The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: andrelitinsky on June 25, 2019, 08:02:07 AM
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Fellow Airheads,
This past weekend I spent all of Saturday troubleshooting and working on my 1982 R65 at the Culpeper, VA Airhead Tech meetup. I got to meet some awesome and passionate people. The tools and resources were insane:
(https://i.imgur.com/KCWHvlm.jpg)
The main problem right now is the left cylinder is cold and not firing. Occasionally, the cylinder has pre-ignition and the ping is so violent - it knocks the carb off. The bike runs great but just on one side.
If you look closely, the pings in the video knock the carb off yet the bike still is able to run.
[flash=]https://www.youtube.com/watch?v=J2HKwIr3qUY[/flash]
(sorry for the shakiness, the bike was vibing the phone)
The bike has Mikuni VM34 Round Slide Carbs jetted at:
Needle: 6DH3 | 3rd Slot
Needle Jet: 159-P0
Main Jet: AB180 -> moving to 210 (according to Bill @ Rocky Point Cycle)
Pilot Jet: 35 -> moving to 40 (according to Bill @ Rocky Point Cycle)
Slide Cut: 3.0
We have eliminated the following problems:
Valve clearances - set to 0.008|0.004
Compression - 120 psi each side
Leak down - no leakage
Spark plugs - gapped and arcing
Carbs - we switched LH/RH carbs and same problem occured - right side was firing and hot - left side cold
Checked distrubtor & cap resistance
Removed exhaust and checked for air flow
More information:
The bike was cranked over several times with the ungrounded and empty caps.
The bike was able to idle and static timing was checked (with strobe light) on the left side.
Is it possible to show 'S' for static timing on a side that isn't firing?
When running 2-3k rpm, the right side would be close to ~2x hotter than the left side.
Near sunset, we were advancing/retarding the Motorrad Hall Sensor and it felt like the left side began to fire a bit.
[flash=]https://www.youtube.com/watch?v=17J-mj2by2I[/flash]
Thanks to everyone at the meetup!
Suggestions?
-Andre
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left side has a flat cam lobe on the exhaust
Take the valve cover off and try to compare the valve lift with the intake
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Is it possible to show 'S' for static timing on a side that isn't firing?
Yes
you are seeing the spark that is going to both side every time the pistons come to Top dead Center regardless of what side the timing light is hooked to
That is why they call it a wasted spark system
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Did it run correctly before the Miks?
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Did you replace the spark plug? Sometimes they work in air but not under compression
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So last night I jetted the carbs to recommended specs from Bill @ Rocky Point Cycle, replaced the fuel lines (with nice cloth covered ones), replaced the 3D-printed rubber boots that go on the intake/exhaust of the carbs. I was feeling confident in the bike. The next thing, I checked for spark on both plugs. Then fired her up!
Same thing - LEFT side was colder than the right side, heard some pings.
Then I switched spark plug caps, cooled her off, and waited. While doing so, I noticed the RIGHT side was running lean (the plug was white and extremely hot). I only ran for about 2 minutes at 2-3k rpm. LEFT side had wet spark plugs.
Once cool, I fired her up wuith the swtiched spark caps and guess what?
The RIGHT side was now cool and I believe there was some pinging on the right side too.
So I have everything dialed in from a mechanical standpoint. I am getting spark, but when I switch caps, the problem switches sides (I will do a couple more trials to be 100% sure).
Does this mean something is wrong with my ignition coil?
It doesn't make sense that I am getting spark on both sides though.
I am currently running the Brown 1.5 Ohm Dyna Coils and the ALPHA Ignition System V.3. from Motorrad (that comes with a Hall sensor and control unit). Is it possible my control unit is messed up?
Thank you guys in advance.
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I'd be looking at the spark plug lead and cap as the fault. Replace the one with the wet plug as it is not always firing the spark plug.
Then go back and look at the tune of the entire engine.
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If you still have the single dual output coil, the coil is not the problem .
Both plugs fire at the same time .
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I switched the caps around and even tested them on my buddies R65. Caps are good. Spark plugs are good.
I then switched the spark plug caps on the coil-end. The problem switched sides, meaning the left side was firing and the right was cold. Switched it again (coil end), right side was firing left was cold.
Does this mean the culprit lies in the coil?
Is it possible to be in the Alpha Ignition Hall Sensor or the Module?
Can someone please explain to me what the Hall Sensor does and what the Module does?
How can I bench test the Brown Dynatek 1.5 Ohm Coil?
Also, when removing the Dynatek Coil, I forgot to disconnect the battery. In general, when working with the electronics, should you have the battery disconnected?
We're close, but I need your help!
:)
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Can someone please explain to me what the Hall Sensor does and what the Module does?
The module is just an electronic switch which contains some circuitry to interface with the hall sensor and a large power transistor that actually does the switching. The hall sensor triggers the electronic switch to open at the correct time to initiate the spark.
How can I bench test the Brown Dynatek 1.5 Ohm Coil?
Also, when removing the Dynatek Coil, I forgot to disconnect the battery. In general, when working with the electronics, should you have the battery disconnected?
It's easy to test the primary side at it should measure approx.1.5 ohms. I don't know the exact spec but the secondary winding measured between the two HT connections should be something in the region of 15,000 ohms.
If the ignition is turned off there is no need to disconnect the battery when working on the coil or module although you would want to do it before removing the front timing cover to access the hall sensor as there is a short circuit risk.
First question deliberately last. I'm struggling to see how a dual output coil like the dyna could fail completely on only one side. When you said you checked the caps was that independently of the ignition leads between cap and coil as the plug cap might be fine but the lead could still be faulty.
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Check continuity from the secondary winding to the core
95 percent sure you will show some kind of continuity
It should read infinite
If it does not read infinite it is BAD
I have a Brown Dyna coil that did the same thing you describe
It would only run one cylinder at a time
It was shorted to the core
Even if it doesn't show shorted try a different coil any way
It can sometimes be difficult to test a coil since they operate with such high voltage and a Volt Ohm meter works with a very low voltage
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"I'm struggling to see how a dual output coil like the dyna could fail completely on only one side."
Barry
the secondary winding's short to the core closer to one side than the other
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UPDATE:
Replaced the ignition coil, the bike is finally running!
I am sitting at a 1250 RPM idle, so I need to figure that out, but nevertheless, this is the most progress I made in 3 months.
In other news:
I ran my finger through the air filter box, right where the air intake meets that metal ring, and it was very grimey. Do you reckon its worth cleaning/replacing? What have you guys heard about those small attachable air filters?
Thanks.
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UPDATE:
What have you guys heard about those small attachable air filters?
Thanks.
Pod filters that are basically attached to the carbs instead of the original tubing? Not practical or worthwhile for daily driving; they drastically change the airflow and require tuning the bike away from stock.
As long as the underside of your air filter (the part closest to the carbs in the path of airflow) is relatively clean, it's probably fine. You could clean out the air chamber if you really wanted to, but it's probably not necessary. I think I've changed my air filter once in 40k miles or something.
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UPDATE:
What have you guys heard about those small attachable air filters?
Thanks.
Clean it
On top of what Matt said about the Pod filters
They tend to make the carbs fall off because the rear of the carb is no longer supported
And then you have to deal with the oil vapor that is coming out of the crank case breather that no longer is directed into the elbows