V8 bike project

The ultimate V8 bike project from CBX-Inox.

This project moves on and has some progress once in a while. There will be updates published when there is a new mile stone.

This bike is equipped with a 5.7 liter (350 CUI) Chevrolet V8 engine with MSEFI Pro, 2 turbo's, nitrous and methanol injection.

Every now and then I'm asked about the progress of my V8 project; so did Stefan Reekers in my guestbook. Not a very strange question considering I'm busy for more than five years. On the other hand I'm not too keen on providing any information so I choose this compromise: an update, a glimpse behind the scenes, but not a overall picture. Well, I suppose it's better than nothing ...

September 2002, shortly after finishing the CBX, I decided building a motorcycle based on a V8 engine; in fact a very natural sequel after the sixcylinder CBX. As the Chevrolet is the undisputed godfather of V8 I had no doubt about the choice of engine.
Koen Roemaat, a friend of mine since ages, spontaneously lended me a Chevy smallblock for indefinite time. Lucky for me: it's still in my garage and serves a great job as mock-up.

Of course I visited 'rival' Boss Hoss, situated in Venlo (NL). The salesman certainly did not get the point: "Why build a V8 if you can buy one here?" Well, that's easy to answer: 1. what they sell does not appeal to me at all (lazy chopper-look, too massive, too much chrome, too much plastic), 2. buying = boring, and 3. 50.000 Euro is a lot of money.

Next I made a trip to 'V8 Motorcycles' at Kwintsheul (NL). Result: see Boss Hoss.

I met Theo Verbeet (r) who ownes a V8 Motorcycles-bike. He was quite enthusiastic about it, although the frame revealed a lot of sloppy construction errors. Is that why this company doesn't exist anymore...?
On the left you see Klaus Sarembe: friend, skilled craftsman (he does almost all the welding), dragracer and my most important compagnon during this project. Building a bike is 80% debating and 20% actual constructing; so it's important you get along really well.

Is a V8 engine always doomed to degrade in a chopper frame? No, proven by this beast based om a Dodge Viper V10: the concept-car named Tomahawk. Fantastic design, despite the fact that its four wheels technically makes it a car.

Futuristic, innovative, incredible loud and not allowed on the public highway. Nine replica's were built, each kosting $555.000,-. Not too much money for us Europeans, considering the low dollar exchange rate ;-)

For me it's very important to get this bike legalized: it's no use to build a trailerbike. This one, like the CBX, must make its miles on the road. And, no less important: make its quartermiles on the dragstrip.

Like the CBX the design started in the computer: I modelled my body in a 3D program and did the same with the Chevy engine. My design evolved step by step, not into a chopper or cruiser, but rather into a streetfighter or dragracer. Such a 3D program provides photorealistic pictures and offers great help for the physical realization (milling, lathing). By the way: sorry for the the picture being so out of focus ;-)

Arthur Rottier provided me with an overhauled 5.7 liter Chevy engine, imported from the States. Op eBay I found valve covers, a high-intake Edelbrock manifold and a fourbarrel 600cfm Edelbrock carb. Altogether an impressive powerplant.

I had two 15mm aluminum sheets milled to become the centre of my wheels. Early 2003 I didn't own a mill to do it myself.

Bolted between two 18 inch dragrace rims (10 inch wide) and a - temporary, of course - Bridgestone 275/35-18 car tyre it looked like this.

An airfilter was planned on top of this voluminous intake manifold and huge carb. My design did not include a monstrous tank with a tower piling through, so I had to make a drastic change: eventually I decided to sell both Edelbrocks and build myself an fuel injection system. This would be far more compact and offers some nice new opportunities like putting a turbo on the bike ... or even two turbos ... and injecting NOS. If you're building bigger, why not going brutal?

The wonderful world of turbos was unknown to me until then; I studied books and the internet to get familiar with this matter. Fortunately Klaus and Niels were experienced, and I got some advice from Pjotr Bierman at C&P USA Parts.

My choice had even more consequences: a standard two-bolt Chevy engine would survive the violence of turbos and NOS for just a few seconds, and those extras are not only for showing off. After consulting Ronnie Spijker and John Bakker a company called PAW in the States built me a brand new high performance four-bolt engine. I keep the exact specs a secret, but believe me: this engine can take some beating.Aluminum Edelbrock cylinder heads, some hightech dragrace stuff: let the games begin!

Along it came a lambda probe to watch over the gas mixture, sixteen (16) injectors and a MegaSquirt computer to manage all hardware. Amongst with, yes, two big Garrett turbos. Niels will be 'ma main man' to get this combination running: not an easy job for sure.

I used the 3D-program to design the injection system. First in wireframe followed by solid view.

Willy Naves did the welding the Willy Naves way: perfect (see CBX). He's involved in building the aluminum tank as well.
Finally it looked like this. Note: still far from finished.

Cooling the engine is a chapter of its own. I found Chris Jansen, inspired owner of Hartgers Radiateuren on the internet. His site shows a button called 'maatwerk' (made-to-measure) and that's what it's all about. After some consultations and calculations I started designing the radiator. I made a mock-up from polystyrene foam, he made one from wood and finally an aluminum one. You can see the result on his site at the button 'maatwerk'; where else?

The rear brake started as a massive lump of steel ... transformed to its final shape after many hours milling.
After consulting Rob Westenberg at SO Products I ordered their strongest monoshock. Which, of course, had to be modified.
So I visited a company called GeeWee in Oosterbeek (NL): they have a lot of generators in store.
Marc Michels advised me to mount two TiAL wastegates.
Two HKS blow-off valves prevent overpressure in the intake manifold. I used the computer to choose the right position ...
... Klaus welded the airsupply tube ...
Both Walbro fuelpumps must be integrated in the fuel tank. I designed the construction ...... and this is how The Real Thing looks.
In the summer of 2006 I met Eddie Duine during Nitrolympics at Hockenheim (D). He repaired the exhaust from the CBX and offered to do some welding of the V8's exhaust. So he did, and again he did a good job.
I wanted the mufflers to be made from 90mm tube. At some point these had to be forced to 60mm diameter. This turned out to be fairly impossible: Tubex couldn't press it and some other companies (like Star Twin) neither. So I lathed a massive press mould ...
... but practice makes perfect.
Zodiac mudguards fell victim to the grinder.
This is the rear light. The transparant part is made from a special resin by Cock Springer at PolyStone.

Going from big (the engine) to small (a tap) without revealing a total image, nor information about the frame, the transmission, the exhaust, the handlebar, the paintjob, the seat. All of it carefully evaded. But hey, I think it gives a nice impression anyway.

Have I forgotten to mention anyone? Yes: Roelf de Haan at EPS gave some good advice about the engine and exhaust manifold, Marco Kleijssen clarified troubles with the oilpump. Together with company Holl I fight the War on Threads like UNC, UNF, Metric and NPT (just to name a few), companies like MotoGadget and Eriks give a huge discount on their products to support this project. In the (near?) future Frank Fijlstra will do the paintjob, Lothar Obst will take care of the seat. Talking about 'the near future': I don't have a definite timetable because it's very hard to predict what (set backs?) awaits me. My most upbeat prophecy: ridable and M.O.T.in 2008, paintjob and finishing in 2009, on the road in 2009. Supposing it'll be 2010 it would have taken 8 years. V8 ... 8 years ... 8 in Italian is 'Otto' ... would be quite logical, wouldn't it?

To be continued.

November 21st 2009: after seven years and two months (!) the V8 bike stood on its wheels and the electronics were ready for a test run. The picture shows the current state ;-)

I took my flight case stuffed with a laptop, multimeters, crocodile clamps, fuses and an oscilloscope. On the left top you see a brand new computer*  built 'from scratch' and fully dedicated for this project.

* The first computer did not survive the first intensive test. Cause: due to lack of space a big connector had to be removed and placed elsewhere. The multilayer print did not like that, as I feared. All part of the game.

We prepared for ignition: schemes were consulted ...

... small modifications were made.

... which was no coincidence as the first start was accompanied by many bangs, flames and smoke. The computer-controlled ignition and injection wasn't fully optimized yet which caused ignition in the exhaust.

The lines in the picture were caused by the massive vibrations disturbing the camera shots.

These vibrations required certain items to be re-inforced by Otto.

Ignite - adjust - ignite - adjust. The eight meters are fed by sensors which are located all over the bike. The engine management software is very advanced. Initially the engine run on four, then six and finally eight cylinders. More and more meters came within acceptable range.

The exhaust manifold colored red and heated up to over 600 degrees Celcius.

We were quite excited about the outcome. What a thrill to hear the engine running for the first time.
(Frans in the picture)

Eventually we opened a bottle of Russian champagne: the red color symbolized the blood, the sweat and the tears. There is much, much, much work to be done before the bike is ready for the road.


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 ...


Copy of the orignal article on www.cbx-inox.com :


Yes, September 5th 2010 was quite a euphoric day, it was the day the V8 bike proved to be rideable! So: just a paintjob away from finishing the project? Almost seventeen months later I can tell you this: no way.

Because testing – and riding is just one of them – provided us with loads of data and a long to-do list. First of all: heat. Heat is one of the worst enemies in this project.

I started out making heat shealds for the seat pipes.


Although quite rigid the front fork springs turned out to be not rigid enough. I put in the hardest springs on the market.



The bike has two 40Amp alternators. It turned out that they should rev up earlier in order to nourish all the hungry current consumers. I drew a little scheme to determine the right diameter ...


Chris Jansen (owner of Hartgers Radiateuren) came to the workshop to test the bike's coolant flow.


... after which we took the water pump apart.


To increase flow I got rid of the temperature controller; this bike heats up fast enough.
BennoI found a nifty device called m-Unit which will take its place. I drew this scheme, installed all the wiring and ... it worked.

At the end of January 2010 Niels continued on the bike's engine electronics.


March 20th 2011: I got permission from the company Dekker van de Kamp to use their private roads (no snoops!) for testing the bike. Although it was a perfect sunny Sunday, the results were not that happy: the engine wasn't running smooth at all so I had to heat up the clutch a lot while riding to prevent the bike from stalling.

On the left you see 'newskool electronics' Niels, on the right you see 'oldskool experience' Klaus. Behind Niels you see Frans, representing a very important skill: optimism.


Niels concluded that the cause of the problems might be unclean injectors. So I visited Peter Scheepers (owner of Scheepers Motorsport) in Germany. Peter built a special test rig for the injectors ...


... and tested all sixteen of them. The amount of dirt was negligible which was good. And not good because it wasn't the cause of the ill engine.


Niels called in Gerhard Bekaan, an experienced engine tuner. He took with him some nice testing equipment ...

Tell us, Gerhard: were it the injection coils, the motor management, the spark plugs, the wiring, the injectors? The size of the fuel rails perhaps? Easy questions, difficult answers, even for pros.


Could I affort the extra thickness? No: the small balancing weight under the nut just hit the frame.


On July 3rd we had another testing day with Niels, Gerhard and Frans. It turned out to be the right choice to use the Ford EDIS 8 module because the sparks were significant more powerful than the sparks that MegaSquirt generated.

On the right you see a white heat resistant ceramic spark plug.


October 22th 2011: another sunny day and a perfect day to transport the bike to Scheepers Motorsport. That afternoon I managed to make a few test runs on a deserted road nearby. A magnificent feeling to open the throttle even just a little.


Peter has built his own Dyno. Unfortunately it was too short as my bike is slightly longer then a normal bike. Together with Rainer (on his left) he discussed how to extend this high-tech test facility.


Between October 22nd and the first Dyno test (November 19th) Peter helped me solving quite some annoying problems.

Despite that all brake calipers were 'better than new', the test run proved that braking was still far from optimal. We bled the front and rear brakes thoroughly after which Peter found out that the front brake discs were bent, or 'krumm' as they say in Germany.


Radical action: tearing out all sixteen injector connectors. This was necessary because the wiring was damaged caused by lots of (dis)assemby.


In almost no time Niels and Frans installed new connectors.


You know by now I don't show any picture of the bike itself. Even Peter and Niels had their back turned to the bike quite some time, drawing conclusions from all the data the sensors provided.


You can tell I was a bit worried during the test.

Lothar calculated that the fuel rail should have a minimal inner diameter of 10mm. A table (with no less than nine decimal places) ...
As I wrote before, there's no space for bigger tubes. Another radical choice had to be made: instead of sixteen big injectors – like the one on the left – I changed to 'just' eight small ones (on the right). Can eight small ones deliver the same amount as sixteen bigger ones? Yes they can, and even more than that! These are state of the art Bosch injectors, small in size but very powerful.
Two fuel rails instead of four. But two big ones: 20mm inside diameter instead of 6mm.

This report was just a tip of the iceberg; all the guys above know that.

So what's next? Finishing the new fuel system, testing it. Finding out what caused the engine problems and solving them one by one. Diminish the to-do list. It's that simple.

It's not easy building a complex bike like this, nor is it always fun. But I'm not a quitter, I know what I want and why I want it. So it'll get it on the road, nolens volens.

Wanna hear a time schedule? Won't give it, can't give it. I'm surrounded by professionals, we'll finish this project step by step until ... BANG!


It has been one year since my last V8 update. And another busy year it was.

I completed the documentation on the V8.

Both folders have proven their value over and over since, especially during testing.
On April 7 2012 we did the second Dyno test. Niels again changed the injector wiring as the bike now has 8 instead of 16 injectors.
Less complex wiring, and easier to control with the motormanagement. And some weight loss for even better acceleration. ;)
Me and Klaus (l) enjoy sniffing V8 exhaust gases. It's unhealthy but hey, most nice things are.
Tuning experts Peter and Niels discussed the steps to take.
During testing Klaus kept an eye and a tool on still one of the biggest  challenges: heat control.
Still far too rich but a nice result to end the day with: 357 rear wheel horsepower @ 1,08 bar turbo pressure.

Click the picture to enlarge it.

The rest of the day we fought with the lambda controllers. Sensors and controllers are this bikes nervous system; any problem with any of them paralyzes the bike and takes the day.
June 16 2012: Dyno IV. Again lambda complications took a lot of time – one of them even burned out – as did other defect wiring. Bad luck, but that's R&D.
Tuning always start with a rich mixture: it won't get you the best results but it'll increase the chance that the engine will survive this torture.
Although Peter has some huge fans in his high tech testing facility, for a short while the V8 produced more rich gases than the blowers could abduct.
Autotuning from idle to ... yes.

Okay, some sound too, to get a picture:

Again there was Trouble in Lambda Paradise: faulty firmware this time.

We replaced the defective boost valve ('PWM') by a new Pierburg N75. As you've read above elektronics is a complex matter, not only for us but apparently even for manufacturer Pierburg, as we read in their manual. A challenge: find out the error in one of the three pink rectangles.

Chris made the new cooler and suggested a new, slightly bigger fan. He measured the air displacement of the 'old' one (900 cubic meter per hour) and compared it with the new one (1289 cubic meter per hour). That is 43% more.

That should do. And if it doesn't: it still should.



Last months that Peter, Klaus and Otto visited seventyfive year old bike legend Fritz Egli in Switzerland. We discussed Egli's attempt in 2014 to break his own sidecar landspeed record at Bonneville. And discussed the possibility to take my V8 along with it for the same reason. Nice dream, that's for sure, but priority is getting the bike street legal.

To be continued...