1977 Yamaha RD400 Racebike

This is my first big project and my first racebike. It took me quite a while to get this thing up and running. I think I finished it sometime in 1997, so it was a few years ago. I started with a used 1977 RD400 that was a complete runner. It had a set of pipes and was well tuned, after a short test ride I was hooked. I think the project took 2-3 years to finish. I modified a set of Honda CB1 forks and wheels to fit. The bike came with a set of Fox shocks that I rebuilt. The CB1 forks were revalved using a Race Tech gold-valve kit and help from my buddy Dave*. The bodywork was some crashed stuff from a TZ250 donated by fast racer dude and all-around good guy Derek McKelvie King. Rear sets came off of a CBR600, brakes came off the CB1.

1977 Yamaha RD400

I did put some work into the motor, I put in a set of light-weight racing pistons and did some port work on the cases and cylinders. Dave gave me Phil Flack’s number and he gave me a few good tips that I put into use. I installed a set of Dyna coils and some K&N individual “pod” air filters. The bores, heads and carburetors remained stock (well, except for a jet kit). I also put a set of new Proflo pipes on it. On the dyno, it put out 50HP at the rear wheel, not great, not bad. It really needed a bigger set of carburetors. Was a blast to ride…

Though it was fun to ride, it was not a good racebike as the gearbox was too “short-geared” and it had a bad habit of dragging its pipes.

*David McGrath: fast racer dude and all-around good guy…

4 thoughts on “1977 Yamaha RD400 Racebike

  1. I will kiss your (*ahem) if I aint sitting here on the exact same bike right this minute.i bought this bike several months back and slowly have gotten it tuned in right again.im in Georgia ,not sure where you may be from but its gotta be the same bike.

  2. Man that bike brings back some memories. My dad is Derek king I have old pictures of him racing the 250 gp series on his bike that looked just like that. Cool to see where all the old parts went too.

    1. Hi Alec,

      Thanks for the message. I knew your dad back when I was working at KWS in Charleston. He and his dad visited us a lot in the shop, we would always chat about bikes or the Minis. Good times. You can probably find a few pictures of us together at the track (Daytona 97/98/99). Look for the Blue Yellow and Pink bike with the number 90. I was the frowny guy in the team photo ;-).


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