R65 Resurrection

[TomHoldom]

another photo of arrangement beneath tank

[TomHoldom]

Check for good battery  Positive  at the Green/Blue wire at the coil during cranking
check the wire between the coils

Check the spark plug wires
I think they are 1000 ohm caps plus solid core wires


check for corrosion in the   connectors in the ignition system

OK here are the first of readings I have got:
rear mounted coil: 11,48V, reducing to 9,5V while cranking
front mounted coil: 5,88V, increasing to 6,6V while cranking

then testing the spark again, I am now getting
spark from the front coil
no spark from the rear coil.
(I swapped the spark plug leads around and this didn't change the results - i.e. still no spark from rear coil. So I assume those leads are ok)

Also tried to measure the resistance of the connecting cable between the coils, but I can't be sure I was measuring the correct cable as it disappears into a mass of cables bound together, but there is a black and yellow cable between the connection "1" of the rear coil and the connection "15' of the front coil.
I measured a resistance of 0,4 [ch937] which is presumably wrong...?

Interesting while carrying this testing I had a few more pops than I had been getting before (couldn't tell which side), and the spark plugs were just one or two turns into their chambers

Does any of this make any sense......?

[Barry]

there is a black and yellow cable between the connection "1" of the rear coil and the connection "15' of the front coil.
I measured a resistance of 0,4 [ch937] which is presumably wrong...?

Only wrong in the sense that it should be a little closer to zero ohms over such a short length of cable. Multimeters are not very accurate at very low ohms readings so I doubt there is problem. Does the meter zero when the test leads are shorted ?

The voltage readings you took at the coil terminals already suggest that there is nothing wrong with the primary windings of the coils as you would expect to drop approx. 6 volts across each coil.  If one coil is not sparking in spite of the primary winding being OK then I would attempt to measure the resistance of the secondary winding between the HT terminal and either of the primary terminals.  You should expect 7500 Ohms or more.

[TomHoldom]

Does the meter zero when the test leads are shorted ?

Hi Barry, yes meter is at zero when I touch the meter leads.
Isn't odd though to have one rising and the other falling when cranked?
I'll try again to measure the secondary. I managed to read 6540 [ch937] on one, but could get anything on the other.
Can I stick any bit of metal down into the coil HT cable socket to get a connection and then measure from that to either of the primary terminals?

[Barry]

Can I stick any bit of metal down into the coil HT cable socket to get a connection and then measure from that to either of the primary terminals?

Yes that should be fine.

Technically I think you should measure between the HT and terminal 15  because one end of the secondary winding is connected to 15 but in practice it doesn't matter because using terminal 1 just adds 1.5 ohms to many thousands of ohms which is of no consequence.

[mrclubike]

Honestly
I would just replace the points and condenser and replace the 2 coil with one and a fresh set of plugs and wires 
This is just normal maintenance in the days when this bike was new
It was called a tune up
$135 bucks  and your good for another ten years
At least with the ignition 

[georgesgiralt]

Tom,
Go at any car scrap yard and ask for a two output coil from a petrol car. Measure the primary to ensure the value is the correct one for your points. It will cost you around 10 € will be available now and will last a lifetime. If the guy is helpfull, you could choice the one with the better fitting system for your bike.
I devised something with a Fiat  Punto coil (magneti Marelli ) for my Hall and ICU ignition system.
Just my 2 ¢
BTW, did you get the registration papers ?

[TomHoldom]

Update -
took some new readings today -
rear mounted coil: primary res = 1.5 [ch937], secondary 6,54 K[ch937]
front mounted coil: primary res = 1.5 [ch937], secondary 6,58 K[ch937]

Resistance of spark plug leads 5,11 K[ch937] and 4,75 K[ch937]

checked sparks again and the plug connected to the rear coil was still not sparking (as previously).
I had assumed there were no sparkplug issues as they had only been in a few months and the engine only running 20 minutes during that period, but I put in a new plug which sparked and it started up......

So might have been the issue all along?

Started a few times since then and got it running again (though not easily), on the last occasion I had to turn it off as the engine started racing (with no throttle) - carburetor?
actually I subsequently realized that I was simply running out of petrol...

Also noticed that the left hand side of the engine was warmer than the right - could this be something else to be concerned about?

[TomHoldom]

BTW, did you get the registration papers ?

Hi Georges,
I've made a little progress in as much I have decided to go down the "vehicle de collection" route (FFVE)- got the dossier together and ready to send off. This should get me my "Certificat d'immatriculation de Collection" which takes the place of the CoC, then onto ANTS and form Cerfa 13750.
The thing I still need is the attestation stating that light and speedo have been changed which an approved dealer should be able to produce, though I haven't had any positive responses yet...
Speedo is changed, and I just need to order an new lens for the front light - BMWBayer has one for €23,99 (Product.Nr. 6312541) so I'll probably go with that.
I like your idea for sourcing coils from a breakers yard and may look into that if things start playing up again.

[mrclubike]

Also noticed that the left hand side of the engine was warmer than the right - could this be something else to be concerned about?

Yes it is
That cylinder is misfiring

[TomHoldom]

That cylinder is misfiring

So could swapping the spark plug leads and then swapping the coils and seeing whether the fault follows these changes to the other side be a sensible method to see whether this is an electrical problem?

Also, it is the same side that I get a very slow drip from the carburetor if the fuel tap is left on - could this be related to a possible misfiring on this cylinder?

[TomHoldom]

Managed to start this morning, and took it for a short ride (about 2,5km) It's not cold weather
What I noticed on that short ride was that as soon as I tried to turn the choke off the bike would not run smoothly (certainly not full power).
It would run ok again once I put the choke back on.
I tried this a few times during my short journey with the same results.
Once home, I pulled the plugs and both were very sooty.....

Any ideas of what may be causing this???

[tiggum]

Sounds like carburetor(s) may have obstructed passages...

[TomHoldom]

Sounds like carburetor(s) may have obstructed passages...

Is there any particular order I should check for blockages - is it oversimplifying things to think that because a sooty sparkplug indicates an overrich mix, that the blockage would be an air blockages?

Also one other issue I had which I have just remembered, is that while rebuilding the carbs with the motobins kit which comes with 5 'o'rings, (with no indication where they go) I found a YouTube video which indicated the smallest 2 rings went on the idle speed screw and the idle jet.
I couldn't get the smallest ring onto the idle jet (it broke), so I figured I was trying the wrong 'o' ring and so took the next size up (which according the video I watched should have gone onto the choke shaft - and which was spare, as I didn't open up the choke) - as I write this its feeling like this could be at least a part of problem........

[Barry]

I couldn't get the smallest ring onto the idle jet (it broke), so I figured I was trying the wrong 'o' ring and so took the next size up (which according the video I watched should have gone onto the choke shaft - and which was spare, as I didn't open up the choke) - as I write this its feeling like this could be at least a part of problem........

The O ring itself is not going to cause such a big problem but you have given us a possible clue by mentioning the chokes were not examined. I would remove them to check they are correctly assembled as it's possible a previous owner has not done this correctly. It's worth eliminating anyway.

The internal choke disc has a pear shaped slot which should always be at the top of the disc with the narrow end pointing towards the cylinder head. If they are both like that they are correctly assembled.

If chokes are fine then first thing I'd check is needles are in the correct position.

Pic of choke disc below shown in the fully off position.

Can you clarify exactly when it runs poorly without choke e.g does it idle OK but not run correctly at wider throttle openings.