Suzuki GSX400 Four Cafe racer with USD fork and monoshock


Suzuki FTW
Time to put my project on here as well!

I'm Willem, a 21 years old mechanical engineering student from The Netherlands. I like bikes and especially like tinkering on things and working out a plan for it myself. Last year i worked on a school project which was about building an electric racing motorcycle something completely different than a cafe racer ;)

Enought about me, lets talk about the bike.

The bike i bought in January was a Suzuki GSX400 Four from '83 with over 80.000 kilometers on the clock. I came across this bike because of the price of 110 euros and because of the fact that is something different than the standard Honda cb's and such (no offense :) )

In the meantime i did quite some changes, for now I am just gonna post some pictures and if you guys have any questions veel free to ask. :D After this I will try to update this topic on a regular basis with some info of course. Enjoy!

Some pics of the condition the bike was in when I bought it:




Dirty carburators, bad electrical connections




First step: cleaning and try to get it running.

2VteT6B.jpg ;D ;D

And more disassembling:





I see potential

Engine block was next, replaced all the gasket, new piston rings, valve oil seals and 0.2mm milled of the head to give it a bit more compression.





Some of the goodies I bought for the bike:

Kawasaki ZXR 750 USD Front fork, disc, calipers and clipons, GSX-R 600 K4 rearsets, digital speedo etc.





Also found a CB550F rear rim and a GS550 front rim, those are the same sizes as my original wheels so I can my tires.

Subframe has been replaced with a new one, put a brace on the swingarm and mounted a Kawasaki ER6 rear shock.

Complete pictures so far:



And also managed to get it running again after the engine rebuild, really satisfying my first ever engine that I took apart :

More things to come! :)
Nice work so far, keep the pics coming
Im in to see the final product

Working on producing some wheel spacers and brake disc adapters on the lathe. But next week exams again so have to focus on that first. After that I'm going to start with making the new wiring loom.
Welcome in mate , some big changes going on in this build ,hats off to you Willem doing a great job so far you got skills for sure keep up the good work always here for Q & A's
Thanks a lot! I like to make something unique instead of the standard cafe racer changes. Modification on the subframe and swingarm are the only thing I didn't do myself because I am not really familiar with welding yet.
Ime the same, prefer doing as much as I can myself, bought a small lathe and welding gear watched the dvd's of "how to use" and away I went , love using the lathe aint buying special one off spacers any more just turn my own yeah look forward to your updates mate
That's the right spirit, yeah! I like using the lathe as well, especially after making a nice 3D design of the part that I have in mind and producing it. Also saves quite a lot of money compared to having everything produced by some company.
Small update!

Finally had some time to machine a couple of parts, front wheel spacers to get it nice and center, spacers for the brake disk because of the bigger front fork and a mounting plate for the ignition key switch. Hopefully everything fits right away, last time I did something wrong with measuring. :-[


The upper triple clamp that I designed is waiting to be CNC milled:


And also started on the design of the seat:


It's just to get an idea of the shape that I have in mind. It definitely needs to be a bit lower and the tank is going to be chopped as well, the length is just not right.
looks nice. are you gonna use a wider rim on that hub? I think it might look strange with a skinny tire and that beefed up suspension.
No I am sticking with stock size rim wise. If it looks really of in the end I can always go with a wider rim then. But for now I don't think it will look that strange.
Really nice work :) Then I see the seat, I thought you said you didn't want to go traditional cafe? Thought maybe you would have done something a little different. But that's just my opinion ;D Keep up the good work!
Guys don't worry as soon as the tank is modified I will redesign the seat as well. I agree that it's to standard now. :-[
I think the seat would look better with either a narrower tank or smaller tank altogether. That tank still looks huge even in comparison to the wide four cylinder.
Here's a top view pic of the tank:


As you can see it is quite narrow. I think it will look fine when this tank is a bit shorter.

Luckily the spacer for the brake discs fit perfectly:



The plan is to install the new bearings tomorrow and check if the spacers for the front wheel are perfect as well.

Next step wil be to drill the correct holes in the brake discs as well. ;D


Doesn't look to bad I think. 8)
the twin disks look great. does this setup let you keep using the speedo drive? i stand by my statement that it would look best with wider rubber. there are other performance benefits too 8)
Thanks, I bought a digital speedo setup with a magnet as sensor, so that won't be a problem.

I am gonna think about it the idea of the wider rim and tyre. Any idea what tyre I can fit on a 1,85" 19 inch rim max? Standard size is 90/100/19.

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