2,350mi 79 r65 tour ends in NO SPARK!

[mendozeal]

Jeff here, with the 79 r65. So everything went quite well on my trip from mendocino CA to Lenzburg, IL.
I will post pics and stories as soon as they are sorted.


I made it 2350 miles exactly, then she bogged out and died. luckily I was 20 miles from my final destination!!! pickup trucked it home.
(A 81 R65 STOPPED TO HELP AFTER 5 MIN OF SITTING!! FIRST ONE I SAW ON THE WHOLE TRIP!! just awesome.. he brought me some fuel line, as that was the first thought. Love all you airheads out there, we will ride together when she is firing!)

after some basic diagnostic today, No spark..
dunno why, gonna fine tooth comb and routine maintenance the electrical system tomorrow. (Start at the condenser/contact point) But I was wondering If I should just throw some new relays and breakers at it, and see if it sparks.. you seem to know better then anyone else, so let me know what ya think.

it was sunny and dry when it died. it sputtered twice, about 20 miles prior on the highway, then rode fine. for 20 min. then bogged out and died. felt like a fuel problem, by how gradual it died. I pulled my fuel filter (only used for the cross country shitty gas risk) and replaced the air filter housing section of fuel line (in case of melting). I checked fuses, I replaced the 12v relay (shitty napa universal) and cleaned plugs and caps. then got lazy, going to pull the front and starter cover now.

and if you think I dont need to replace relays where would you start?

any ideas will be appreciated, this is my favorite way to work on her, with your ideas!

thanks for your help!
Jeff

[Barry]

and if you think I dont need to replace relays where would you start?
 

Jeff

1st place I'd start is to check for closed up points. If they are closed flick em open with the ignition on and check for a spark at the plugs. They are not that accessible in the bean can so you may have to remove the outrigger bearing plate to get at them for this test. It can be done with the bearing in place but you would need something thin and ideally an insulator like a wooden cocktail stick.

[Bob_Roller]

I'm assuming that you have dual round coils, the forward coil mounting bracket has the main grounding point for the bikes electrical system, it is not uncommon to have this clamp/bracket crack, when it does fail, all sorts of electrical problems can occur .

It's a quick check, once the fuel tank is off.

[mendozeal]

ok, going to check my points now, Im assuming I have to remove the whole bean can to have access to the outrigger bearing plate?
(or is the outrigger bearing plate the infinity sign shaped thingie in the very front of the open bean can (because that was the first thing I pulled, super easy and I have done it before..) and as far as points (newbie warning) it is just the contact set inside the bean can right? when it opens it sparks is my understanding... am I right?

also I pulled the shit for 2 6v round ignition coils, and  replaced it with the dynacoil green (12v single 3.2ohm dual plug) works like a dream, but it is possible my ground shook loose, where exactly should I check now, is it the ground loop uner the tank to the forward left? (just a bolt hole welded to the frame)

checking now and will report back soon, THANK YOU!

[Barry]

or is the outrigger bearing plate the infinity sign shaped thingie in the very front of the open bean can (because that was the first thing I pulled, super easy and I have done it before..) and as far as points (newbie warning) it is just the contact set inside the bean can right? when it opens it sparks is my understanding... am I right?
 

Yes. Right on all counts. When the points are closed a current flows to "charge" up the coil and when they are opened by the cam the plugs spark. You can simulate that by rotating the engine until the points are closed then flicking them open.

Don't  leave the ignition switched on for more than a few minutes with the points closed or you will overheat the coil.

[79beem]

Disconnect the battery before you pull the front cover off, otherwise you might short out the diode board.

[Rob Valdez 79 R65]

From the factory, the main ground for the harness is a standard sized BROWN wire.
It should be on the right side of the main frame near the front.
It was originally fastened to the front coil mount (as Bob said) and if that mount is broken or even cracked, it can cause the symptoms you describe.

Here is my solution:

[nhmaf]

Also, since you've just done a long ride, I'd recheck that your valve lash hasn't closed up on you - that can cause hard starting, inability to idle, and loss of power.   As your bike is still 'relatively new' to you and you've just made a series of fairly long distance days, I'd check this too, along with the points/condensor.

IT is fairly unlikely that a relay is causing this.

[Rob Valdez 79 R65]

Also, since you've just done a long ride, I'd recheck that your valve lash hasn't closed up on you

VERY good, Mike!

I forgot about how my bike died when I pulled into a rest stop on a road trip.
I managed to get it started, and it would run as long as I kept the revs up, but when I checked the valves the next morning the left exhaust had NEGATIVE clearance!

By the time I had gotten home (420 miles later) the clearance was again significantly reduced.

[Red_Hen]

Sparrow,

What's the update?  Interested to know how you're doing?

[mendozeal]

sorry shotty interweb.

contact set. Plus red n tacky #2...
 red n tacky #1 failed under heat on the front cam, (or I didnt put enough on (more likely)) and the rubber for the contact set broke.
no gap in points = no spark!
contacted rick at motorad electrik, and had the part two days later. running like a dream again. I checked my clearence anyway, and it had closed 0.05mm, if that... so I re adjusted, and she appreciated it...

thanks for your help guys, I used a shish ka bob stick to check spark. so scientific! (AND A METER TO DOUBLE CHECK MY LINES!)
 another problem successfully solved, thanks guys!

[Red_Hen]

Sparrow,

Glad you figured it out and hopefully will return home safely from the Midwest before the snow flies.

So, how did you figure out what the problem was?  Also, you mention yours bike has a bean can.  I thought the points in a bean can don't need setting.

Just curious to know the details.

Ken

[Rob Valdez 79 R65]

Also, you mention yours bike has a bean can.  I thought the points in a bean can don't need setting.

You are confused Ken.  The points in a bean can on a bike like yours don't need setting.  

[mendozeal]

yeah and settin it is not rocket science.... ive been told as long as they open it runs, I just check it with a feeler gauge at TDC.

I think she will be returning on trailer, I want to buy an RV and there is a real beauty sittin right in front of me. However, If the toyota v6 rv wont accomplish this realistically I may just sell, after the restore, Im bound to get more out of it anyway... check the trading post!

[Barry]

ive been told as long as they open it runs, I just check it with a feeler gauge at TDC.
 

It's true within limits that the gap is not that critical. Anything between .014" to .020" should work OK. The gap must be set at maximum opening and that is a little past TDC.

If the points gap is too big it reduces the dwell time, that is the time available to charge up the ignition coil to saturation. Not a big issue on a 2 cylinder engine like an airhead but there are limits.

The gap being too small is much more of a problem and will result in a weak spark at the plugs or no spark at all. Ignition points are just an electrical switch and like any switch one of the critical design parameters is they must break the circuit and quickly extinguish the subsequent arc. When you open any switch an arc is produced between the contacts. Switch contacts must open fast enough and far enough apart to break or extinguish the arc. This is why switches are sometimes called circuit breakers. Getting back to ignition points if the gap is reduced below the design specification the arc is not extinguished quickly enough leading to a weak spark and eventually when the points arc is not extinguished at all you will get no spark at the plugs even though the points are not completly closed up but still opening a few thou.