Part I: Spark Plug Basics

Maintenance and Set Up Tips

Replacing of plugs really should be almost as easy as changing light bulbs, however it's not. Bulb replacement does not involve the use of a socket wrench or gapping utilities. A deep socket that fits a plug isn't a suitable spark plug socket. A plug socket has a couple of things that separate it from a deep socket.

The first is a foam rubber insert that pads the spark plug while it is in the socket. Second is the hexagonal part around the top socket. The hexagonal area provides the wrench to set on the socket if there is insufficient space for the ratchet. Motorcycles usually have plenty of space for ratchets and torque wrenches, but the ability to accommodate a wrench on the socket comes in handy for motorcycles with Fat Bob tanks as well as some automotive applications (like a Corvette with headers).

For several years there have been two standard types of plug sockets. 80" Big Twin Evolution and Shovelhead engines require a 3/4" spark plug socket, and Evo Sportsters and Twin Cams need a 5/8" one. And then something took place: spark plugs that required an 11/16" socket came out on the shelves, and 11/16” spark plug sockets are sometimes hard to find. I've seen people fit a short length of foam pipe wrap (the one used commonly in hot water pipes) inside of an 11/16” deep socket to make their own. This procedure is effective and is also an inexpensive solution to improvise an instrument for the person who doesn't replace a lot of 11/16” spark plugs.

Plug Spacing

Spark plug spacing is crucial for accurate firing. Many people assume plugs are already gapped from the factory, which isn't usually correct. Though even if plugs are already gapped, movement when shipped may make the spacing quite a few thousandths inches shorter. Spacing a spark plug isn't rocket science. All it takes are the appropriate tools, some practice, and a little bit of determination.

For starters, pliers and a feeler gauge are not the right tools. Our preferred gapper is the simple, good-old wire-loop tool where every wire loop stands for a distinct size of the gap, and also the metal tabs support a variety of ground electrodes. Our very least favorite may be the disc which has the ramp around the perimeter. The first issue with the disc style is that it puts strain on the center electrode while gapping. Another problem is that one part of the ground electrode might end up somewhat farther out from the center electrode. Screamin' Edge and SplitFire spark plugs, one prong of the ground electrode can be higher than other plugs.

Focusing on 3 straightforward procedures will allow you to correctly gap plugs. Initially, don't try to bend the center electrode. Second, never bend the ground electrode laterally. Utilize the spacing tool to slowly push the tip of the ground electrode near or farther from the tip of the center electrode. Additionally, check the gap by working out the correct wire loop in between the gap. The spacing is right when you feel a slight amount of friction when the wire moves in the gap.

Changing Spark Plugs

Just before the removal of a plug, wait until the engine has cooled down, and then start using a shot of compressed air to clear out dust and dirt away from the space around the spark plug. A ratchet and a spark plug socket are my desired utilities for this section of the process. Upon cautiously taking off the spark plug wire by pulling on the boot, not the wire, I remove the aged plug with a ratchet and plug socket by turning them counter-clockwise.

When the worn out plugs are finally out, it is time to mount the correctly spaced plugs. Start out by putting a tiny amount of lubricant on the threads for each plug. Current Harleys have aluminum heads and spark plugs have a steel shell. Repeated heating and cooling of the cylinder heads may cause a chemical reaction from the steel spark plug shell and the aluminum cylinder head. This results in an effect like it has been welded.

Soon after applying the lubricant oil around the spark plug threads, begin winding the spark plug clockwise into the head working it with your fingers rather than a ratchet and plug socket. A best practice that lowers the possibility of getting a cross threaded plug and the costly damages that may occur.
After the brand new spark plug is finger-tight, reach for the torque wrench and spark plug socket. The torque spec for spark plugs in a TC 88 is 11-18 ft-lbs., so split the difference and go for 15 ft-lbs.

By doing this, if the torque wrench turns out to be off with no reason in mind, you will still be within the recommended spec. Is the right torque critical for spark plug installation? Typically, indeed yes! If the spark plug is too loose, heat exchange to the head may be reduced, while the plug may overheat. If a spark plug remains not tight enough, it possibly can work its way out from the head due to vibration and combustion pressure. And that is very harmful. Insufficiently tightened spark plugs are also held responsible for combustion chamber debris finding their way into the threads of the spark plug hole.

On the other part, turning plugs too tight can cause other problems. If a spark plug is tightened too much, the chances are it'll be harder to take out. Over tightening may also crush the gasket on the gasket seat plug. Over tightening can harm the threads in the head and has been the suspect in the gap distorting.

Without having a torque wrench, get the fresh plug tightened using the finger and utilize a ratchet to carefully tighten the plug another quarter to half a turn. This approach is certainly a lot less accurate as compared to utilizing a torque wrench, but it can get you somewhere in the 11-18 ft-lbs. limit.

This season, bike runs are going to kick off all throughout the US. The vast majority of motorcyclists will undoubtedly be congregate for one week long festivity all expressing their love for bikes. You will hear a number of stories and building tips to chat about with brand new friends while you ride the time in the rally. Be sure to ride safe and put on the necessary safety equipment like carbon fiber helmets. Best of luck and have a wonderful ride.

Restoring a World War II Bike Relic

So many wonderful stories have been told over the decades, chronicling the elusive “barn find” appears impossible that any more could exist. Time has shown us a lot of lessons and none are prevalent than the fact that old stories are retold. Certainly, given plenty of time, it's possible, but the story around this ‘42 Harley-Davidson WLC seems to be a one time episode. A genuine barn find makes for a great tale, but a Second World War Harley adorned in Honda parts and stashed inside a barn in a rural region in England? Well that would be an interesting story. 

Custom builder Nick Gale said, “I found it whilst visiting a relative A decade ago. I got to talk to a local farmer whilst strolling my dog one night and he mentioned he has an oldtime motorbike his father had purchased in 1945 from a soldier at the conclusion of World War II. The farmer told me he knows it was a Harley Davidson, and I could buy it if I wanted to. The motorcycle had stayed in his barn from 1945 until 1981 he made a decision to make use of it and get it running.”

Looking over the bike, it had 18-inch front and rear wheels from Honda, a vintage Honda gas tank, Honda fenders, a Suzuki headlight, handlebars from an lronhead Sportster, a hand clutch, and a bigVincent sprung saddle. The farmer had painted the entire motorcycle yellow, as well as all the nuts and bolts. Nick goes on to say that the bike had a long-expired UK registration and after checking the engine, forks, and frame ensuring they were complete, he made the deal for about $1,200.

Nick adds, “When I got it back home, I got the motorcycle working and was thrilled to see there were no crackling sounds, no smoke, and like every '42s, once on the streets, there are no breaks.”

To prep the Harley Davidson for its resurrection, it was stripped down to the basics. New 16-inch tires were purchased to exchange the Honda tires and the very first snafu was encountered. Running the front rim with the springer forks was pretty simple, but the farmer had heated and bentthe back of the WLC's body to make room for the Honda wheel to fit. With most of his friends telling him its junk, Nick opted to keep up the classic frame and just get a little creative with the rest of the bike.

Nick adds, "The drop seat concept happened when we cut the back off. We used most of the original pipe work and chose to form the backbone too. And the frame was created. The hardest part  was having the seat plunger to enable us to use a new seat reduced by  a few inches from stock. It required 4 hours with a hammer to get rid of the existing seat post that was welded in." From  this point the tale goes stagnant. After acquiring the motorcycle in 2001 and getting the bodyremolded, "biker wants" have prevailed and the old Harley Davidson was boxed up and shelved for yet another day. That day didn't come for the next decade. In early 2011 the bins were made available and readied for restoration yet again.

Opening the 45-inch motor uncovered another amazing discovery. To Nick's enjoyment, the interiorwas like new and with the crank split, the World War II oil spilled out. Checking closely unveiledcompletely unmarked interiors with matching numbers. After putting the complete stock 750 cc flathead together again, the Amal carburetor was refurbished and topped with a brass velocity stack. engine received brass accents over fresh paint job and all oil and fuel lines were created with manually bent copper tubing. The bike came with a worn out and dirty clamshell exhaust. To cover up decades of punishment, the pipes were wrapped to disguise the blemishes and a bend enablesthe pipe to boast a little for more style.

Nick said, “The gears are modified by a smaller sized shifter we produced which still runs the mouse trap clutch. All braking systems and clutch systems are authentic as are all the switch gear, levers, and cables. All the parts were acquired as original or refurbished stock wich would likely be very close as Harley Davidson would've done 70 years ago. The motorcycle ignites on the first or second kick and even the hill brake is working, well, sort of.”

Bodywork was not overdone and carries a classic overall look, but that is where resemblances stop.  The back fender began life as a winning piece that was modified with a customized set of struts and backed with a back light. Adding some across-the-pond design, the registration tag is meant to seem like a 1940s English pub sign. What would you expect from any English motorcycle builder? Peeking deep into the gas tank, it becomes clear work was done.

Nick designed and made the unit into two parts that interlock just as the original but with added style and a bend more in line with the framework changes. The seat rocks off from the framebrackets to a spring inside the old seat post tube. All the rest of the components are genuine '42 Harley WLC or new old stock. A classic black paint was applied to all the exposed metals with gold highlights painstakingly painted by hand. One last thing is a vintage motorcycle helmet to completethe WW II look of the bike.

Just in two days of its 6 week transformation, the '42 WLC was exhibited at the South of England Rally and came home with its very first award as winner of the Best Professional Category. Two weeks later it made an appearance and won Best Classic at the annual Bulldog Custom Show. After sitting in boxes for A decade, Nick clearly understood that if he didn’t took time to work with the Harley Davidson, it would be subject to another 10 years of sitting there. It started from an ordinary project into a labor of love. Nick concludes, "It's fun to drive a bike once you get used to it. I, for one, love it to death."