That Which does not Kill Us... (Sportster Content)

[Jeff Higgins]

... makes us stronger...

Dang it, another breakdown on the old Sporty. This time ignition related. I've been running an electronic pickup "points replacement" type system that retains the stock mechanical advance mechanism (similar to the popular Pertonix units we run in our older points fired distributors). Well, the advance mechanism has two known points of failure, which usually happen together. The only question is which one fails first, thereby causing the other.

Here is the advance mechanism, your typical flyweights and springs, along with a good retention screw and a failed, sheared off retention screw. You can see how light and inadequate that screw appears:



Here is the back side of the flyweight mechanism. If you look real close, you can see just a little nubbin of a roll pin peeking through one side of the bore. This engages a slot machined into the end of the forward cylinder intake camshaft, and drives the flyweight mechanism. It is also apparent, under the most cursory inspection, that this stupid little nubbin is probably inadequate to drive the flyweight mechanism and absorb its acceleration/deceleration loads:



I think the roll pin probably shears first, which leads to the advance mechanism slipping on the shaft, which loosens the skinny little screw, which lets the whole works wobble, which breaks off the screw at the threads as shown. Regardless, I have now fixed this for the last time. Yes, when it failed, I had spares in my tool kit. There was, obviously, a reason I carry them. This was the third time in my 43 short years of ownership this has happened. Enough is enough.

So, I bought a full-up, fully programmable, pointless and flyweight less electronic kit known as an "Ultima":



The little cad plated cup is the trigger wheel, replacing the entire advance mechanism. This kit is a "single fire" setup, instead of the "dual fire", or "wasted spark" of the original ignition. It has a new split coil, the programmable "brains", and everything else needed.

All I can say, after installing this unit, is "holy smokes". It's a whole different bike. I had previously this year upgraded to a Pingle high flow petcock. Their motto is "don't let your petcock act as you your main jet". I think that is exactly what was happening with my original stock petcock - its flow was inadequate under full throttle. Between these two upgrades, the bike has simply taken on an entirely new personality. It has never run so well. Noticeably more power, better throttle response, much better idle, just everything is better.

I've normally been, admittedly, somewhat jaded regarding modern "upgrades" to vintage machines. Granted, the petcock doesn't qualify as such, but I have also replaced the old Bosch points type voltage regulator with a modern electronic unit. I now have to concede that these specific upgrades have made this old bike a much more "usable", and certainly more reliable machine. I've now drug her kicking and screaming into... the 1980's. And she's a better bike for it.

Funny how a couple of breakdowns and roadside repairs worked out.

[oldE]

Jeff,
Are you trying to tell us the ol' Sporty is not only going to be coming off the corners harder, but will be quicker getting to speed? The young fellas on their crotch rockets will not believe the old dude disappearing into the distance!
Well done! Welcome to the late 20th Century.

Best
Les

[Chocaholic]

Just curious. How did you narrow it down to the ignition? My Achilles heel in these scenarios is a build-up of frustration combined with an inability to logically narrow down the culprit (where to start).

Anyway…glad you were able to sort it out and improve your bike in the process. Very rewarding!

[flatbutt]

The adage "for those who get it no explanation is needed for those who don't , well no explanation is possible" is so very true.

I'm struggling with a clutch issue right now.

[Chocaholic]

Originally Posted by flatbutt

The adage "for those who get it no explanation is needed for those who don't , well no explanation is possible" is so very true.

I'm struggling with a clutch issue right now.

Or, I’ve heard it said: “If I have to explain, you wouldn’t understand”.

It very much applies to me. Took years of guitar lessons when younger. Can play scales and nearly every chord possible but can’t produce anything musical to save my life. Golf? Not a chance. Mysterious breakdowns by the side of the road? Fuggetaboutit.

Such is life.

[Jeff Higgins]

I hear you on the guitar lessons, Mike. My youngest son bought me one when I retired, saying "dad, you have all this time on your hands..." Just an exercise in frustration for me.

Roadside troubleshooting, though, makes sense to me. I follow a very simple, logical progression. I first think back to how it was behaving when it quit.

Was it like someone just turned off the ignition, just a clean stop, no weird noises, no sputtering? Then something equivalent to turning the key just happened. Gotta be ignition.

Did it pop and bang through the exhaust? Big backfires? Well, it had to be getting fuel to do that. Some cylinders were not lighting their charge, pumping it into the muffler instead. The lit charges coming from the good cylinders then lit those in the muffler. Intermittent ignition failure of some kind.

Did it buck and stall, then accelerate, without popping and banging? All available charges were getting lit, since nothing went off in the muffler. It's just that some cylinders were not getting a charge to light. Running out of gas, essentially, so fuel delivery related.

So, from the symptoms, we can often make an educated guess on whether it is ignition or fuel. From there, we "start simple and work towards complicated". Is there gas in the tank? Is it getting to the induction system? Do we have spark? Stuff like that.

Depending on which it is (fuel or spark) we start looking. Did a wire come loose? Did a hose come loose? Is a hose plugged? Is something obviously broken?

In this case, it let out a couple of tremendous backfires and died. Obviously plenty of fuel. Something worked, then didn't, then briefly did again in the ignition. From there, past experience indicated that if I removed the timing cover (just two screws), I might see something. And I did.

So, yeah, just a methodical, step by step, starting with easy things approach. It helps if the machine is "stone axe simple", like this old bike. Modern machines are much more difficult. Mysterious "black boxes" with two hundred wires disappearing into and emerging from them defy this approach. This is one of the beauties of the old stuff, though.

[Chocaholic]

You nailed it with the modern stuff. I start thinking about sensors, canbus, ECU’s and a myriad of other things I don’t understand. And eventually I’ll discover that my fuel gauge stopped working and I’m out of gas. But only after hours of aggravation.

[Jeff Higgins]

File this one under "I would rather be lucky than good"...

It turns out that the ignition module is programmed for three dead revolutions on startup. It's a trick used to keep them from kicking back and tearing up the starter sprague. Well, that obviously will not work on a kick started bike. I had no idea they did this. Neither did the the guy who recommended the part number I should order.

Luckily, as it turned out, even though neither of us knew about this situation, the part number he had was for a kit that included a unit specifically for kick start bikes, with the dead revolution feature programmed out of it. Whew...

Ultima is not entirely clear about any of this. A third party asked if we had the right part number for the kit, and went on to explain the situation. I actually had to go to an eBay vendor to get an explanation for all of this, rather than Ultima themselves.

I wonder how many guys just wind up pretty darn frustrated, and how many never figure out why.

[Por_sha911]

That Which does not Kill Us...
Will cost a ton more money!

[oldE]

Jeff, you were SO lucky getting the right kit for the old Sporty. I have often said I would rather be lucky than good. Some of the things that have worked out for me: I could never have been that good.

Enjoy
Les