Pamco ignition

[Bigred]

Hi I am new a few years ago (5) I bought a Pamco ultimate set (includes coils) I have installed it in a 71 I am building
The plugs keep fouling checked all the proper things in the carbs and timing and the voltage at the system.I am using Nick d8ea plugs
they are new but keep fouling when trying to start cold
thanks in advance for any help
Jim

 

[amc49]

Compression check to make sure nothing out of line with the motor.

I don't like those as you cannot really set the individual sensors separately, only both at same time. As well you cannot set air gap which is often critical with getting a good hard pulse to trigger your rest of ignition. At least from what I can see. The instructions don't seem to provide for it.

A less than stellar battery can do it too.

 

[Bigred]

I rebuilt the engine to a 815cc But I have ordered an adapter to check compression (14mm- 12mm) The battery is new but the voltage seams a bit low at cranking it drops about 2 volts When I get the bike to run it runs good the timing is to max advance at 2500 rpm on both sets of cylinders When I turn the key on then off I get a spark and sometimes a back fire Would the NGJ d7ea help the start up or maybe stock coils I have a market complete system on the shelf I should just change it out
Thanks
Jim

 

[amc49]

Well the 7's may help but they are supposed to be too hot. Engine accepting them would be hinting at missing compression or weak ignition. What about valve sealing?

What kind of dome on your pistons, any at all? Are the carbs stock with OEM jetting numbers? What are the idle air screws set at? What plug gap? Wider forces coils to output more spark, at least until they can no longer do it. OEM is around .024"-.028".

 

[Bigred]

When I did the engine I had the head done The pistons are pretty flat In the morning I will pull the float bowls and check the jets I don't remember what jets I put in I have got the plugs set at .035 I know it a bit wide but I was hoping for a hotter spark The idle screws are all the way in I am with you about the size of the wires I will try a wire to battery ground in the morning
Thanks
Jim

 

[amc49]

Not impressed with that pitiful looking unit at all after looking at it on the net. You may want to run a dedicated ground from the unit (black wires) directly to negative battery post to check for issues. The red and green wires are so small I have an issue with them carrying enough power to really power a good ignition whack out of the coils. At least the greens since they are supposed to instantly ground the coils and the quicker (bigger wire does that) the hotter the spark generated. Kinda worthless to brag about the speed of IGBTs when the small wire slows the unit discharging down.

Instructions seem to say run at least resistor plug or wires, the unit may need that to make good spark.

Use kill switch more and cut engine off with it, turn key on and whirl starter to then pop kill switch on a fractional second later to start engine and the backfire issue stopped. A change in technique maybe.

I've used hall effect switchers that work like gangbusters before but they were separately adjustable and so you can really zero in on nominal air gap, that makes them switch much cleaner and the logic pulse then has less noise in it. I used GM car HEI units on my DOHC for instance, they fired a .060" plug gap all day long. Not Hall effect those, rather it used the simple OEM Honda magnetic impulse pickups. On that bike the ignition fired so hot the carbs had to be jetted up, the stock electronic ignition was that weak.

 

[dirtdigger]

I was never fond of the Pamco units either but they have been on the market for many years and have proved to be very reliable. If you having running issues it is more often then not something else beside the Pamco.

If your idle screws are all the way in then you have issues elsewhere not the ignition.

 

[madmtnmotors]

If your idle screws are all the way in then you have issues elsewhere not the ignition.

+1

If the bike runs and you are getting good spark, then you need to consider looking at the fuel delivery. A properly tuned bike should not idle at all with the idle screws turned all the way in. Working on carbs sucks, and denial ain't just a river in Egypt. I once swapped engines because of a poor running condition since I did not want to open up the carbs yet again. The donor engine, with the same carbs, ran exactly like the one I pulled out. At that point I had to overcome my denial and was resigned to addressing the carbs. The fact that the idle screws are turned all the way in, yet you are still experiencing an overly rich condition, leads to several possibilities:

>Vacuum leaks
>Float heights
>Jet sizes
>Idle stop screw set too high
>Loose/broken/sticking carb components
>Any combination of the above

If you have a stock ignition, then by all means install it just to rule out any issues with the aftermarket ignition. The idea is not to change too many things at once until you have resolved the problem, or you will never know what the problem was. Worse yet, by making too many changes at once, you can inadvertently fix the original problem, yet "break" something else that exhibits the exact same symptoms!

I hate it when that happens...

 

[amc49]

+2

That is NOT correct on the idle screws, the engine should be dying like that.

Uh, if still using the OEM Keihins then I'm thinking the idle airscrew IS the issue, they are air only on that one being located between carb slide and airbox rather than forward. Meaning closed will be rich as hell at idle. Need to be open like 1 turn and go from there.

Feel free to correct me..............

Any decent ignition should fire a .035" gap but that's all I could get out of the vaunted Accel coils I used to run. Why I went looking for something else.

 

[amc49]

I probably misspoke somewhat above, the green wire size doesn't matter so much when the ground lead is opened, rather you want the wires supplying coil both in and out as big as possible to saturate it quicker, it lowers the required dwell time.

 

[Bigred]

when you set or balance the carbs the first thing you need to do is turn in the idle screws.I never they do much in or out .But I am having this problem so its worth a try I am abit concerned that I may have made the problem .Back in the day we would have the slides machined that is to remove about 008 from the boottom it would sweeten up the sppt from idle to main jets .I had this done.I did not work on this bike today other things got in the way
jim

 

[madmtnmotors]

Closed will be rich as hell at idle. Need to be open like 1 turn and go from there.

I forgot the early carbs are air screws. Turned all the way in would indeed contribute to an overly rich condition.

My K8 idle mixture screws are just the opposite and are actually fuel metering screws.

 

[Dave]

I love my pamco. Set it and forget it. My bike was already running good when I installed it. You never mentioned the plug caps though, if bad they can kill the spark too.

The pamco is very basic and I didn't care for the wiring either so I changed it but I haven't had any reason to even look at it since I installed it.

 

[Bigred]

New plug caps came in the kit they are NGKs I believe they are resistored
jim

 

[Bigred]

I want to thank all who have responded to my request for help.This bike is going in thr conner for a bit I have too many others to work on
thanks all
jim

 

[amc49]

For sure something is wrong with carbs if the airscrews have no effect, it generally signals clogged passages.

You NEVER turn any air or idle screw ALL the way in, that is a mistake, it produces the same effect as the clogged passages. You start off at like 1-1 1/2 turns open. I use 1.

I used to cut slides myself on Dad's mill. Varying amounts depending on need, you can also drill air bleeds to do the same. Or lower the choke on the needle jet if it has one.