The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: guyom on August 14, 2017, 09:05:09 AM
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Hi Guys, question for you : i ran with my bike (R65 1981) and suddenly.... the engine starts to misfire, i mean the idle was ok (well the for problem) but since i started to accelerate... rattatatata tapouet pouet poufff... i can restart the bike a bit... but finished the run by pushing the bike :-) (nice bike to push by the way not too heavy ;-)).
So my guest is the ignition coils... is it possible that the coils shout down? other idea?
Other questions : no link with the first one : i found a grease pump on my garage. Does the R65 need grease somewhere?
Finally, i read that the weak point on BMW bike are the oil pump (a clapet on the oil pump) and the exhaust valves. Is it hard to change by yourself or a mechanic guy is required ?
Thanks for time
Guillaume
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Do you have a black and gray ignition coil ???
It's a known problem with these bikes .
About the only thing you can grease on an R65, is the swing arm bearings .
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For greasing it may depend on the year. My 79 has grease nipples on the gear shift lever pivot and on the clutch operating arm at the back of the gear box. Plus as Bob said the swinging arm for which you need a conical tip on the grease gun.
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HI guys, thanks for answer.. indeed.. i have an interesting "Harley Davidson black ignition coil" on it so far from stock... i was on the bike when i bought it... so mystery. I will check it tonight.
Just to know for a 1981 June model, does the DYNATEK DYNA DC2-1 1.5 OHM BROWN COILS is a good option ?
Thanks for the grease.. i will check the swinging arm.
Guillaume
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Yes, brown coil is fantastic!
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I am making the assumption that being a 1981 edition that you have a hall effect ignition system.
Are you really sure the coil is the problem? It may be a peripheral problem but not the immediate cause.
Sudden stops of a previously well running bike and then subsequent ability to run at low revs but not at high revs are symptomatic of a failed ICU.
The ICU (unless it is the very latest riveted model) should be removed every couple of years and the thermal transfer paste renewed.
The wrong coil will also cause premature failure of the ICU, I don't think the Dyna green coil is the correct resistance for the ICU. For an insomnia curing discussion of all things ignition it is worth reading snowbum on the topic.
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I think the green is for the early points ignition and the brown for the 81 and later...
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Yes, the green coil has slightly higher primary resistance, which wouldn't be a problem for the solid state ICU, just might have slightly less spark energy but should still run OK... but this Harley Davidson Black coil is an unknown entity.
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I have not heard the oil pump being problematic as a mater of fact just the opposite is true
Generally they have very high oil pressure to the point that to high a viscosity oil can crush the oil filter
Yes the exhaust valves are problematic but that depends on how much you ride
Are they closing between oil changes (7500 KM)
Not only do the valves fail the valve seats wear out also
You can remove and install the heads yourself
But the valves are not something you can repair yourself
The heads have to be sent to a machine shop to be repaired
Green (3 ohm)coil can be used with Points and either new or old style ICU
Brown (1.5 ohm)with both new and old ICU but not with points
Blue (0.7 ohm) with only the newest style ICU
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To get to the oil pump, you have to remove the gearbox and clutch assembly.
Odds are, it is fine. Most folks, if they are in there for a rear main seal r/r, will replace the o-ring on the oil pump cover.
At some point, if you keep this bike long enough, you will learn to do all of this. Do you have the original tool kit and owner's manual? BMW gives you a very good head start on ownership with these two items. MUCH better than the competition.
edit: AH! Clapet! I had to Google it.
Yes, there is a spring-loaded bypass valve in the oil filter compartment. I have heard of the spring breaking, and the spring pieces can get into the works and really mess up your day.
Here is some discussion about it on Boxerworks forum:
http://forum.boxerworks.com/viewtopic.php?f=1&t=1046&p=12703&hilit=ball#p12703
and
http://forum.boxerworks.com/viewtopic.php?f=1&t=217&hilit=oil+pressure+spring
edit 2: if you have signs of oil weeping around the filter cover, DO NOT tighten the fasteners tighter! You could easily strip the threads in the engine casting!
If you do have weeping, you might need to read this article about how not all oil filter canisters are installed to the same depth.
http://www.gunsmoke.com/motorcycling/r100rt/oilFilterCanister/index.html
The idea is to measure things, and amongst the paper gasket, metal washer and rubber o-ring, you can adjust to get just the right "crush" on the o-ring to make things tight.
In my case, all I had to do was quit using the paper gasket, and all was wonderful with the world, or at least, that small part of one motorcycle engine...
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Hi Guys. Many thanks for the answer. i checked with a voltmeter yesterday evening from one cap of coil wire to the other and had 21,28 kOhms. so obviously, looks correct (should be between ~17000 to ~30000 ohms). So perhaps the ICU module.. but i do not knoww how to test it.
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does anyone test this model:
https://www.euromotoelectrics.com/Ignition-Module-BMW-R-Airhead-12-14-2-325-284-p/ignmod-r284.htm
is it a good option to change the stock ICU ? and in complement to brown Dyna coils ?
Guyom.
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It should be. You can contact them to be 100% sure, he's one of the good guys!
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So i contacted the guys and yes that works however he suggests to use the Blue Dyna coils DUAL TOWER IGNITION COIL, BLUE - 0.7 OHMS RESISTANCE / DYNATEK and not the brown one to have the same resistance as Bosch dual tower coil or the early gray version. so technically Blue Coils and HEAVY DUTY IGNITION MODULE should work fine.
Guyom
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Good to know. As far as ignition modules I think you can go to a junk yard and grab one out of an old Volvo, same thing...
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Hi Guys. Many thanks for the answer. i checked with a voltmeter yesterday evening from one cap of coil wire to the other and had 21,28 kOhms. so obviously, looks correct (should be between ~17000 to ~30000 ohms). So perhaps the ICU module.. but i do not know how to test it.
That doesn't mean it is definitely good
It can still be bad
Check continuity between the primary and secondary winding's
It should be infinity
I have a bad Brown Dyna coil that will only run one cylinder at a time
When checked with a VOM the primary and secondary winding's show OK by themselves
But it is shorted between the primary and secondary winding's it has 20k ohms between them instead of infinity
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HI all, so here is the last update : i confirm and reconfirm with Euromotoelectric: (by the way really friendly). :
Hello,
It looks like models from 1980- 1984 had a coil with a resistance of 0.7 ohms.
Then for a short time, BMW used a Bosch coil with 1.5 ohms resistance, (gray bosch coil known to crack) then back to 0.7 ohms with the newer Bosch 426 coil, which is the one we sell, and the latest design from Bosch. This coil works best with our ignition module 12 14 2 325 284 (with heat sink)
So, since your vehicle was made in 1981, it would seem as though your stock coil should be showing 0.7 ohms and should work well with the BMW ignition module ending in 284.
So want to confirm that Blue Dyna combined with 12 14 2 325 284 (with heat sink) and the answer is : YES.
Good to know i will test that. Perhaps the erratic file come from the match between the Harley Davidson Coils and the stock ICU.
Final question : what is the difference between a 0,7 ohm, 1,5 ohms or 3 or 5 ohms coils ??
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Final question : what is the difference between a 0,7 ohm, 1,5 ohms or 3 or 5 ohms coils ??
The primary resistance determines what current will flow to energise the coil.
Using ohms law the nominal primary current will be:
5 ohms 2.4 A
3 ohms 4 A
1.5 ohms 8 A
0.7 ohms 16 A *
* By the time resistance gets this low the actual current will not be as simple as saying 16 A because the wiring resistance becomes relatively significant and also the ICU is likely to have a built in current limiter.
The theoretical reasons why lower primary resistance was pursued are two fold:
Lower primary resistance brings with it lower inductance and that makes the coil reach saturation quicker with benefits at high revs. For example with 3 ohms the coils didn't reach full saturation at mid to high revs.
The 2nd reason is to increase spark energy which = the primary current squared times 1/2 the inductance. Thus a low resistance low inductance coil looses a little because of low inductance but gains much more from the increased current.
Note I said "theoretical" above. In practice all versions of the airhead ignition seem to work fine. While there is no doubt that lower resistance coils do produce more spark energy the question is whether or not it was needed.
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thanks Barry for the electricity lessons.. !! i like to understand the "why".
Is it why the recommend to have a 16Ah battery on the bike (if 0,7ohms give 16A ?) By the way i bought a Battery in BMW shop and they sell me for this model a 24Ah....
Well...
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Battery capacity is not really related to ignition coil current.
You can use any battery that fits the space. There are a some generic AGM batteries that can be 18, 20 or 22Ah but all the same physical size.
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Just to warn you If your original ICU mounting bracket looks like mine
You will have to make your own mounting bracket to make the newest heavy duty ICU fit
The adapter bracket that BMW offers will not work because there is no where to bolt it to
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thanks for news... ok for the battery and thanks for the warning for the heavy Duty ignition module. Technically i redo the wiring for the bike with a M-Unit from Motogadget and install a RR45 regulator so nothing except the ICU is stock ;-) So why not finish the job with you ignition system.
Thanks for time !
PS: i found a ground wire loosen... so perhaps that explain the situation...