DRP: Derbi Reactivation Project

[toratora]

Some many long time age Dante hooked me up with some Aprilia plastics from some race bikes that they once had a Scuderia. On one of them came this cool little gadget. It's purpose is to enable quick removal of the farings. I've seen them on some race bikes. This tube attaches on the faring, there is a rod that is attached to the bike. The tube fits over the rod, and an R clip holds it in place. As you can see the tube has a well nut on one end, and the bolt has a shoulder so that the faring isn't pinched. Pretty cool stuff. I've been trying to find these, but so far I can't seem to find a vender for this stuff. I did find something similar in FDG's CB350 build thread (that's how I found his thread), but that's the closest I've been able to find.

[toratora]

Whoa Fibaa!

That is so cool!

Since I'm fashioning my own brackets anyway so I might as well figure out the tube thing. These Tyga units give me some ideas. The last trip to the hardware store I discovered that they stock R clips, well nuts, and other bits that are close to what I would need.

If I had a TIG welder I could use aluminum rod, and weld it to some aluminum plates that screw into the frame, replacing the stock plastic mounts that screw into the frame. Then have these tubes fit over them and R clip in. I could also just tap some threads into the end of the rod, and secure it to the brackets. That should do it.

I might even be able to fashion something up for in the belly pan so that I wouldn't need tools down there either. Then it's just figuring out something where the side panels connect to the top. Maybe a screw converted to an R clip could work there too. Something to think about.

[toratora]

Easy Parts showed up today. It took longer than other people's orders because I ordered some stuff they didn't have in stock. But it came fairly quick.

The important parts are the new bars to replace the ones that got messed up when I was crashed by the Honda Driver. I also got the rubber bushing for the front of the tanks since that was missing when I got the bike. I should have ordered the spacer that goes along with it. I'll have to fashion up something now. The other bits are the water pump gear for the crank, and a new nut and washer for the crank. The last item is new top end nuts. These things are for the Senda Project--some time in the future.

[toratora]

The new bars came individually wrapped--like Japanese treats!

Because I didn't have the correct bars for the bike I employed bars from an older GPR, and well they had issues on this bike because they are quite a bit shorter.

Left and right bars use to have different part numbers. It had these things so that the holes that orient the controls have certain locations. But the new bars are designed to be for either side. This is the same bar just rotated about 30°.

Installing the bars.

[toratora]

hmm, I just saw that Derbi also put as aluminum swing arm on the Senda--without going to the linkage. I use to know the reason for using this offset. It has something to do with putting the braking force to the chassis so that the suspension can properly perform, but I really don't remember. Guess some research is in order.

Looking at this photo I think I can see why they did it. With the upper support beam there's no room to have the brake get its support from the swing arm. Comparing it to the image below with the classic GPR.

[toratora]

The stock petcock on this bike failed within the first hundred miles or so. Since then I've been running one from a scooter. The sad thing about that is the fuel sender on this bike is part of the petcock. So I've never really had the luxury of a reserve, or a get gas you idiot light. Which means that I've always had to keep an eye on how much fuel was around. Since that's the case I might as well go for the good stuff.

The Malossi high volume petcock. From these photos you can see it's a huge difference from closed to open. It takes about six revolutions to open it up all the way! I'm planning on leaving the plastic side fills off the bike this time, so I'll be able to sneak my hand in there to shut off the fuel.

[toratora]

I am so looking forward to running this engine.

[toratora]

Thing looks like a beast! So are the stroke crank cylinders just taller so the ports are higher? Or what makes them striker compatible? Wouldn't a spacer work on pretty much any cylinder?

Hey D,

Yeah that's a really good question, and I've kind of played around with it. When the Xtreme 45 seized I pulled out the MetraKit Prorace 43 that I have from a previous bike. I no longer have the 43 crank because I gave it to someone that I thought needed it. Anyway, I tried to employ the 43mm Prorace with the 45mm Airsal crank using some base gaskets to make up the extra space. I was able to make up the space, but the engine wasn't happy. Now as you can see from this photo there was a pretty bad air leak. So that didn't help it run, but I think the real reason is the port timing was all messed up.

The Airsal kit for the Derbi EBE075 ships with a spacer. The stroke on the 075 is 45mm too (turns out it’s actually 43mm with a 95mm rod). I've even thought about putting the Xtreme 45 kit on an 075 engine. This should work, but it needs a spacer to work. But, it's possible that fitter with an Airsal crank that the 075 engine would work without a spacer. I think the difference is in the rod length, and placement on the crank between the Airsal crank, and the 075 crank. Since I have a couple of 075 engines, and there are no longer any kits available for them I will probably attempt something like this as a solution. I may also try a 40mm crank, but that's all future futzing about.

Another thing, from the bottom of the transfer ports to the top of the cylinder is the stroke length. So if you just use a spacer to get the bottom of the transfers to the correct location the stroke will still be off. I knew that with trying the 43 stroke Prorace, but I figured it be worth a shot if I could get it to work.

[toratora]

This is interesting. Barikit makes a 1.5mm spacer.

To use Barikit's crank sustained stroke need these cylinderspacers to raise the cylinder so that the piston does not hit in the top cover!

[toratora]

Progress has bene a little slow thanks to the attention I've recently been giving to the other bikes, but I'm still moving forward with this one. Made some progress with the faring mounts yesterday, and will probably make some nice progress with them tomorrow. This came back today toot.