Suzuki S40 retro mod cafe racer type thingy project

Hi.

This is the start of my Suzuki S40 project. It is a 2007 model, been dropped at low speed before I bought it (maybe a few times), but other than that it seems like an ok donor. Don't think maintenance was the previous owner's highest priority, so will be giving her a full service as we go.

Older bikes are hard to find here (Dubai), so I chose a modern air cooled single that can be styled to look older, and hopefully a bit cooler.

Haven't really made much progress yet, just testing out some ideas and collecting the parts that I have made up my mind on ( I think....).

Here is the bike as purchased:



There is a long list of bits that need to go, including the tank, seat, hideous indicators, huge tail light, front and rear guards, plastic mirrors, plastic headlight, oversized 19" front wheel, forward controls, huge muffler, air filter box, battery box, and most of the chrome.

Just playing around, I took out the bar risers:



and put the standard bar back on, needed to rotate a bit:




The bar fouls the tank before full lock, but have already ordered new bars and got a new tank.

Here is the new steel tank, bad photo though:



Took the green sticker off, keeping the other ones there for now to see if I like it:



Just checking how it would come out, I sand blasted and powder coated the exhaust heat shield to see how the un-chroming would come up. Looks pretty good, this photo was taken at night, it is not as matte as this in daytime:



Bought a fibreglass seat off ebay for $15 or something, it won't make the final cut, but will use it for mockups:



Took all the girly guards off the belt drive too:


Thinking I will put a foot plate on the side of the rear set mount, and keep the rest exposed.

The biggest issue I have with this bike is the back end. This photo of a bobber (shamelessly stolen from internet) shows how the standard frame drops really low:



This is why the RYCA kit uses side covers, to hide this ugly frame.

I sketched up a before and after of the frame mod I am thinking of at this stage, just some initial ideas:

Standard frame:


Modded frame with more upright shocks:


Another major detail I need to decide on is the rim sizes. Standard is 15" rear and 19" front.

The RYCA kit brings the rear up, but I was thinking about dropping the front down with a 17" supermoto rim:



Any ideas on this will be appreciated. A drop in the front will help to reduce the cruiser rake too.

So that is about as far as I have got, if you can call it progress. Some bits should be on the way from Dime City and J&P, will be able to work out some more details then.

Excited to see where you go with this! I think the S40 is a great little platform for building and it would be nice to see one not done my RYCA

I'm thinking hard about using one for a bobber/hardtail build soon

I've always liked these, although they're known as the LS650 Savage over here... tuning in

They're a bit rare here but still would be fun to build something with I reckon...

17s front and rear would be nice and would give you really good tire selection.

I wouldn't make the shocks that upright. It will make the rear end a LOT firmer if using stock shock; a little more upright is fine, but too much and you can make handling all wonky.

Also worth mentioning is that if you modify frame as intended, you make the open area of the frame a lot larger, making the frame more prone to flex (larger triangle). Personally I would keep stock backbone to the swingarm, and then make a subframe that you mount your seat section on.

That's backwards on the shocks, no? With an upright shock the weight is transfered onto it more directly making it feel much softer...or at least that's how I'd logically worked it out in my head

valvesprung said:

That's backwards on the shocks, no? With an upright shock the weight is transfered onto it more directly making it feel much softer...or at least that's how I'd logically worked it out in my head

Click to expand...

I may be confusing myself on this one....

yes, that is true based on torque applied... but i think it has to do with lever ratio (might not be the proper name)... by offsetting the top mount, making it more vertical, lets say each inch of travel of the swingarm converts to 1 inch of compression of the shock. By making it more horizontal, you can make it so that each inch of travel of the swingarm makes it compress less then one inch of the shock. Force = Spring constant x Distance, so as distance compressed decreases, the force required is less, so spring feels "softer"


I might be seriously confusing myself though... its fairly basic physics (and if i was less lazy i could do the calculation and double check) but all these fumes from the fiberglass resin is getting to my head... Can anyone confirm/deny my thoughts? I don't want incorrect information out.

I think you are right Buffy, As the socks are laid down (to a point) the spring rate decreases and as they go toward the vertical they go stiffer. If you're going to get new shocks and go upright it's just a case of finding the right spring weight to go for.
I think upright shocks on your build would look classic. Especially with the forks dropped through the trees a little.

Thanks for the comments, but the new mounting point would need a longer shock anyway.

So I can choose something with a suitable spring rate.

The stock springs actually feel quite soft, for cruiser riding smoothness. And I am on the heavier side, so a bit stiffer would be good anyway.

Regarding the frame, strength, I would be adding a new triangulating member which would increase the overall stiffness (going from swing arm mount to rear of tank).

As it stands, there is no triangulation in the frame, once again most likely due to the fact it was designed for cruising.

Count me in- I like those bikes.

For the rear wheel: cross reference the hub's part #. I "think" it is used on other bikes. If I'm right, those other bikes use 18" wheels (direct swap?)

Thanks for the tip Big Rich, looks like some more research is required

Ok, so played around a bit more tonight.

So I drilled out the studs on the seat, and rattle canned it black (yes i know it looks rubbish, just for mock ups)



With the standard tank and lines, this thing could only work as a bobber:



Now I need the audience to really open their minds, and pretend the new tank does fit down over the old tank mount points, and the whole thing is like 4" lower, and not resting on a plastic box of bolts:



The front will be lower, the tank and seat will be in straight line, and the rake reduced. I hope you can see what I am on about here.....

So to get the tank on properly, it looks like these mount points will be coming off then:



The electrics in this area will need relocation, the big round thing on the right is a solenoid to reduce the compression for starting. The RYCA kit keeps the original gear lever to activate the solenoid linkage by foot. Not my cup of tea, I am thinking a cable operated one, with a second level next to the clutch (my KTM 640 has this).

I got the stupid chromed things of the rear guard too, they weigh a heap. Will look at taking the rear guard off, but I think I need the wheel off first to get at the bolts.

I also pulled apart two junked wire brush stripping wheels, and found one had an electric problem, one had a mechanical problem:


This 1" crown wheel has less teeth than a bare knuckle boxer:


Free tool!


So that's it for today. Thanks for reading this far.

So I found a pair of spoked 18" rims that I wanted. I bought them, and they came with a free bike.

Now I have a Honda GB250 Clubman, pretty much looks like this:



It doesn't have a title, imported from Japan. If I didn't buy it, it probably would have ended up in Iran.

I got the GB home, found that the petcock wasn't letting any fuel through. Removed the tank, hooked up the carb to my el cheapo fuel stand, connected the battery to the charger and she fired up first crank.

Trying to chase up my parts orders from the US.

J&P got nothing for me, told me to wait. I ordered on 6th of Jan, and online shop told me parts were in stock. Email from customer service said it would be 10-12 working days, and they are gone now too. Emailed back again and a non-committal reply.

My other order from DCC reached the USPS on Jan 19th, hasn't moved from Miami yet.

The joys of international commerce

Damn. Bummer about the parts......but that GB is a cool little bike!

Yeah. I like it. I might even try to find one with papers just for shits and giggles.

It looks like I will be keeping the rims, gauges, headlight, tank and seat.

The rest will be going to a friend of a friend who is trying to restore one, and convert to some kind of desert flat tracker.

IF you ever want tosell the GB tank let me know

Looks like the DCC stuff has made it to Dubai, and most of the J&P stuff has left the warehouse.

GMJ - I probably would sell the tank, but it may not be economically viable for you once freight has been accounted for.

My bits came in from DCC:



But I decided the rear sets would be better in black:



I think they came up pretty nice, just need to work out some mounting brackets now....

If you sear there is a company that sells a cafe kit for the S40. They raise the rear, relace the rear wheel to an ~18in wheel. Clips ons and then...

http://www.bikeexif.com/wp-content/uploads/2012/03/suzuki-s40-cafe-racer-5.jpg