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Main Area => Projects / Builds, Racing and Tech => Topic started by: krol on May 13, 2018, 01:17:00 AM

Title: 1977 GS400 Classic Racer
Post by: krol on May 13, 2018, 01:17:00 AM
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.
(http://compressimage.toolur.com/download/20180512-19-Fvbi2BfGAWNrcx63-t4tpBl/d4bad70a_c093_411f_8_uLJe6.jpg)
Title: Re: 1977 GS400 Classic Racer
Post by: krol on May 14, 2018, 07:05:44 AM
GS400
Title: Re: 1977 GS400 Classic Racer
Post by: krol on May 14, 2018, 07:06:35 AM
GS 400
Title: Re: 1977 GS400 Classic Racer
Post by: krol on May 14, 2018, 07:07:31 AM
I like left turns ;)
Title: Re: 1977 GS400 Classic Racer
Post by: krol on May 14, 2018, 07:21:46 AM
I started with this:
http://gstwins.com/gsboard/index.php?topic=72111

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.

So:
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.
Title: Re: 1977 GS400 Classic Racer
Post by: qcbaker on May 14, 2018, 08:26:52 AM
Very cool! Can't wait to see more.
Title: Re: 1977 GS400 Classic Racer
Post by: alpo on May 14, 2018, 01:01:55 PM
Sweet! I bet she's a blast to ride!  :cheers:
Title: Re: 1977 GS400 Classic Racer
Post by: gregjet on May 14, 2018, 01:24:55 PM
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.
Title: Re: 1977 GS400 Classic Racer
Post by: krol on June 11, 2018, 04:34:13 AM
Hello.

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 :)
Title: Re: 1977 GS400 Classic Racer
Post by: ShowBizWolf on June 11, 2018, 02:21:59 PM
Good luck to you krol!!! I love that blue color :bstar:
Title: Re: 1977 GS400 Classic Racer
Post by: alpo on June 11, 2018, 03:48:03 PM
Good luck!

It looks like you need a new exhaust pipe. Those crimps and holes are not helping performance.
Title: Re: 1977 GS400 Classic Racer
Post by: KHnTX on June 11, 2018, 06:00:57 PM
That is pimp!
Title: Re: 1977 GS400 Classic Racer
Post by: ajensen on June 13, 2018, 02:51:14 PM
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.
Title: Re: 1977 GS400 Classic Racer
Post by: krol on June 18, 2018, 05:19:26 AM
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!
Title: Re: 1977 GS400 Classic Racer
Post by: ajensen on June 21, 2018, 11:33:25 AM
Thanks for sharing the results. Congratulations.
Title: Re: 1977 GS400 Classic Racer
Post by: alpo on June 23, 2018, 03:49:25 PM
Congrats! Racing is about the most fun one can have with their clothes on!
Title: Re: 1977 GS400 Classic Racer
Post by: krol on July 15, 2018, 06:08:11 PM
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.

(https://scontent-frt3-2.xx.fbcdn.net/v/t1.0-9/fr/cp0/e15/q65/37092841_1805990599489225_8357083549932716032_o.jpg?_nc_cat=0&efg=eyJpIjoidCJ9&oh=bc3ad2347fc1f91b210887f291035801&oe=5BD4FB6A)
Title: Re: 1977 GS400 Classic Racer
Post by: sledge on July 16, 2018, 01:04:25 AM
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.
Title: Re: 1977 GS400 Classic Racer
Post by: crackin on July 16, 2018, 03:09:46 AM
Thats a great looking bike, and to be racing it must be a real buzz. I'm so jealous. :bowdown:
Title: Re: 1977 GS400 Classic Racer
Post by: krol on July 16, 2018, 11:21:11 AM
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 ;)
Title: Re: 1977 GS400 Classic Racer
Post by: gregjet on July 16, 2018, 01:01:31 PM
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.
Title: Re: 1977 GS400 Classic Racer
Post by: krol on July 17, 2018, 12:01:39 AM
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
Title: Re: 1977 GS400 Classic Racer
Post by: krol on July 17, 2018, 04:10:37 AM
Title: Re: 1977 GS400 Classic Racer
Post by: krol on July 24, 2018, 01:53:47 PM
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.
Title: Re: 1977 GS400 Classic Racer
Post by: gregjet on July 25, 2018, 12:51:01 AM
A crash and back up to fifth. Noce recovery.
Title: Re: 1977 GS400 Classic Racer
Post by: 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.
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.

(http://czechroadracing.cz/images/galleries/2018-09-09-branna-2018/63.jpg)
Title: Re: 1977 GS400 Classic Racer
Post by: qcbaker on September 14, 2018, 07:38:09 AM
Nice photos, and congrats on your podium finish!
Title: Re: 1977 GS400 Classic Racer
Post by: KHnTX on September 14, 2018, 07:38:53 PM
Congrats!

Sent from my ONEPLUS A3000 using Tapatalk

Title: Re: 1977 GS400 Classic Racer
Post by: The Buddha on September 15, 2018, 03:50:53 AM
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 ?
Cool.
Buddha.
Title: Re: 1977 GS400 Classic Racer
Post by: krol on September 21, 2018, 04:39:04 AM
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!
Title: Re: 1977 GS400 Classic Racer
Post by: krol on October 15, 2018, 02:41:29 AM
Hi,
the last race here (that's only a short clip, but shows how it looks like):

Title: Re: 1977 GS400 Classic Racer
Post by: krol on October 18, 2018, 02:00:48 AM
And onboard:

Title: Re: 1977 GS400 Classic Racer
Post by: qcbaker on October 18, 2018, 07:09:49 AM
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!
Title: Re: 1977 GS400 Classic Racer
Post by: krol on January 22, 2019, 12:48:10 AM
(https://compressimage.toolur.com/download/20190121-19-R5tMFyFbtByX7kUM-FFkiW7/e902e61c_f144_4ad4_9_1OIiH.jpg)

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).
Title: Re: 1977 GS400 Classic Racer
Post by: krol on February 04, 2019, 07:40:48 AM
Work in progress.

Sand blasted, glass bead blasted, finally painted. More soon.
Title: Re: 1977 GS400 Classic Racer
Post by: Andy73 on February 04, 2019, 08:14:18 AM
That is rad my friend, really interesting and great pics! Thanks
Title: Re: 1977 GS400 Classic Racer
Post by: cbrfxr67 on February 14, 2019, 09:13:26 AM
sweee-eet