Motorcycle Spark Plug Basics

Motorcycle spark plug, new spark plugs
Motorcycle spark plug, new spark plugs—yoppy (

Check up and Install Tips

Replacing motorcycle spark plugs really should be easy, but it’s not. Changing a plug requires using a socket wrench or gapping utilities. An extended socket that fits a plug isn’t a correct plug socket. A spark plug socket has two things that differentiate it from a deep socket.

First is a foam rubber insert that pads the plug while it’s within the socket. The second is the hexagonal part around the top socket. The hexagonal section allows a wrench to set on the socket if there is insufficient room for a ratchet. Motorcycles generally have enough space for ratchets and torque wrenches, but the ability to support a wrench on the socket is useful for bikes with Fat Bob gas tanks and a few auto applications (like a Corvette having headers).

For many decades there were two standard types of plug sockets. Shovelheads and 80″ Big Twin Evolution engines need a 3/4″ spark plug socket, and Evo Sportsters and Twin Cams need a 5/8″ one. And then some thing occurred: spark plugs that required an 11/16″ socket where available on the market, and 11/16″ plug sockets are often difficult to find. We’ve heard individuals put a short length of foam pipe wrap (the product that’s often used to insulate hot water pipes) inside of an 11/16″ deep socket to use by their own. This method works and is an inexpensive solution to improvise a tool for the person that doesn’t replace a lot of 11/16″ plugs.

Spark Plug Spacing

Plug spacing is essential in getting accurate firing. A lot of people assume spark plugs are already gapped at the factory, which is not often true. And yet even when plugs are pre-gapped, activity when being shipped can make the space quite a few thousandths of an inch smaller. Spacing a plug is not too difficult. What in only needs is the ideal tools, quite a few practice, and a bit of dedication.

To begin with, feeler gauge and pliers usually are not the right tools. My favored spacing tool is a good, old wire-loop tool where every single wire loop stands for a different gap size, and also the metal tabs accommodate distinctive ground electrodes. Our least favorite is the disc with the ramp around the perimeter. One problem with the disc style is that it puts stress on the core electrode when gapping. The other issue tends to be that the other side of the ground electrode may end up a bit further out from the center electrode. Screamin’ Edge and SplitFire spark plugs, 1 prong of the ground electrode could be a bit higher than the other.

Focusing on 3 simple guidelines will allow you to properly gap spark plugs. Initially, don’t flex the center electrode. Next, never ever flex the ground electrode sideways. Use the gapping tool to slowly move the end of the ground electrode closer to or farther from the end of the core electrode. Finally, check out the correct spacing by moving the correct wire loop in between the gap. The gap is right once you feel a little amount of friction as the wire moves through the gap.

Replacing Spark Plugs

Before the removal of a spark plug hold off until the engine has cooled off, and then use a shot of pressurized air to clear out dust and dirt away from the area around the plug. A ratchet and a spark plug socket are my preferred tools for this particular section of the task. Upon diligently removing the spark plug wire by drawing on the boot, not the wire, we will take out the aged plug with a ratchet and plug socket by turning them counterclockwise.

When the old plugs are out, it is time to install the properly gapped plugs. Start out by applying a small amount of anti-seize lubricant on the threads of each spark plug. Current Harleys have aluminum heads and spark plugs have a steel shell. Repetitive cooling and heating of the cylinder heads may set off a chemical reaction from the aluminum cylinder head and steel plug shell. The result is a spark plug that acts like it’s welded in place.

Soon after applying the lubricant (anti-seize) around the spark plug threads, begin turning the spark plug tighten manner to the head using your fingers rather than using a spark plug socket or ratchet. A best practice that lessens the possibility of getting a spark plug that is cross threaded and the pricey damage that may occur. Once the brand new plug is finger tight, reach for the plug tools, the torque spec for plugs in a TC 88 is 11-18 ft-lbs., so split the main difference and opt for 15 ft-lbs.

That way, if the torque wrench is a bit off for some reason, you’ll still remain within the required spec. Is proper twisting vital for plug set up? Basically, yes! If the plug is too loose, heat transfer within the cylinder head can be lessened, and the spark plug can overheat. Whenever a plug remains really loose, it could find its way out from the head caused by combustion pressure and vibrations. And that’s very unhealthy. Plugs that are not tight enough also hold responsibility for combustion chamber debris showing up in the threads of the plug hole.

At the other extreme, turning plugs excessively tight will cause other problems. If a spark plug is over tightened, it’s likely that it’ll be tougher to remove. Over tightening may also grind the gasket within a seat plug. Extreme over tightening can damage the threads within the head and has always been the cause of deterioration.

Without having a torque wrench, make the fresh plug tightened using the finger and use a ratchet to gently tighten the plug an additional quarter to half a turn. This method is clearly less precise than using a torque wrench, nevertheless it can get you at some point in the 11-18 ft-lbs. limit.

This season, bike runs will kick off from all over the country. The vast majority of motorcycle drivers will undoubtedly be assembling for 1 week long festivity all expressing their fascination with bikes. You will hear a number of tales and building tips to chat about with new friends while you drive the days with the bike week. Make sure to ride safe and wear the required safety equipment like carbon fiber helmets. Good luck and have a wonderful ride.

Bear in mind that it’s critical to ensure that you cruise with your bike with safety gear on. Be certain that you keep on authentic carbon fiber helmets.

How to change a Motorcycle Spark Plug:

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