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1977 GS400 Classic Racer

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

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You might want to get a LiFePO4 battery. BIG reduction in weight ( one for you bike should weigh about 800gms).
That dent in the right pipe will be chucking positive wave reflections back into the cyl maybe even enough to push stuff out the inlet ( not sure the cam timing is a big as the GS500). A new or repaired pipe might be a go. On a street bike you propably won't notice , but on the track you will. It's a very hard transition dent.
Are you racing RD350's or 250's.


Hi gregjet, thanks.

I was thinking of lifepo battery, now I use 4Ah less than 1kg battery, 0.5kg is not a lot of reduction, but still it is a reduction.
I know this dent may be an impact, new pipes are waiting to be cut and welded :) 2-in-1 is the way to go - this is at least 5-6kg weight reduction.

Cams I use are stock GS450, they already have higher lift than restricted GS400, that's for sure. Next year new engine will have custom cams.

I was racing RD350 and CB500Four




Another weekend, another race. 5th place. I was fighting for 3rd, as my qualification time was 3rd, so was position at starting grid, but had a contact with rear tire of my opponent, crashed, and at the end finished 5th... racing life.


A crash and back up to fifth. Noce recovery.


Hi there,
another 2 races done. And first real success!

Poznan Racing Circuit, Poland: 2nd place. The only one rider that was out of reach was the one on highly tuned RD400.
Road Racing Branna, Chech Republic: well, it was "regularity" race, where I scored 6th place, but in the actual (not officially counted) race I finished 8th.

The most important is: Suzuki did great great job! During this (my first) season I improved my skills A LOT. I love it.


Nice photos, and congrats on your podium finish!



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The Buddha

Quote from: krol on September 14, 2018, 05:41:53 AM
Hi there,
another 2 races done. And first real success!

Poznan Racing Circuit, Poland: 2nd place. The only one rider that was out of reach was the one on highly tuned RD400.

Whaaaaaa who lets a GS400 run against a RD400 ? has that ever come out in favor of the GS, except when the RD400 is needing a rebuild ?
I run a business based on other people's junk.


Most classic races in Europe classifies every pre-78/pre-79 500cc twin into the same class, usually: V class.
And yes, fully serviced, not modified RD400 has 44hp (factory spec), RD350 (more popular here than RD400): 39hp.

GS400: 36hp.
It is hard to say that RD400 is always better than GS400, even though you can clearly see that on straight it is just faster.

Mine GS400 is already slightly tuned, electronic ignition, different camshafts (although a factory spec, they come from GS450, and that's a difference in comparison to restricted (27hp) GS400 camshafts), open intake, proper jetting of original carburettors. On straight mine goes as good as RD350.

Don't forget about riders skills too :D

Don't worry, a new engine was bought, and is waiting to be tuned in one of the best Classic Suzuki specialists here!


the last race here (that's only a short clip, but shows how it looks like):



I don't really have anything to contribute, except that I love this thread lol. Even if you don't get too many replies, please don't think that nobody is interested in what you're doing. Your racing stuff is awesome to follow and I wish you the best of luck in your next race!


Will they fit? Yes, they will!

In a meantime another engine was found. This time I was lucky, and it's gonna be a base for future modifications (like fitting those pistons).

Also, new carbs are waiting (Mikuni vm type).


Work in progress.

Sand blasted, glass bead blasted, finally painted. More soon.


That is rad my friend, really interesting and great pics! Thanks


"Its something you take apart in 2-3 days and takes 10 years to go back together."

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