FORUM

Notifications
Clear all

1982 R65 Timing Issue

8 Posts
2 Users
0 Likes
3,854 Views
Andre Litinsky
(@dretek)
Posts: 24
Eminent Member
Topic starter
 

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:

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.

(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.

    Thanks to everyone at the meetup!

    Suggestions?

    -Andre

     
    Posted : 06/24/2019 13:38
    Richard Whatley
    (@wobbly)
    Posts: 2499
    Member
     

    Your bike isn't "pinging" at all. It's actually trying its best to run on the left cylinder. In fact it does run quite a bit. That can be plainly heard in the video, which is excellent. Thank you.

    The test of swapping the carbs is a good one, and only leaves the ignition at fault. Since the ignition unit fires both sides at the same time, the only discrete parts are the coils, plug wire, plug cap and spark plug. Next test is to swap the plug wires in the coils. That is, make the right coil fire the left cylinder. I bet you'll find something.

    Supporting evidence was the fact that you allowed the bike to turn over without plugs fitted to the plug caps. That's a BIG no-no. You'll literally burn up a coil doing it that way.

    (A new set of plugs wouldn't hurt either. I don't care if the ones in there are only 2 days old. Ethanol gas is no friend of spark plugs. )

    Hope this helps.

    [color=blue]Don't hide 'em, Ride 'em !!
    #15150[/color]

     
    Posted : 06/24/2019 21:34
    Andre Litinsky
    (@dretek)
    Posts: 24
    Eminent Member
    Topic starter
     

    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.

    P.S. One thing I need to try and I'm just reminding myself:

    Switch Caps
    Pull Throttle Cable on One Side - LISTEN
    Check Plugs
    Repeat

     
    Posted : 07/03/2019 08:01
    Richard Whatley
    (@wobbly)
    Posts: 2499
    Member
     

    And did you install new plugs ?

    Look, plug wires, caps and new plugs all together total under $20. Why don't you stop all this foolishness and simply replace those items ? The bike is 35 years old, and those items will need replacing soon anyway. You're not saving any money by delaying. All you're accomplishing is to waste good riding weather.

    While [waiting on the engine to cool], 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.

    A plug will not take on meaningful color in 2-3 minutes. Therefore, you do not have enough data to make a determination of lean/rich. All you know is that the side that the engine is running on is burning cleaner than the side that's not running.... Which is exactly what we would expect under those conditions.

    At one point I suggested pulling on the throttle cables independently. Was that ever tried ?

    [color=blue]Don't hide 'em, Ride 'em !!
    #15150[/color]

     
    Posted : 07/03/2019 17:50
    Andre Litinsky
    (@dretek)
    Posts: 24
    Eminent Member
    Topic starter
     

    I switched the caps and new plugs 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. During these runs - we pulled on the throttle cables. Cold side had no reaction - even spraying starter fluid down the throat of the carb had no impact.

    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!
    πŸ™‚

     
    Posted : 07/11/2019 08:45
    Andre Litinsky
    (@dretek)
    Posts: 24
    Eminent Member
    Topic starter
     

    Thank you so much for the response.

    At work today I took some resistance readings using a voltmeter on the Dyna Coil:
    Primary - 1.8 Ohms
    Spark Plug Insert to Spark Plug Insert - 13.41 kOhms
    Primary to Spark Plug Insert - No Reading

    So I'm guessing the Primary to Spark Plug Insert (which I believe is Secondary?) read 0 because there is a short - indicating the ignition coil is at fault.

     
    Posted : 07/11/2019 15:04
    Andre Litinsky
    (@dretek)
    Posts: 24
    Eminent Member
    Topic starter
     

    UPDATE:

    Finally, after 3 months of tunnel vision focus on the Japanese carbs on the German bike, the problem turned out to be a faulty ignition coil.

    The bike fires up immediately and runs at a high idle of 1250 rpm.

    The next step is to bring the idle down. I have a Uni-syn which measure the airflow pressure coming in. I also had the idea of just intuitively dialing the idle/air mixture screw til it sounds nice and idles @ 1025.

    OR should I go straight for the shorting method described in http://www.vintagebikebuilder.com/mikuni-tuning-and-jetting-guide.html (towards the bottom there is a paragraph called Dual Cylinder).

    On another note: I ran my finger through the Air Filter Lower Box Housing - and it had lots of soot. Is this worth replacing/cleaning?

    Summer is losing days and I am eager to ride! Looking at helmets already!

     
    Posted : 07/23/2019 08:40
    Richard Whatley
    (@wobbly)
    Posts: 2499
    Member
     

    I'd say adjustment while running normally is always preferable over having one cylinder drag the other dead cylinder along. How would you compare the two, especially knowing that when the other cylinder "goes live" the idle speed is going to increase ? Consider that afterwards, when you go to set the idle speed down, you've just screwed up all your tedious adjustments. Also consider you run the risk of burning up another coil, too.

    Set the pilot screws at 1-1/2 turns, set the idle with the engine HOT for smooth to the ear idle around 1000 RPM, then use the Uni-Sync to adjust the slides (via cable adjustment) for even vacuum at around 2500 RPM. Boom, you're done.

    On another note: I ran my finger through the Air Filter Lower Box Housing - and it had lots of soot. Is this worth replacing/cleaning?

    Please name one other part of an engine that performs better when dirty. And there's your answer. πŸ˜›

    [color=blue]Don't hide 'em, Ride 'em !!
    #15150[/color]

     
    Posted : 07/23/2019 10:00

    Advertisement

    Scroll to top