V8 on the road first time...


A new update from Otto at www.cbx-inox.com


On Sunday September 5th 2010, after building exactly seven years and 51 weeks: the time had come to test the V8 on asphalt. The thrill is hard to describe but I'll try anyway.


But first of all I'll picture the nine months since the last V8 update (November 2009). This report is quite extensive but still it's no more than an impression of all the work.

For example: this is a part of the rear brake system: I cut out a piece from a thick steel plate ...


But the result was rewarding.


Both rear brake cylinders* originate from a CBR600RR and must be connected.

* in the rear rim I mounted two brake discs, each with a six caliper brake unit; I prefer stopping this 1000 lbs bike with good brakes. ;)

Before you realize it, two long evenings are spent.

  As so often, most of the work remains unseen. But that doesn't really matter: the challenge is designing and creating, and if it turnes out to be functional, that is very rewarding.  
  Talking about challenges: The Clutch. The easiest solution would be to put in a Boss Hoss transmission but that wouldn't be fun, would it? After long discussions with Klaus I went looking for a lock-up clutch. I met Danny Bellio, a Belgian dragracer.  

He sold me (correction: he almost gave me) a clutch of a 4000 hp methanol dragster.

An impressive unit. The principle is like this: the six arms move outwards by centrifugal force as the engine revs up, thereby pressing the clutch plate until it stoppes slipping. The more revs, the firmer the clutches grip.


I didn't want to depend just on the revs to drive off. So I designed a hydraulic pressure group in 3D Studio Max in which three hand-operated plungers press the clutch plate. This way I can accelerate at lower revs; at higher revs the arms take over.

In CorelDraw I made a drawing and a action plan of all the production steps; just one mistake in the sequence, one miscalculation, and I could have started all over. And I do not like that: if possible measure twice, produce once.

  Ready for testing. A nice idea doesn't automaticly mean it does its jobs properly. Reality is sometimes cruel.  

A company called Goedhals produced the so called 'pri axle'*, based on a drawing by Klaus. This is Gerard Willemse, he's into dragracing as well.

* not too sure about this translation...


Let's take a brief look in the gas tank, in which I made a lot of changes: two Walbro fuel pumps* with four fuel filters and hoses for returned fuel and venting. The complete construction is bolted as lid to the bottom of the gas tank. Never to see daylight again. I hope.

* these fuel pumps deliver 255 liters per hour each; at full throttle a V8 is very thirsty.

  ... somewhat looks like the ones on the CBX.  

Despite that he offered five saturdays to pull wires, solder, tune and curse once a while. Sometimes because of (at first) inexplicable problems, sometimes because of the cold; last winter was a very cold one.


Technically this is way beyond my league. De electronics will calm the uncontrollable raging bull to a manageable bull.

Together with Frans (on his right) wire after wire was connected and tested. On the bottom part of the picture you see a giant magnifying glass.

  This is the most extensive application of the MegaSquirt motor management system ever. Even the manufacturer benefits from this groundbreaking project because Niels occasionally detects a design error, and finds a cure.  
  The MotoGadget speedometer was connected to the computer and the vast amount of sensors.  
  This picture shows you the back side of the engine; on the left you see the trigger wheel sensor, on the right the oil pressure sensor.  

The oilpan turned out to be a time-consuming and costly setback. It was completely hand crafted from stainless steel. The many welds distorted the integrety so much it wasn't possible to fix it: each new weld would further deteriorate the pan. At such times I hate stainless steel.

So I took a deep deep breath and started a completely new oilpan, this time of aluminum: a sheet, two butt straps and a solid block were the ingredients. At the top you see the 'old' oilpan.

Klaus welded the parts professionally. That's important because any spilled oil would stick immediately to my rear tyre.


While testing the engine it was soon evident that it produces a lot of heat. And because I am, unlike a Boss Hoss, posititioned over the engine instead of behind it, I had to find a way not to be roasted. So I designed heat shields for the valve covers and exhausts. First in 3D, then 2D

... followed by perforation 'by hand'. A highly concentrated activity during which you can't afford any calculation error.

  ... and welding.  
  The silencers got their own shields. No pictures of the mounted shields, this would reveal too much.  

An industrial area outside of Nijmegen was promoted to Area 51. Niels connected his palmtop computer to the MegaSquirt to make datalogs while riding: every single behavior of the engine is recorded.

You can see that the bike is eager to ride.


"Is the bike ready? Can it hit the road?" Well no, it can't. This first testrun supplied us with loads of data.

Niels literally experienced that the heat problem 'is not yet fully resolved' (to say it gently). You can see a burn mark on both trouser legs...

So there is still much work to be done. But the fact is: it's a bike, and it runs!

... to be continued ...