Find solution

Motorcycle owners drill out stock pipes to make the factory installed baffles in their exhaust pipes less restrictive. The stock baffles in many exhausts, particularly Harleys, severely restrict an engines capacity to breathe in and out. They effectively diminish the size of the engine, which in turn increases the bikes fuel efficiency. In addition, the more restrictive the baffle, the quieter the engine -- something that pleases people who are concerned about noise pollution. Still, some motorcyclists believe that louder and quicker motorcycles are safer to ride. If you are one of those cyclists, and want to drill out the stock pipes on your bike, you can do so in a series of straightforward steps.

Instructions

1

Unbolt the front and rear mufflers from the exhaust bracket (on most motorcycles) with a hex socket and a socket wrench. The size of the socket will vary by motorcycle. Bikes with very accessible mufflers will not require this step.

2

Loosen the hose clamps that hold the heat shields to the mufflers on most cruiser motorcycles, using a flathead screwdriver.

3

Examine the bottoms of both mufflers for any screws. Remove any screws you find with a screwdriver.

4

Remove any end caps from the ends of the mufflers. End caps are decorative trim in various shapes, including "fishtails," that also limit access to the interior of the exhaust. Some motorcycle exhausts have end caps and some dont. They usually attach with a single screw.

5

Look inside each muffler to determine if the baffles are removable or welded into the muffler. Some baffles slide out after removing an end cap. Harley baffles are welded. Pull removable mufflers out before drilling into them.

6

Chuck a 12-inch-long, 3/8 inch drill bit into an electric drill. Use the drill to bore a

hole in the approximate center of the baffles in both mufflers.

7

Replace the baffles into the muffler shells if you removed them. Replace the end caps and any screws.

8

Replace the heat shields and re-bolt both mufflers to the exhaust bracket where necessary.

The bolts and studs used to assemble a vehicles exhaust system and connect it to the manifold are exposed to extreme temperatures while the engine runs. Because theyre on the underside of the body, theyre also constantly exposed to rain, ice and road salt. Given this operating environment, its sometimes a wonder exhaust studs dont always break while being removed.



When an exhaust stud does snap, however, there are a number of approaches to removing the broken shaft. Start with the first, and keep trying until the stud finally comes out.

Instructions

Heat Method

1

Expose the shaft of the broken stud. Check to see whether there is enough length for a secure grip with a pair of vise grips; if not, go to the next method.

2

Heat the surrounding metal with an oxy-acetylene, propane or MAPP torch. Play the flame over the metal all around the stud, but do not heat the stud itself; you want to expand the metal holding the stud to make the bolt hole larger while leaving the stud its original size.

3

Clamp a set of vise grips securely on the exposed end of the stud, and turn the stud counterclockwise. Do not apply excessive force, which might damage the stud further. If the stud moves slightly, apply more heat; if not, move to the next method.

Left-Hand Drill Method

4

Grind the exposed head of the stud flat with a grinder. This will help prevent the drill bits from slipping off center. Liberally apply penetrating lubricant to the broken stud.

5

Punch a dimple at the center of the bolts surface with a hammer and metal punch. Drill a pilot hole into the center of the bolt with a 1/8-inch bit. Keep the hole centered and straight.

6

Reverse the drill, and load a left-hand drill bit 3/16 to 1/8 inch smaller than the diameter of the stud. Drill straight into the pilot hole with the left-handed bit to avoid accidentally cutting the metal surrounding the threads.

7

Allow the left-hand bit to loosen the stud by its own rotation. Repeat the process with a larger left-hand bit or bits until the stud comes free. Once free, lubricate the hole, and clean out rust. If the stud still will not come out, move to the next method.

Drill-Out Method

8

Choose a drill bit with a diameter slightly larger than that of the original stud, including its threads. The purpose of drilling a new hole is to remove all traces of the old, stuck stud.

9

Drill straight down the center of the stud, following the previous holes, to the full depth. This method will remove the old, broken stud entirely while leaving a straight-sided hole larger than the original. Clean all rust and shavings from the new hole.

10

Insert a thread repair kit such as a Helicoil in the drilled hole, following the instructions packaged with the kit. Use a replacement stud of the original size when reassembling the exhaust system.