HELP - 1981 R65

[Mick]

Hello all,

A problem I cannae work out. Pionters in any direction will be much appreciated, and if anyone recognises this then so much the better . . .

so I'm toddling along yesterday and suddenly, for no apparent reason, the engine dies then quickly re-ignites. The rev counter goes right to zero, but no lights come on on the console. Must be electrical no? I stop and have a wee look through the BMW manual. There's nothing describing this in the 'troubleshooting' section. I have a wee look around the electrics for loose wires, find none. Put it all back together and away it goes.

But then, in town 40miles/60km later, just as I'm getting to where I want to go, it splutters again, but it gets me to the hostel and I promise it some oil in the morning. (It was very low!)

It takes 1litre(!) of GTX in the morning and off we go happy as . . . 20miles from destination (90miles/140km later) it starts again. Another look around the electrics is fruitless and so I check connections are tight and decide to go over them all with some WD40 and some vaseline as soon as I can get them, some shade and peace.

But the whole thing worsens majorly just as we enter Cartagena. It won't pull away and won't rev over 2500rpm. Cuts out then quickly refires - like kangaroo petrol. Then there's some backfiring and some sharp cracks from the top ends, but it's still running! Can't find the hostel like this so I leave it in a car wash and hope it'll still be there in the morning!

What have I done? Any ideas? Still to go over everything with the WD but if it's something you've heard of before I'll be very grateful for your info! We sail from here in 9 days.

All best things,

Mick

 
 
 



(edited to put year/model in title - RV)

[Semper Gumby]

Hi Mick.
 
You have a short in one of the leads that goes to or from your coils (maybe).  Get out an electrical diagram and start tracing wire.  I had this problem after my front coil mount broke and one of the leads on the coil started grounding to the inside of the tank.  The sharp report you hear is the fuel air mixture (unburned) pumped into the mufflers igniting  (like a rifle shot) when it is followed by hot exhaust gasses when the ignition starts firing again.
 
I understand that the Grey coils on the later R65s may crack and fail (but does this sound like what is happening?)
 
Good luck.  I removed the broken forward coil mount on my 1980 R65 and replaced the aft coil with a single Dual wire Dyna Coil mounted on the aft mount.  This works quite well with no cutouts and no backfiring (no shorts).
 
Others chime in with whatever I missed please.
 
Bill  

[Justin B.]

You have neglected to give the year, but if it is an '81 or newer maybe the coil is starting to die?  Or, had you maybe recently filled up, maybe got some water?  Try draining your float bowls to make sure no crap or water is in the bottom.  On another tack, our '80 would cut out for a couple of cycles every now and again and after cleaning all the electrical connections, and running the aux ground strap between the frame and forks, it never happened again - but we had none of your other symptoms.

Maybe one of our Aussie brethren might be close enough to you to maybe loan a coil to test with?  At least, it's doing this ALL the time now so will be a lot easier to troubleshoot than an intermittent fault.

[Bob_Roller]

Well, I think Australia is a bit far away , Mick is in Columbia.

[Justin B.]

Not sure where that is but his reference to "kangaroo petrol" and metric measurements led me to assume...

[Bob_Roller]

If you go to the rides section and look for the posting R65 Registry, it will get you to a link about this R65 owner going around the world on his bike. Interesting reading.

[Justin B.]

I'm not that ambitious right now, going to bed.  Maybe tomorrow...

[nhmaf]

My first steps would be to examine the coil and spark plug leads, and test with an ohm meter.
*Usually* (but not always) when something comes on this quickly it is electrical in nature.
If the coils and leads all check out, I'd check the connections to the fuse panel and fuses
next, and then progress to the carbs.   If none of these proved to turn something up, you
might have an intermittent connection on the diode board or in the ignition control (bean can)
though that would be much less likely.

[seniorchiefSS]

I had a similar problem on my kawa 1500 and it turned out to be the neg batt post connector loosened. it was tight when I twisted with my fingers to check but needed to be tightened with a wrench. I drove thru the city backfiring and felt very foolish when the mechanic found this problem.

[Ed Miller]

nhmaf, could a bad diode cause ignition problems?  I thought it was basically a voltage rectifyer, but the BMW way does seem much more complicated than what I'm used to.  Heck, maybe he has a bad spark plug, though only one shouldn't make the bike die.  

[MrRiden]

Mick,
Heres what to do.
1). Pull the tank
2). If you have the Grey coils check for cracks and replace if any found. This won't solve the problem but you need to do it anyway.
3). Locate your electronic control module. (your location may vary)
4). Remove, clean and apply heat sink paste.
5). Take a ride (anything under 100mi or 160.93km is not a ride)
See the following for more detail
http://www.webbikeworld.com/motorcycle-maintenance/ignition-heat-sink/
Can you tell I just watched a rerun of http://www.fox.com/house/?
Rich

[nhmaf]

Ed,  

It is not likely that a bad diode would cause ignition problems, but if a diode
is beginning to fail it could cause intermittent battery charging and widely
fluctuating current that might not be visible on the gen light or voltmeter gauge.
This can sometimes result in damage to the regulator or battery.

I was thinking of a more likely scenario like a wire from the ignition can/HE sensor possibly shorting
against something (diode board, case, or other such thing) under the engine cover as
a possible cause for misfiring ignition.  The hall effect device itself can fail and cause
bad ignition timing, but their failure rates are generally very, very low, and it makes sense to
check and rule out everything else first before testing them.  

[trolle]

It does not sound like a failure in the hall device. If that fails you will at first experience a failure to ignite at one side and very shorly afterwards a total ignition failure. Anyway that is how the wh8la2 behaved after my first two miles on her!

greetings from a warm and sunny north

trolle

[thrang]

Sounds like a short somewhere in the ignition circuit to me.... So before I started worrying about anything expensive I'd check the ignition  wiring for any wearing, and the kill switch on the handlebar. If h/bar unit is old then there could be a dry joint on a connector or a cracked wire inside the plastic sheathing.
Tony

[Bob_Roller]

I recieved an email from Mick today, and the problem appears to be the 'bean can', he has the can, icu and a coil on order from Bob's BMW, and looks like he'll get the parts when he gets to Panama. He's got the bike secured to the main mast on the ship/boat he's taking from Colombia to Panama, guess he sails tomorrow morning.