Noisey Exhaust Pipes
Every Harley Davidson motorcycle is equipped with a pair of exhaust pipes that have a muffler built in them. This is done to provide a little back pressure as the engine runs. The old motorcycles tend to be kind of loud with the plain stock exhaust pipes on them. It’s just that chopper riders have wanted their rides to draw more attention. That is why they have come out with a set of pipes that run without a muffler in them.
These real noisy exhaust pipes are known by two different names. They are called straight pipes and or drag pipes. Any engine running with them cracks loudly when the rider revs it up and quickly lets off on the throttle. This type of exhaust pipe seams to work fine when the motorcycle is ridden at the sea level. That low altitude adds enough natural back pressure to make up for not having a muffler in them.
Back in the eighties most of the chopper riders didn’t like Sportsters. They generally rode a Shovel or Pan Head. Sportster riders that had a bike with a thousand CC engine could find a set of exhaust pipes that made their ride sound more like a Shovel Head. Those were straight pipes as large as those used on the larger bikes that narrowed down at the end that connected with the motorcycle head. They would clamp on just like the stock exhaust pipes did.
Bikers With Old Socks
It’s just that this form of exhaust pipe had one serious draw back. Old Harley engines tend to suck some air back into the exhaust pipes as they are shot off. Drag racers had other bikers shove grease rags into the exhaust pipe ends as they shut their drag bike off when ever the temperature was around fifty degrees and or rainy. Chopper riders could get one of their friends to help them do that with some old socks whenever the same weather surrounded them. Some of them would make sure the socks stayed in the exhaust pipes all night so they didn’t have to worry about any thing messing up the exhaust valves.
There is a drag bike baffle that bikers who used straight pipes could stick into the exhaust pipes when they started riding at a higher elevation. This little piece is round and the same size as the exhaust pipes. It has some small pieces on the inside of it that resemble fingers. The user just has to figure out how many of them should be pointing inside towards the middle. The rest can just get bent up out of the way. Once this mystery has been figured out the baffle just has to be bolted inside the set of drag pipes. One baffle into each one.
With this type of exhaust pipes the engine still roars. It then has some back pressure which gives it more power climbing any mountain. It’s just that they don’t give enough to let the biker pack his old lady and camping supplies on some run in the Rocky Mountains. The elevation gets too high.
In order to fight that loss of power and still have a Harley that roars another type of exhaust pipes has been developed. They look just like straight pipes. They are a pair that actually have baffles in them. The shape makes it easy for a chopper owner to switch from straight pipes to them. The exhaust pipes fit easily around a pair of forward controls just like the ones they replace did. The exhaust pipes are still loud enough to get the Harley chopper rider in trouble while in some place that has an exhaust pipe noise restriction. Some users continue to stuff the exhaust pipes with old socks as the engine gets shut off during stormy weather.
Not every place allows motorcycles to make a lot of noise. Many of them only allow stock exhaust pipes. Harley riders there don’t have to worry. Old iron head Sportsters are very loud with the baffled exhaust pipes. It’s just that the bikers who still ride one of those old choppers with a set of forward controls have a hard time changing back to that kind of exhaust pipe. The forward pipe rubs up against the rear brake fluid container because that part has to bolt on the forward control on the same side as the exhaust pipes run.
The front cylinder exhaust pipe needs to be dented inward when it rubs against the brake fluid container. That inward dent doesn’t make any difference on how the exhaust pipe performs. It already has a muffler in it so no extra back pressure is added. When necessary the Sportster chopper owner can use stock exhaust pipes and renew enough back pressure to ride up at any altitude. He can pack his old lady and a lot of camping gear. That old four speed transmission isn’t a problem any more.
Custom Parts Tools
To get some things done without spending too much many chopper riders have had to learn how to use the hack saw they inherited. A few clues help: Hacksaw User Manual.