To use – or not to use – synthetic oil in engines made decades before synthetic oils were in common use . . . that’s the question!
And there are several answers.
I just discovered one such – I think – by stumbling into it (figuratively).
One of my old rigs is a 1983 Honda GL650 Interstate, which was – for one year – a kind of little brother to the same-year Honda Goldwing. It’s a curious Honda in that it is not powered by an inline (or flat) four but rather a slightly off-center – or “twisted” twin. It’s got a pushrod-actuated valvetrain and a 9,000 RPM redline, which is a pretty interesting combo just by itself.
Anyhow, I ride this bike a lot because of all my bikes, it’s the most practical. It has the full Goldwing fairing, so lots of wind/weather protection and lots of storage, which is helpful when you need to cart more than just you around. But it’s hard to ride when your bike won’t start – not because it needs a tune, but because the starter clutch seems to be failing.
That seemed to be happening beginning a few months ago, at the start of the riding season. I’d push the starter button and instead of the starter turning, a sickly whirring – the sound of the starter clutch slipping. This happens when the little springs inside the clutch either fail and break or fatigue such that they lose their former necessary tension and can no longer engage the clutch, which slips . . . enter the whirrs.
Now, these three little springs – new replacements – only cost about $15 for the kit. But to install them entails removing the engine from the bike. This is Step One. It is one of the few things about this ’83 Honda that hasn’t made me pat it on the tank. Huge hassle, especially when your garage is overflowing with other stuff and finding room – and time – to tear down a bike seems almost as challenging as explaining to a “masker” the illogic of him demanding others wear them if his “works” as he insists it does.
So I figured I was on borrowed time – and might as well make the most of what remained, by riding the bike until the starter clutch failed completely and starting the bike became an impossibility. Or at least, impracticable. Roll-starting is always possible with a bike – but that requires a hill to roll down. Or someone strong to push you from behind to get a rolling start. Or a kick starter, which this particular bike does not have.
I also figured I probably ought to change the oil and filter while I still can. Or rather, change it after the engine had been started and warmed up, which is preferable to changing it when the engine’s cold because the oil drains faster and the stuff you want out of the sump isn’t settled in the bottom of the sump and less likely to drain completely.
Well – and here’s the punchline to this story – I had been using synthetic oil in this 40-year-old Honda’s engine. But when I went to get a fresh jug at the bike store, they were out of my usual. So I got a jug of Honda-brand non-synthetic, thinking it’s fresh oil and that’s what matters most.
As it turned out, other things may have mattered more.
After having changed the oil – from synthetic to conventional – the starter clutch seemed to have heeeeeaaaaauuhld itself, Ernest Angley-style. When I pushed the button to start the bike, the starter turned – rather than slipped. No more whirrrrr!
The engine started.
It has done so without interruption since I reverted back to the kind of oil that was specified for this engine by Honda back in the early ’80s. Maybe the problem with the slipping starter clutch was due to the synthetic being more slippery than conventional oil. Maybe it had to do with the synthetic being a different (lighter) viscosity.
All I know – for certain – is that since I went back to the type (and weight) of oil that Honda put into this engine when it was new, 40 years ago, the slipping starter clutch problem – the only mechanical problem I have ever had with this 40-year-old bike that I have owned for more than 15 years – is no longer a problem. It appears the problem had been created by the use of too light/too slippery oil – and solved by not doing that anymore.
I’m grateful to the Motor Gods, at any rate – because I can ride the bike rather than pull the engine in order to replace three $15 springs!
. . .
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