Restore and Modify Motorcycle - 1981 Yamaha XS-400
Introduction: Restore and Modify Motorcycle - 1981 Yamaha XS-400
I bought this non-running 1981 Yamaha XS-400 for a couple hundred dollars. Since Yamaha parts are widely available for this model, I knew it would be a low-cost way to get some 2-wheeled transportation. I restored it to working order and after riding it a few months, I decided to change some things I didn’t like about it, and maybe add a little beauty to the world. Every bike is different, but the solutions to the modifications I wanted can apply to other projects, or ease the fear of the unknown so someone else can take on a similar challenge.
The process to get it running involved cleaning and synchronizing the carburetors multiple times, replacing gaskets, cleaning out the gas tank, new air filters, battery, adjusting the valves, new brake pads, replacing the front brake fluid, new piston rings, cam chain tightener, new fork oil, and new tires. Total cost was about $700, the most expensive parts being tires and piston rings. There are other Instructables that go into detail for this part of the project. One cost I did not have to bear was painting the gas tank--a friend did it for free in their shop (thanks, <PERSON>!)
Then the problems surfaced. I rode the Yamaha in the stock configuration for a while, and found that I didn’t like the “cruiser” handlebars. The seat with the hump in it made me sit too far forward and since I’m 6’4”, my knees almost hit the handlebars. The heavy sissybar/luggage rack on the back made the bike look heavy and tired, even though it was very functional. The old shocks were weak and bouncy, so they had to be replaced. 215
I didn't like the long rear fender, the old bulky lights, the big shiny gauges, and the exhaust pipes were rusty and ugly.
So here was the plan:
1-Replace the handle bars with wide dirt-bike handle bars to let me stretch my arms out more
2-Replace the seat with a flat seat, and remove the sissy bar/luggage rack
3-Shorten the rear fender
4-Replace the shocks
5-Replace the lights and turn signals with smaller units
6-Declutter the handlebars
7-Fix the rusty exhaust pipes
8-Other small details
Safety note: any time you make changes to a motorcycle, you may increase your risk while riding. Changes to the geometry are especially risky, so if you change the suspension or modify the seat or frame, be sure the changes don't impair the bike or make it handle worse. Changes to the lighting system can also make you less visible. Be careful!
Supplies
Tools required:
Metric socket set
Metric box wrenches
Phillips head or JIT head screw drivers, large and small
Metal file
Drill and drill bits
Hacksaw
Hand grinder with cut-off wheel (optional)
Soldering gun with flux and solder
Silicone grease (or dielectric grease)
Supplies purchased:
Replacement seat
Headlight
Front turn signals
Rear light/turn signal combination
Turn signal diode kit
Electrical connectors
Step 1: Replace the Handle Bars
The new bars had the same diameter bar as the old ones, so this was a straight bolt-on change. Remove then reattach the left hand grip, right throttle/hand grip, mirrors, levers and switches, then bolt down the new handle bars. Beware that if you also replace the seat and suspension, you may have to readjust the handlebars, along with the hand controls and mirrors, for safety and comfort.
(Also see: https://www.instructables.com/Changing-Motorcycle-Handlebars-Yes-its-that-ri/)
Most of these handlebar attachments used phillips-head screws. A comment about the phillips-head screwdriver: many bikes from Japan use a special type of phillips head, called a JIT. A regular phillips-head screwdriver will work, but doesn’t quite match the JIT cut, so the screw heads can easily get deformed after a number of uses. If you get a JIT screwdriver, you’ll find it fits more snugly into the screw heads, which makes even over-tightened screws easier to remove without damage. A nice addition to my toolbox.
Step 2: Replace the Seat
I bought a generic flat replacement seat. My goal was to eliminate the old seat's 2-level feature. 226