I’ve been fixing things that aren’t broke.
It doesn’t take a great deal of imagination to anticipate how that’s been going.
Now maybe to describe these things as ‘aren’t broke’ is being charitable.
Maybe they ‘aren’t broke’, but they’re not working perfectly, either.
In the days before digital control of everything — where stuff either works or it doesn’t – I believe we used to refer to these efforts as ‘tuning’.
The whole notion that ‘works’ is a continuous analog sliding scale starting at “doesn’t work”, moving on through “works, but works really badly”, to “works OK, but could be better”, to “works pretty good, but isn’t perfect”, to the goal of “Angels Sing — Motor Nirvana” is an idea that has a tough time making the transition from analog to digital controls.
In this world, how my engine runs with .012 inches of spark plug point gap and 2 extra degrees of spark advance and how it runs with .014 inches and 4 extra degrees of advance is for me to evaluate and accept or deny. Maybe software developers deep within the bowels of Original equipment Manufacturers are looking at parameters like this on dyno runs, but if you own a modern motorcycle, and don’t own a copy of your manufacturer’s Engine Control Module Software Development Kit, these micro-adjustments are unknown to you — I might as well be asking you about the detailed processes required to select the next Pope.
If the perfect is truly the enemy of the good, then the perfect has been my hell-bent foe for these last two weeks while I tried to take an R90S that was running well and turn it into an R90S that made the angels sing.
The last time I replaced an ignition point set on this motorcycle was likely 1999. Because the bike is equipped with a Dyna Ignition Booster unit, the point sets only run at 5-12 volts instead of 15,000, so damage and erosion due to pitting is reduced to nearly nothing. Nearly nothing, it should be noted, is not absolutely nothing, and, over long periods of time, like, for example 15 years, both the cam rubbing blocks and the miniature axle of the point sets both wear until their function deteriorates so that it can finally be detected from the saddle.
Having delayed that inevitable as long as I could, I finally decided to set things right.
A lot, it seems, has changed since 1999.
The most significant change, in this context, is that Bosch has stopped making points for BMW motorcycles in their German factories.
I can understand why this has happened, when their target market has been reduced to, well, me, and maybe you, buddy.
Putting aside the possibility that maybe, given my bike’s lack of collector value, it might be time to hang it the hell up and convert it to an electronic ignition, I set about trying to locate an ignition point set that wasn’t entirely made of finest cheese. Besides, that upgrade line of inquiry is very dangerous ground, because once one begins to think that way, the logical conclusion ends up heading towards tossing the whole bike out and replacing it with a Kawasaki 650 Versys or Honda Africa Twin, either of which requires virtually no fettling and just needs being ridden.
Clearly a subject for another time.
Anyway, I located a reproduction point set from a vendor that over time has earned my trust. I disconnected the battery, popped off the front engine case, and gapped the new points.
After setting the gap at the recommended nominal .014 inches, I discovered that even with the points plate set at full ignition retard, the overall timing was still about 4 degrees advanced over specification.
This isn’t the first time I’ve seen this. The issue is that the points rubbing block that rides on the ignition cam is a few thousandths thicker than specifications, making adjustment to stock timing nearly impossible. As the rubbing block wears, though, the timing retards, so over time the timing will converge back to the desired value. So I set a slightly narrower point gap — which also retards the timing — buttoned the cases back up and went riding.
After 3 or 4 hundred miles of road time, the bike started to run badly, and on one trip, it felt like I barely made it back to the garage. As the bike quit at the top of the driveway I was pretty sure I could hear a faint squeak coming from the front of the engine.
I was pretty confident that I knew what I would find when I took the cover off this time.
Back when they made points, Bosch always provided a tiny capsule of specialty grease to apply to a felt pad that lubricates the ignition cam. Well, now that Bosch doesn’t make points, they don’t make the cam grease either.
I hoped that a felt with 41 years worth of grease worked into it would be close enough.
I hoped wrong.
I now, for your amusement, recommend that you go to the Internet and attempt to find some Ignition Point Cam Grease.
I’ll wait while you do that.
What’s you have no doubt found are several references to these products with “Out of Stock” messages.
The grease, unsurprisingly, is as endangered as the ignition points themselves.
A phone call to my local NAPA store — home to shadetree, pickup truck and dirt track car mechanics everywhere — yielded the fact that they have a long enough institutional memory to know what the blank I was talking about.
For anyone encountering this same issue, NAPA’s ML-1 moly lubricant – which isn’t available on their web site — is specially formulated for just this application. Those nice folks will sell you a 7 ounce tube which, by my calculations, should last me for the lifetime of about 120 BMW motorcycles. Which means that I have about 118 more motorcycle lifetimes than I will ever need.
If you come up short I’ll be glad to share mine.
Anyhoo, I asked the nice folks at NAPA to get a tube transferred in from their warehouse, and then I’d ride (a different motorcycle) over and pay them a visit.
While that was going on I spent some time in deep contemplation of spark plugs.
The spark plug in question was for Finn’s diminutive Buell Blast, which, if experience was any guide, likely still had the OEM Harley Davidson branded sparkplug threaded into its cylinder head that was placed there when it was built in 2002.
I went to NGK’s web site and found the recommended stock plug for the Blast. I don’t know whether this is true of the Sportster engine upon which it is based, but space must be at a premium in those cylinder heads. I would have fully expected the bike to use a 7/8th inch refugee plug from a Chevy 350, but instead found it used a diminutive 14mm miniature plug.
While I was mucking about in the NGK application finder, I checked the OEM plug for my S. What I discovered was that one day, many years ago, when I had walked into an auto parts shop to obtain some replacements for the Champion plugs I was using at the time, the counterman was out of stock on the Champions I used, and crossed them to an NGK number. That NGK number, it turned out, was actually one heat range colder than the recommended plug.
Net/net — for some time longer than a decade, I’d been using the ‘wrong’ plug in both my airheads. Now tuning being as much art as science, I’ll share that in my /5, the 7 heat range plug looks just fine when one takes a plug reading. In the R90S, though, with its accelerator pump carburetors, the plugs always look a little more carboned up than optimum, and now I understood why that was.
Turned out NGK also made a ‘tuners’ version of the plug, with a U shaped electrode and a grooved center, which I’ve found actually makes a better flame front in this engine. I’ve also tried their fine wire platinum plugs, which barely work at all and foul quite easily.
So I had the NAPA guys pull 8 of the proper plug for installation and spares when wrenching time came round.
After riding the LT over to the Brunswick NAPA on Saturday morning, I rolled the S to the sunlight in the mouth of the garage, disconnected the battery and pulled the front engine cover.
My powers of visualization had been correct. The points block had worn beyond rapidly, to the extent that they were barely opening on the cam.
Upon reflection, I don’t know how I had gotten home on that last trip out.
I regapped the points, massaged some ML-1 into the cam lube felt, and soaked a clean rag with some additional to pre-lube a thin film of the moly onto the advance unit’s cam surface. I checked the timing, which was still marginally overadvanced but closer to stock, buttoned up the front cover, and installed the new plugs.
If one believes Airhead Yoda Snowbum, the only proof of excessive spark advance is pinging under load, only the road would have the answer.
The road did have the answer, and the answer was the Heavenly Choir. Alternate US 40 headed up to Braddock Heights is an 11/10th mountain road, with a series of great switchbacks and sweepers going up a series of steep grades to the ridgeline at the top of Braddock Mountain.
Braddock Heights is likely the only memory of British Army General Edward Braddock, who used the ridgeline road to move his army, which included a young officer named George Washington, towards Ohio for an engagement during the French and Indian War. That engagement ended so badly that the troops needed to bury the General, who had been ambushed and targeted by a brigade of Indians and French scouts, in an unmarked grave in the middle of the road so that they could not be easily tracked in their hasty retreat. All things considered, it was a matter of some luck that the young Lieutenant Washington survived that campaign.
Going up to the Heights, the S was fully warmed up and in full song. Throttle response was instant — either at low revs or high. Pre-ignition tends to be a bigger problem in Airheads beneath the torque peak at lower revs, but low or high this was a happy engine.
My work here was done, and done well, Citizens.
At the top of Braddock, I turned left onto Jefferson Boulevard, with the intention of heading into the Valley and from there back home. As I turned onto Cherry Lane to drop back down the ridge and into The Valley, what I saw just took my breath away. I instinctively reached to the right handlebar, killswitched the bike and coasted into the grass.
I write all the time about The Valley. I ride there almost daily, and hope that my words paint a picture that people can carry with them. We’ll leave aside whether I am successful or not in that endeavour, because these images, grabbed on the fly with the cel phone in my pocket, paint a literal picture that goes at least one level beyond what your imagination can likely provide.
Below, with the sun setting on the Valley’s opposite ridge, was Jumbo’s Farm, one of the larger and more prosperous agricultural operations hereabouts. Knowing that my work had restored my precious motorcycle to full function is a full hearted feeling that is difficult to adequately describe — it’s an example of mind over material.
This view, though, was one of those Nature in Her Perfection illustrations. It doesn’t matter what faith you may or may not profess, but creation, whether at the top of a pass in Glacier National Park, or three miles from your garage, can still be absolutely awe-inspiring.
This bike, and her biker, were completely happy in this green and shining moment.