This is the story of the build-up of my cheap Suzuki GN 400.Before you get all upset that it is a jap bike, let me say one thing.I have a 1974 sportster that I finished up a couple of years ago that I ride regularly, I was looking for something cheap that my wife could ride and I wanted to do another build-up.Harley prices being what they are, it was cost prohibitive to build another American bike without selling the sportster to finance it, so I had to think CHEAP.
Last February I started working part time at a local bike shop just to make some spare change and get discounts on parts.My wife ended up getting a job at the same place, running the office and searching the satellite parts locator system for customers and selling used parts.The shop had a couple of service bays but also housed a good salvage yard, all indoors, mostly jap bikes from the 80’s. I located a small bike one I thought would be easy to modify.
The Stock GN400
The GN400 – As It Arrived From The Bone Yard.
My key goals were to find one with a single tube backbone frame, so gas tank selection would be more universal.I also wanted to keep it small and light.I liked the clean look of the single down tube.I looked at a couple of Honda cb 350’s and a cb 360.But the GN 400 had a cleaner looking engine.
I also found a Yamaha XS 650 (this will be a later project)
I scrounged around for another engine, as the engine on the bike was locked up.The front end was bent , so I scrounged another Suzuki front end.
I made him a deal because I was buying 2 bikes and some sport bike wheels, I came home with.A 1980 Suzuki GN 400, a spare front end ,a spare motor, handle bar controls, another Suzuki wheel, and a 1979 Yamaha XS 650 ,and 2 sport bike wheels for $700.
Now I had never seen this model of bike before so I began to search for information on it.The Horse website was very helpful, I found a manual with the help of Wazoo.Then the first order of business was to get the bike running.I swapped engines and hooked up the ignition part of the wiring harness.Cleaned the carb and the sucker fired off!
Okay, so now I have a running bike, my wife is short, just a hair over five feet tall on a good day, so I knew I either had to lower the bike or lower the seat.So I cut the seat support section out of the frame.
Then I welded in some tubing stock to get an idea of how it would look and the height of the seat.Now, remember the Yamaha xs I got? Well because I was going to cut the back end off the Yamaha anyways,, I robbed the shocks and rear fender.I bent some tubing to fill the seat area, but the seat looked funny sitting there all by itself.I went back to the Yamaha and cut the rear frame loop off.Now I had a loop around the seat, this helped to tie everything together visually and also provide my lateral frame support brace.I also used the Yamaha shocks because they were beefier.
I tack welded the seat area together, eyeballing and cross measuring to keep everything centered and lined up.Once this was completed I turned my attention to the rear fender.As you know most jap bikes have very ugly fenders and are usually plastic under the seat.Again, the Yamaha donates the rear fender, the xs 650 fender was long enough to cover the wheel.I wanted to keep the fender close to the tire, I welded a tab to the front of the fender and bolted it to the swing arm.The tire I used on the rear is an odd size, a 130x80x16, the same tire used on the Buell Blast and a Ninja 250, it is slightly smaller than a standard 130x90x16 again, to keep the seat height low.Next I welded some 3/8 steel rod to the rear of the swingarm and ran it up to the fender for struts, I also welded a thick washer to the end of the strut to mount the fender, and pick up the mounting holes in it.I trimmed a Harley fender to fit the front, this took no time at all.
The gas tank! The tank required the most fabrication of the whole bike.The area between the neck and the seat is about 16 inches, about 2 inches longer than a sportytank. So again I searched the HORSE Swap Meet page for someone who had a small tank for saleor trade. Hackasaw came through for me with what appeared to be a Triumph aftermarket tank ofunknown origin. The tank had a very deep tunnel, I needed one with a shallower tunnel, but thetank fit. So I ground the seam on the tank until I could remove the tunnel section. I raisedthe tank and tack welded the tunnel into the right position and made some tabs and fillerpieces to weld into the tank, A by product of this is that I probably gained a half gallonof capacity. I then took the tank to a friend of mine, Scott Morris, who is a certifiedaircraft welder and TIG welds all day on high zoot aircraft parts. He fixed me up, afterwelding I tested the tank and not a one leak or pinhole! Almost a shame to have to bondo overthe welds.
Most of the other fabrication on the bike was minor, grinding to fit ormaking a small bracket here and there. I did make a set of side covers outof 2024 t3 aluminum to hide the battery and electrical components.So After I was happy with the results I disassembled it and finished it for paint.I used epoxy primer, House Of Kolor base coat, and flakes and Mar-Hyde 3 minuteurethane clear. The whole premise of this build was to give my wife a small easyto handle bike, that looked good and would not break the bank.The whole build up required No special machining or fabrication.
The only parts that were bought new was the tail light and blinkers, chain and paint.All other parts were traded for or were scrounged from a salvage yard.I do need to buy a speedo and a tach, I think I will source these from J.C. Whitney as theyhave them on sale.
The total cost of the bike (with new gauges) is right around $650 !!(Yes! That’s right, WAY under $1000 total!) I think this will give my wife a good reliablefun and unique bike, at a FRACTION of the cost of a new bike.
It just goes to show you thatwith a lot of imagination and a little money, and the help of good friends anybody can bein the wind on a custom bike of their own creation. I hope this may inspire someone elseout there to start a cheap project or to get their loved ones involved with motorcyclesand have fun together.
Keep Choppin’ —Elwood
