Pazon Surefire revisited...

Yes, I am sure. The coils are stamped Lucas 17M12 as opposed to the 17M6. But previous owners of this Commando have made numerous modifications, ranging from primary belt drive, 18" wheels, a DYI wiring harness, which a plan to substitute with something that works, and lots of other small mods, so why not the coils. Maybe they just happened to be lying around. I don't see the point either, it would make the bike vulnerable to a weak battery.

OK, 6v coils bought and fitted, and I now have constant sparks on both plugs. This has resulted in very occassional firing on one cylinder only. So I'm now considering the old saying that 90% of all perceived ignition problems are carb related and vice versa. The bike is fitted with an SU carburettor, and although it has worked flawlessly up till now, maybe the winter lay up hasn't done it any good. Think maybe I'll just lift the bell and check the piston/slide' free movement. Will tell how it goes.

Hi Mike,Spot on, one HIF6 fitted. And correct also about the behaviour of both pots. I have to add though, that the occasional firing of the right cylinder has been very erratic, like 2-3 times through a 200 yards push! (yeah, that got the pulse right up where it shouldn't be too long!). I repeated the ignition test during the evening, after sundown, just to spot any sparks jumping where they shouldn't, and they didn't. On the contrary very clear and regular sparks from both plugs, so I'll have a look under the dome of the SU to se if the vacuum piston moves freely. I already checked the float bowl, which filled up with petrol alright, so I'm down to a very few things left to try.

The problem with all this is that I don't know which problem came first. Just before I laid the bike up for winter, it started cutting out. Rather than fix the old mechanical ignitionI decided to go for the Pazon. I fitted it without problems, and got sparks on both plugs, but didn't get around to actually starting or running the bike. Then a couple of months ago I rolled it out of the garage, fresh petrol and oil, but no go! Meanwhile I got sidetracked by another incident where an exhaust valve on my Matchless had a rendez-vous with the piston, which I then concentrated on. So here I am, not knowing what started it all, but I'm sure I have overlooked something fairly obvious, may be its time for a Malt and sit down and just let it come to me....I really miss the grunt and flexibility of my Commando!

I'll continue experimenting. I am sure the plugs fire at the right time. I have checked this over and over, even with the valve covers off, to be sure that I was on the compression stroke. The very occassional firing happened only on the right cylinder. Now, the spooky thing is that one plug came out wet, the other dry!!! I thought that the occasional firing caused that, maybe not? Perhapsit has something to do with fitting the points cover, because I did my checks without it. Another point on the list of things to try. The only that parts that haven't been changed is the Pazon unit itself and the wiring harness. But the latter I have ruled out, because I ran cables directly from the battery to the Pazon controlbox, thereby eliminating any possible errors here. I'm really at a loss here! Will report back when the revised checklist has been completed (just to please the Norton God I have relocated the Matchless to another shed, I'll see tomorrow if it has worked ) Thanks for your ideas!

... as a sidenote the Pazon fires both cylinders at the same time, so if one cylinder fires, the other should too. Apart from that it also fires a wasted spark on the exhaust stroke.

Previously neil_wyatt wrote:

Tom, are you using the specified spark plugs, Champion, hope so and E0 fuel (With no Ethanol added) That should eliminate those issues, as long as your fuel is getting through.

Hi Neil, you've got a point there, I am not using standard plugs. I use NGK platinum electrode plugs, without any built in resistance, so I don't see how that could affect thePazon. But nevertheless I am desperate, so will try to switch to standard plugs.

I suddenly stumbled over a post in a forum somewhere, where a guy was struggling like I am, until he finally, out of desparation, switched the two incoming wires from the controlbox to the trigger unit. Bingo, it started first kick. Somehow Pazon had got it wrong, so I'll try that as well.

Can anyone confirm that the Commando cams run counter clockwise? This is what Pazon says, andwhatI have used for fitting and adjustment.

I read somewhere, maybe even in the Pazon fitting instructions, that suppressed caps are not are a requirement, but fully useable. At the moment non-suppressed caps are fitted .

At the moment I am checking thecarburettor (SU) and fuel flow. First fault discovered was the SU bell contaminated with oil and dirt, probably from me overfilling the damper. This way the slide and needle was not able to move freely according to the vacuum created in the bell. Secondly I discovered a damaged thread on one of the bolts securing the carb to the manifold. It barely holds itself by the remains of the thread, so a possible air leak around this area.

One good thing will come out of all this, and that will bea number of small issues, both in the fuel and ignition system getting sorted along the way. Tomorrow will be my first attempt, after correcting all fuel related problems, to once again start the beast. Hopefully I will be rewarded with more than just the occasional baark from one cylinder!!!

Previously tom_mortensen wrote:

I have read up on many old posts to try and find an answer, but to no avail.

My 1972 750 Commando runs a Pazon Surefire ignition, or rather it should do! Everything is fitted according to manual, and the plugs give a weak spark outside the cylinders, and during the Pazon selftest,but none inside = no go! I have checked all connections 3 times, and everything is to spec, except the coils which are 12V. Pazon recommend using 6V coils, but state that 12Vcan be used if total resistance measured over the coils, secondary windings,connected in series, is not over approx. 4 ohms. This is where it gets tricky, because my 2 x 12V coils measure about twice as much, approx 7-8ohms !

Has anybody got any experience whether this would prevent the Pazon from performing? I intend to try new coils anyway, because it is my last resort. But it would be nice to know if anybody could confirm my suspicion?

Ok, first of all thanks for all your suggestions. They inspired my to check the whole setup once again. I found no faults in the Pazon setup or wiring. I did though run a separate earth wire back to the battery. But still no starting, though the occasional firing on one cylinder improved from occasional to every yard of pushing!!! Thought about dropping my gym membership, but instead I reverted to my thoughts about fuel supply. So the SU was cleaned, with the problem areas mentioned, fresh supply of fuel in the tank, but by now the wet sumping problem reared its ugly head, as half of the oil tank's contents had found its way to the sump.

Nevertheless, I put that aside, after all this has happened many times in the past, when it only took a few minutes of running to return oil to the tank. So I switched on the ignition, applied the choke, and kicket it once, wearing my soft gym shoes. What a kickback! I'm in busines, I thought, as I changed into my boots. Another kick, and she rumbled into life in a cloud of smoke. A few minutes of warming up, and off I went, and we're back in business. Lots of torque, great pick up, everything sorted. All I need now is to strobe the timing, and check the advance, but it felt as pretty much spot on, so I guess this "minor" problem is out of the way!

Well, what can I cay? The 10/90 percent rule, kicked in once again, a perceived ignition problem, turned out to be fuel related. Thanks for your patience!