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1977 GS400 Classic Racer

Started by krol, May 13, 2018, 01:17:00 AM

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Some time ago I have created a hello topic in meetings category of the forum, now it's a good time to move some news posted there to the proper topic.

I'm building a 1977 GS 400 to use it in the Classic Motorycle Cup.





I started with this:

What has been done:

Actually, every part of the bike was inspected, cleaned and lubed. A lot of parts was replaced (obvious).
At the very beginning, motorcycle did not start. Ignition job helped.

A frame was slightly cleaned (removed not needed parts).
Tank comes from GS450 or GSX400, I don't remember

Carbs cleaned, K&N pods installed.
Head intakes slightly corrected.
Because it was restricted version (20kN), cams were replaced (these come from GS450 I think, the highest cams and longest opening angle). Also, intake was slightly restricted, it was cleaned too.
Original ignition is out, replaced by electronic ignition from GS500 (with a module and coils).
Front forks have progressive spring, rear KONI Special D, both disassembled, replaced sealings and oil.
Exhaust shortened (old were rusted, too heavy and too long).
Clipons from modern 125cc yamaha if I remember correctly
Rear sets from some '80 Kawasaki, I think they are aftermarket.
Wheels have chromed spokes, blasted hubs, and Heidenau RSW K65 on them.
Brakes regenerated, steel braided line.

Some cosmetic things to do before the Cup starts, but it mechanically it's a good starting point - every aspect is reliable, an engine is almost not touched, should work fine. I can focus on the track instead of on the bike.


Very cool! Can't wait to see more.


Sweet! I bet she's a blast to ride!  :cheers:


I so miss racing. This is racing at it's best. Rider/mechanic etc etc all inb one.
Looks like such a fun class. We had a couple of similar classes where I used to live.



It is almost ready. Still, front fairing waits for being mounted, as well as slight adjustment in the front suspension and carbs jetting (well, I've changed the main jet only, from 112 to 132, and it still looks lean. Pilot jets were not changed yet, but I have to take a look there too).
I modified ignition - it is more advanced now, don't know exact values, but is better.
Unfortunately, now engine pulls quite well and it shows that clutch can't stay it - it slips.

There is no much time left for preparation - on Saturday my first real race in the cup. Wish me good luck :)


Good luck to you krol!!! I love that blue color :bstar:
Superbike bars, '04 GSXR headlight & cowl, DRZ signals, 1/2" fork brace, 'Busa fender, stainless exhaust & brake lines, belly pan, LED dash & brake bulbs, 140/80 rear hoop, F tail lens, SV650 shock, Bandit400 hugger, aluminum heel guards & pegs, fork preload adjusters, .75 SonicSprings, heated grips


Good luck!

It looks like you need a new exhaust pipe. Those crimps and holes are not helping performance.



Cool--have fun, gas it up, and stay on two wheels. BTW, I used to race dirt track, so I still like left turns more than right turns.


Hi guys!

My first race. Fifth place. Great great success! My racing GS has had a small issue with the oil leak (in the place where an electric starter should be installed), small issue with the wrong carb tuning (well, pods and CV are hard to tune), but in general it had run great!


Thanks for sharing the results. Congratulations.


Congrats! Racing is about the most fun one can have with their clothes on!


2 round of the cup finished. 5th place!

First shot found over net, but for sure will have more.

As soon as an onboard video is finished, I will put a link here.


The older GSs suit the classic cafe racer look. You need that horizontal line along the seat and tank bases and a horizontal headlight fairing edge to make it work effectively. Practically impossible to achieve this with the modern version.


Thats a great looking bike, and to be racing it must be a real buzz. I'm so jealous. :bowdown:
No matter what i do to it, it's still a GS
It's not how fast your bike is, it's how long you are prepared to hold the throttle on.


Sledge, it's not the caffe racer. It's real racer. ;)
It is not that fast though. Definitely needs proper tuning.
But in the other hand: I have been fighting against riders on Honda CB four and Yamaha RD. other 4t 2 cylinder motorcycles were far far behind ;)

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