Honda Shadow Bobber - Part 2

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This post has stuff about a previous relationship. My perspective has changed

This week I had a couple of setbacks with the bike. The first was my seat and second was the exhaust. Basically this means I’m going to have to start spending money.

The great thing, and the reason for doing all this, is that I get to learn about motorcycles, how they are constructed and tuned.

Seat take 2

My experiment with the seat didn’t work. I made it too short and too skinny. It is not comfortable at all. My goal is not 100% comfort—I can deal with a little pain in the tailbone, but I would like to be able to ride the bike for at least an hour at a time.

So I went back to the drawing board. I thought I would pattern my new seat after the classic Harley’s the military use to use. It would have been something like this:

Harley-Davidson Motorcycle by Infidelic on Flickr

The dimensions are 18 inches wide by 16 inches long. I found a nice high-res photo of a reproduction seat, imported it into Inkscape and traced the outline. I was then able to print it out and place it on the bike for comparison.

Motorcycle Seat Template

Seat next steps

  • Get some 15 gauge metal
  • Create a mold to fit the contour of my backside
  • Hammer the shape out until it fits the mold
  • Pad with high-density foam and cover with leather

Exhaust

Removed exhaust

I admit that my primary reason for wanting to hack my exhaust pipes was for aesthetics. However, I had also hoped to gain some extra performance in terms of horsepower.

I went to work, removed the pipes and chopped them off with my handy grinder. Half way through the front pipe I realized that it actually had a heat pipe around the actual exhaust pipe in addition to the heat shield itself. The actual pipe is only a mere 1 14 in diameter, which looks pretty puny. So, back to the drawing board here too.

Chopped pipes

As it turns out, if you chop off your exhaust pipes you lose backpressure. This results in a loss of horsepower in the low range. It also means that fuel consumption goes up.

Exhaust next steps

  • Replace exhaust with wider pipe
  • Add baffles/torque cones to increase backflow
  • Re-jet the carburetors
  • Wrap pipes with heat tape

Frame modification from last week

Chopped seat and pipes

As promised, here is a picture of the modification I made to the frame, just behind the seat. I chopped off the portion that protruded over the rear-wheel. I was going to weld on a new fender, but I think I will leave it off because I like the look. I will, however, need to close up those holes. They look pretty ugly.

This is part 2 in an ongoing series of posts about converting a Honda Shadow into a Shadow Bobber. Check out the shadow bobber section to read more.

Harley photo by Infidelic