Finally back running again

[Grumpy]

After a week of dead ends, finally found the problem with the bike. Ignition pulse generator was intermittent, would run OK cold, then start dropping cylinders when it was hot. A real pain to track down, first I thought I had some slow jets stopped up, cleaned them and ran great for about 10 miles, then started missing again. Going to try to put some miles on tomorrow, if the blasted rain will stay away for a while.

[_Sheffjs_]

Glad you are back in the saddle again and YOU and the bike are ticking correct. 

[sixlow]

Thanks for posting this Bill, it sounds similar to how my Teal bike runs, sounds great when cold but loses its apeal when it is hot, is there a good way to test this ? Where is it located and how much does it cost ?

[Grumpy]

Thanks for posting this Bill, it sounds similar to how my Teal bike runs, sounds great when cold but loses its apeal when it is hot, is there a good way to test this ? Where is it located and how much does it cost ?

They are behind the front timing cover, pain to check. Supposed to use 10m-ohm recording dc multimeter to measure the voltage, minimum out put of the pulse is 0.07 volt, very hard to measure. I borrowed a scope from my old work place to test mine, the scope would record the pulses and show the voltage.
Cost, I do not know, took one off of a parts motor I have. if one fails you will loose the spark to 2 to 3 cylinders. Mine lost it to 3, rode back from Zhills, and wide open could barely make 50 mph.

[Moofner]

Welcome back to the land of the running. I'll file this knowledge for the future. I'll be picking up my 03 soon!

[TJ]

   

[John Schmidt]

Bill, those things can be a bugger for sure. When I changed out the engine on my 1200 I made sure the replacement wasn't an '84. In '84, the 1200 had those ignition triggers on the back of the engine and you had to pull the motor to replace them. From 1985 on up they're in front like the Valk engines.

As for testing, I'm wondering if it's possible to hook an LED flasher up to that circuit and observe it while riding. Using a low draw item shouldn't create a problem with the ignition and seems like it would give you a quick indication. Isn't Gil or someone in our group well versed in microelectronics, they might have some thoughts on this.

Re. a 1200 engine, I'm watching an item on Ebay now, so far no bids. It's a 23k mile engine but is an FEI setup. The block is all the same and all the mounting bosses, threads, etc., needed for a carb engine are there....just not used on an FEI engine. So, all I'd have to do is yank all the FI stuff and install my carb setup along with the ignition and engine harness, along with those same TW pickups you just had trouble with. I should know something in a day or two, I can't really afford it and can't really afford to pass it up.

[Grumpy]

Not enough voltage there to fire an led, 0.07 volts, most leds require 5 volts to illuminate. I could not even read it with a normal multi meter, that is why I used a oscilloscope. It had the capability to record the pulses on the screen, and show the peak voltage when it triggered.

[John Schmidt]

See, that's what happens to me now when I start to think about something....it usually doesn't work.    I haven't used an oscilloscope for so long I can't even spell it anymore. 

So, wonder if you'd get the same indication if you tapped into the plug wires. Be an interesting display at night for sure. 

[Steel cowboy]

Hey Grumpy instead of trying an LED how about a timing light hooked up to a difrent plug at a time. It would show the coil pulses for easy spark plug and because your using an induction connection the bike could still run. I used this method on my 72 SS nova and found a bad distributor cap.

[Grumpy]

Hey Grumpy instead of trying an LED how about a timing light hooked up to a difrent plug at a time. It would show the coil pulses for easy spark plug and because your using an induction connection the bike could still run. I used this method on my 72 SS nova and found a bad distributor cap.

Problem is 2 sensors, going into the cpu, which turns that into 3 pulses go through a circuit to fire 3 coils.  The valk fires 2 plugs at a time, 1 on tdc and the other on exhaust stroke.  Hard to figure out which pulse generator is flakey at the plugs. Also each pulse generator counts 11 pulses per revolution, total of 22 pulses going into the cpu.

[Steel cowboy]

I got you now Grumpy. I was just looking to find a way to see if the spark plug was firing or not. Thanks for that info on the pulse generators job.

[Grumpy]

Took it out this eve for a short ride, about 30 miles.  Cripes it hauls butt now, feels like it has picked up a few ponies. I changed the trigger wheel offset about 3 degrees while I was replacing the pulse generators, also a little work on the intakes.  I think the pulse gen's have been flaky for a while, just not enough to cause cylinders to drop out.  Roll on power is awesome now.

[Thunderbolt]

RP Brown is a very talented guy.  He is the one that put all the time and effort into the schematics that I use when I want something that you can read easily.  http://www.rattlebars.com/valkfaq/schematics/   In Maggie Valley quite a few years ago he demonstrated his circuit that read the pulses from the ECM and lit an LED over each cylinder as it fired.  Of course when the engine was revved up it was just a blur but at idle it was really impressive.  Doesn't exactly fit this situation I know but it just reminded of what he had done.  I remember JeffK having trouble with his in the past and like Grumpy had to have specialized test equipment to read the peak voltage of the pulse generators.

[_Sheffjs_]

Now I really want to know what these P Gs cost. If it is not that much it is better to play parts changer here? 

[Grumpy]

Now I really want to know what these P Gs cost. If it is not that much it is better to play parts changer here? 

$75.14 for the pair.

[_Sheffjs_]

Now I really want to know what these P Gs cost. If it is not that much it is better to play parts changer here? 

$75.14 for the pair.

Ok not great but not bad.  I wonder if we will see more of this simply due to age.   Interesting these flux  capacitors thingies.

[Grumpy]

Mine could have been shock or impact related. That is the motor out of the intestate , that bounced end over end for a hundred or so feet. Most of the covers were fractured, valve covers and front cover had a lot of damage.

[OLDFRT]

Bill, I am glad that you were able to find the problem. I had no doubt that it would be just a matter of time. Glad to hear that you are able to ride again, also.