaner to remove the sludge.And pulled the sump to further clean.Hopefully......only 7Ks since but so far so good.

As for the starter relay, yes mine went dead a few years ago.And yes there has been a few the same over the years.Usually traced back to previous attempts at starting with a lowish battery.Doing that will shorten the life of the blue starter relay.

 

Ah, very interesting, thanks, never a shortage of new tasks to do on these machines!

 

Do you have a motoscan app or gs911? Or heck, even your voltage meter? Check the running voltage to make sure it's charging correctly. You mentioned it would start ok with topped off battery but after a few starts behavior returns. Would seem to indicate charge isn't staying up. Don't know spec for sure (not somewhere I can check) but running voltage should probably be in the 14 range.

 

No start whatsoever, checked voltage, new batter kicks out 12.7 old battery kicked out 11.7.

 

First off, what year and model is your bike? (I'm guessing from your username that it's a 2001 and therefore an RS, but I just want to confirm.) If you've checked the easy stuff (battery and relay) then it's time to dig a little deeper, but we need to know which wiring diagram to look at since they vary by year.

Have you checked the clutch switch? The starter relay coil normally grounds through this. My Clymer manual suggests that the later ones can also ground through the neutral safety switch but the earlier ones (1998-2002) can't, but I haven't personally confirmed this, and unfortunately my '98 is taken apart so I can't test that right now.

 

Jip, 2001 model, the way it died gave me the impression that it's a loose connection, as it had started on and off before I had no crank at all... If that makes any sense... I've gone through the side stand and clutch wiring bridging the wires to make sure that they can be eliminated from my search but if you have any other suggestions as to where to search.
I've cleaned all the contact points on the earth and the battery. I'll have to dig deeper on this clutch.

 

I've tested the clutch switch took it out and cleaned it, tested continuance on it and all appears good. Come to think of it, before this problem happened, I wasn't able to start it in gear, clutch pulled and side stand up. Also followed the wiring from the starter relay and tested continuance with no new answers.

 

So my last thought was maybe the new starter relay was faulty, luckily my Bavarian friends was open to the idea that electronic parts can have a defect... And ordered me a new one. Just tried it, still dead... No crank. Back to the drawing board. Ps. Did check clutch switch for continuance and made sure the start button is good. Also side stand switch tested and good. As well as the kill switch is checked. Any more suggestions will be appreciated.

 

Bad starter?
If you take battery + with a jumper cable and apply it at the splitter connector,the one by the fuse boxes the starter will spin and crank.That could tell you if it is good or not.
I don't have a pic handy, I am sure Jean will.

 

Thanks for getting back!
Nope, starter also good, that's how I got to the starter relay being defective. The starter being bridged to the battery runs beautifully, then I took the cap off the starter relay (blue box) and closed the sollinoid manually, that runs perfect, this electronic fault finding is getting me more baffled. I am just to far out with the bike not running to get it to BMW for a diagnostic test.

 

I just reread your earlier post, no start in gear clutch pulled in previously? I had a problem with the gear indicator switch, one of the fine pins in the connector got bent when I reconnected it.Neutral light stayed on and only started with the clutch pulled in,not exactly like your symptoms but may depend on which connection is compromised?
In any case and if that wasn't done them connectors should be inspected as part of routine maintenance,they may corrode.

Also if I remember correctly there is a diode somewhere in that interlock neutral/sidestand etc..circuit? I think the wiring diagram shows it, but I saw mine in the wiring just around/by/under the relays.Easy enough to check diodes with a multimeter.

Diode markings on electrical diagrams:

Yeah....I have been spending too much time lately checking diodes/solenoid,relays and switches on a Takeuchi mini excavator,but all good.Way worse than the K as to access to work on,I'd rather pull a K starter out than a solenoid on a Takeuchi!

 

Latest feedback, from all I tested all seem to be good, tried looking for spark during a battery starter bridge... None. Then also tried push start with the switch on off tip as in the earlier comments with again none. I have however realized how heavy the bike is to push around.

 

Please, please, if anybody has any more suggestions for me as to where to fault find please let me know. I'm in serious need to ride again.

 

I still require help, haven't taken the bike to BMW yet, still trying to help myself, I've started using my old starter relay to turn the engine, by removing the blue cap on the starter relay I can manually close the contact and the starter runs, but no start, then I checked for spark with no luck, not a single spark. Where do I go from here myself? I know I should just take the bike to BMW but I don't have the resources available yet.

 

So when you first turn the ignition on does it go through (begin) the ABS self test by running the servo motors momentarily and do you hear the fuel pump run to pressure up the fuel system?

 

In reference to the last post it sounds to me like it thinks it's either in gear, or, the kill switch (under the starter button) is not in the center position (run).
In either case upon turning on the ignition key the ABS pump/servo should briefly cycle and the brake warning light should flash, but, you won't hear the fuel pump run and it won't crank.
So does it think it's in gear???? What does the indicator on the dash say? If it says 0 you can probably eliminate that which leaves the kill switch. Your sure it's in the center run position right?

 

Yes, ABS and diagnostic on the key turn is all as it should be, even fuel checked... I've opened the kill switch and tested the the wiring right through to the starter relay to make sure there is contact. I'm running out of ideas and still have the feeling it's something small... It was in neutral through all my testing and currently in 6th as I tried to turn the wheel for start. I couldn't find any fault on the Neutral switch either.

 

Well.... When my Dodge Ram pickup was exhibiting very similar symptoms it ended up being the powertrain control module (PCM).
Without looking back through all the previous posts, have you checked it with a scan tool (GS911 or Motoscan) to see if anything shows up? Although, when the PCM in my truck went nuts it didn't throw any codes. Still worth a try.
If all other electrical and wiring possibilities have been eliminated I'd be tempted to find someone with a good used motronic PCM just to plug in and see what happens. . Make sure it's grounded properly.

 

Well.... When my Dodge Ram pickup was exhibiting very similar symptoms it ended up being the powertrain control module (PCM).
Without looking back through all the previous posts, have you checked it with a scan tool (GS911 or Motoscan) to see if anything shows up? Although, when the PCM in my truck went nuts it didn't throw any codes. Still worth a try.
If all other electrical and wiring possibilities have been eliminated I'd be tempted to find someone with a good used motronic PCM just to plug in and see what happens. . Make sure it's grounded properly.

Thanks, I'll have to get it to my local BMW for a diagnostic... I'll have to save up a bit to get it on a bike trailer and take it to BMW. I'll definitely get back with the problem as soon as it is done, hopefully it can help someone else in the future.