The little gadget saved the day, read how below. (Image/OnAllCylinders – Paul Sakalas)

It all started with a few black spots under our motorcycle’s kickstand, directly above the drive sprocket—a sure sign of a weeping oil seal somewhere. Removing the sprocket cover revealed the drip was coming from the neutral switch.

No biggie: the seal’s cheap and you just pop the switch off, replace the seal, and reinstall the switch. Easy-peasy.

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<Narrator voice> Except it wasn’t easy-peasy. </Narrator voice>

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Phillips Head Fasteners v. JIS Fasteners

Editor’s note: This section has been edited to highlight the difference between Phillips and JIS fasteners.

As we looked closer, we noticed that the switch assembly wasn’t secured with the same Allen-head fasteners that were used elsewhere. While these fasteners looked like traditional Phillips head machine screws, they’re actually Japanese Industrial Standard (JIS) fasteners, which feature a different profile than traditional Phillips heads.

JIS screws demand a slightly different bit profile than a typical Phillips head. We used these Vessel bits, but plenty of other tool manufacturers offer them. (Image/OnAllCylinders – Paul Sakalas)

And after 20+ years of corrosion, heat cycling, and gunk buildup, the fasteners didn’t want to budge. Anyone who’s ever faced this situation knows that applying too much torque to fasteners like these will cause the head to strip, which would mean that you have to roll the dice on a screw extractor tool or, worse yet, the entire screw has to be drilled out. Stripping a fastener head is alarmingly easy to do, and it’s not a fun road to travel.

But! There was a solution in our toolbox: a manual impact driver.

Here are the two fasteners holding the neutral switch in place. (Image/OnAllCylinders – Paul Sakalas)

The Manual Impact Driver to the Rescue!

The manual impact driver is a handy gadget that’s worth its weight in gold in these situations. It comes with an assortment of bits and can shock a stubborn fastener loose.

Its operation is brutally simple: You stick the appropriate bit in the tool head, seat the driver on the fastener, and then whack the tool a few times with your hammer.

…Just make sure it’s set to lefty-loosey first by rotating the drive tool head to the proper marks (L or R, usually stamped near the collar).

All you do is position the impact driver on the fastener head and give the other end a few solid whacks with a mallet or hammer. Just make sure it’s set for lefty-loosey. (Image/OnAllCylinders – Paul Sakalas)

The driver will take that force and use it to turn the tool head slightly, we’re talking like 1/10th of a turn per whack. But that’s often all you need to get a fastener moving in the right…err….left direction. Better yet, the impact will also be transmitted through the tool into the fastener, just like an ordinary impact gun, to shock the fastener loose in the process.

A few raps with our hammer was all we needed to get both fasteners moving enough to where we could put a traditional screwdriver on them to finish the job.

As an unintended benefit, the tool’s bit may become lodged in the fastener head too. In these scenarios, if the fastener still refuses to budge, you can slip a box-end wrench around the bit (sizes vary depending on the tool) and use that as leverage to free the fastener.

A Few Words of Caution on Using a Manual Impact Driver

Look, we totally understand the frustration that comes from dealing with a stubborn fastener—but resist the temptation to use the impact driver as an impromptu therapy session.

In other words, be careful with that hammer!

For our Honda, we were mindful of its aluminum transmission case, along with the nearby location of the sprocket and splined transmission input shaft. One errant hammer blow could quickly make a bad situation worse.

We weren’t too worried about damaging the fastener (left) because we planned to replace them with Allen head fasteners (right) anyway. (Image/OnAllCylinders – Paul Sakalas)

One other thing to remember: You may damage the fastener head during the removal process, so have replacement bolts handy. But hey, replacing a few fasteners is way, way easier than drilling out a seized one. And it may even be a smarter move to replace the JIS screws with hex or Allen head fasteners anyway.

Cheap Insurance Against a Bad Day

The best part about manual impact drivers is they aren’t that expensive. And there’s no other tool that can really replicate what it does. Besides, after just one pesky fastener removal like the one on our Honda, you’ll easily see its value.

The manual impact driver is the perfect example of one of those unsung hero tools that you buy and toss in your toolbox, so it’s there when you need it to save the day.

We applied a liberal slathering of anti-seize thread lubricant to ensure our new fasteners wouldn’t suffer a similar fate. (Image/OnAllCylinders – Paul Sakalas)
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Author: Paul Sakalas

Paul is the editor of OnAllCylinders. When he's not writing, you'll probably find him fixing oil leaks in a Jeep CJ-5 or watching a 1972 Corvette overheat. An avid motorcyclist, he spends the rest of his time synchronizing carburetors and cleaning chain lube off his left pant leg.