Innovation on 2 wheels

Norick Abe YZR-500 Replica

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The spiritual successor to the RD-350

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95Racer: 95bhp and 95kg

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Norick Abe YZR-500 Replica

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The spiritual successor to the RD-350

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YZR-500 Frame Kit

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The spiritual successor to the RD-350

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Custom Bike Building

Besides our frame kits we currently offer, we have built quite a number of "one-off specials". This has ranged from fairly straightforward engine transplants to custom-framed bikes, from road-going bikes to racing bikes to drag bikes. You can find lots of pictures of some of these project in our one-off specials gallery.

Among the more popular such projects are:

  1. Transplanting a Suzuki RG-500 engine into an Aprilia RS-250 or Suzuki RGV-250 chassis
  2. Transplanting a Yamaha RD-350 engine (usually enlarged to various capacities using US sourced Banshee kits) into Aprilia RS-250, Suzuki RGV-250, Yamaha 350LC, or even custom built chassis
  3. Updating front and rear suspension with more modern components on various older bikes such as the Suzuki RG-500 and the Yamaha RD-500

Not all our projects leave our workshop as a completely finished bike. More often than not, our customer want us to undertake a certain aspect of their own project, e.g. installing the engine in a frame. They will then take the bike back to their garage for further work, and we may see it again once other specialist work is required. So, we usually see these project bikes more than once during the span of the project, which can be several years depending on the available budget and ambition of the customer.

We also regularly have customers come to us with project bikes started by a previous owner and wanting to correct certain aspects of the bike. This can range from improving suspension geometry, or sometimes just shoddy workmanship. We've seen some atrocious projects over the years!

It is difficult to give a good estimate of this kind of work as everyone of them is different. However, we are confident you'll find our rates very reasonable and our workmanship first rate. Please get in touch to discuss your requirements. Our advise is always free!


We regularly undertake electrical and electronics work ranging from adding a quickshifter to a bike; to installing and setting up an aftermarket programmable ECU, such as those manufactured by Ignitech and Zeeltronic; to installing aftermarket dash units, such as AIM Sport, Koso, and Translogic; to fabricating bespoke wiring looms from scratch.

We have used many of these products on our own bikes and can recommend a product based on your requirements and our experience.

AIM MyChron 3 Dash on the 95Racer

Here is an example of an installation of the MyChron3 dash by AIM Sport. We then built the carbon fibre surround with switches for On/Off, map selection, and quickshifter on/off, as well as indicator LEDs for low oil pressure, neutral gear, and an ECU fault (provided by the standard ER-6 ECU)

Designing and Fabricating a Bespoke Loom

For your Yamaha TZR-250 Hybrid project, we designed and built a custom loom  from scratch. The first step was to draw up the wiring diagram. For gauges, we'd re-purposed the standard Yamaha YZF-R125 units and converted the built-in fuel gauge into a temperature gauge.

You'll also notice that we added a knock sensor. This is a product we intend to release at a future date once we've had some experience with it. It uses a common automotive sensor with a control box of our own design. Its output is connected to what used to be the "engine check" light on the original Yamaha YZF-R125 gauges.

Here is the wiring diagram:

And, the loom fabrication in progress:

Re-purposing Existing Gauge Sets

And, finally, a view of the converted, re-purposed clocks. You can see the temperature gauge on the left side. We also added a shift light, located next to the number 11 in the rev counter. This is programmable via the Ignitech unit. The "check engine" light now serves as a detonation count indicator. This conversion meant that we also needed to get a new clock fascia made.

So, whatever your electrical/electronic needs are, I am sure we can help.

ER-6/Ninja 650 Engine Tuning

If you've read any of the 95Racer blog or browsed through the 95Racer gallery, you'll be aware of the amount of work that has gone into that project. And, of course, it wouldn't be any good with a strong, powerful engine.

The present state of the engine is summarised in the dyno chart below. While we are continuing to make small refinements, we are quite happy with all aspects of it:

Driveability This is not at all a peaky engine. It makes upwards of 40 lb-ft of torque from 5000 RPM all the way to redline, and near 50 lb-ft from 7500 RPM to redline. 
Peak Power Our goal from the outset was a headline power figure of 95bhp at the rear wheel, and that has been reached
Service Interval If you're planning on doing a full race season, you will need an engine refresh during the season. This will be a valve service, and general inspection of all rotating components
Reliability Aside from a failure at the very beginning of the development process, which was due to bad workmanship by an outside vendor before we took control over every aspect of the development, we have not had any failures.

 In brief, the list of modifications include:

  1. Revised intake and exhaust cam profiles to our own specification
  2. Revised valve springs and preload spacers
  3. Extensive cylinder head porting and flow optimisation
  4. Bespoke exhaust system
  5. Revised intake manifold
  6. Enlarged throttle bodies and inlet trumpets
  7. Bespoke airbox and ramair intake system
  8. Lightened, polished, and re-balanced crank
  9. Removal of balancer shaft and addition of electric water pump
  10. Increased crank case ventilation
  11. Reworked standard pistons and conrods
  12. Lightweight flywheel and race generator
  13. Slipper clutch with oil feeds

And here is some photographic evidence of the work.

Due to the many possible combinations of engine modifications and output power, it is best to speak directly to us about your specific goals and requirements in terms of engine performance. However, we believe that this is the most capable engine ever developed from the venerable Kawasaki ER-6. We have seen and heard plenty of wildly exaggerated claims on horsepower, and with it just as many disappointed owners. We dare say, you won't disappointed with this one!

2-stroke Exhaust Fabrication

Over the past couple of years, the 2-stroke motorcycle has become increasingly popular again. Of course, for some this has always been the case. It is the 250cc to 500cc sized bikes that have seen a marked increase in second hand values. Hence, more people are now looking at restoring and tuning these bikes.

As a result, we see a number of customers come to us asking for producing copies of the standard expansion chambers, or bespoke sizing and fabrication of one-off pipes for a specific tune of engine. The most common request for bespoke pipes comes from the RD350LC engine variants. With the pleathora of bolt-on parts available mainly from the USA due to their fondness of Yamaha Banshee quad racing, a seemingly unlimited number of bore/stroke engine combinations are possible.

While many try an existing set of pipes for these engine combinations, we've only seen limited success. A far more effective approach is to use the engine specification to calculate the optimum dimensions for the exhaust chambers. We have now done many dozens of these, and the results have been exceptionally good.

One of the first in the UK to create a 535cc Banshee engined race bike was the 2-stroke tuner extraordinaire Stan Stephens. After several attempts of trying use US sourced Quad pipes, he came to us to produce one-off pipes. You can read more on that story here. Suffice it to say, that the results were good enough to get his bike banned from racing, and we now produce all his pipes for him.

Our 2-stroke exhaust fabrication services can be catergorised into the following stages:

  1. Reproducing an existing set of pipes
  2. Sizing of expansion chambers based on engine characteristics and subsequent fabrication to fit the bike
  3. Full engine simulation to identify improvements beyond just the exhausts
Reproducing an existing set of pipes

This is the simplest of services as it consists of essentially copy what is already there, or fabricating and fitting a set of pipes to customer supplied specification. Costs will vary depending on the complexity of pipe runs, but usually are about:

  • £175-200 per pipe in mild steel, or
  • £220-250 per pipe in stainless steel

Silencers are in addition and can be supplied in either carbon fibre or brushed aluminium sleeve. We usually require to have the bike in our workshops for this service.

Sizing of expansion chambers based on engine characteristics and subsequent fabrication to fit the bike

This is next step up and is particularly suited to people who have a tuned engine where no existing pipes provide adequate performance. In order for us to undertake this service, we either measure the pertinent engine parameters ourselves, or supply a worksheet for the customer to take his own measurement. This service is only supplied in conjunction with pipe fabrication as detailed above.

  • The cost for this service is £250 per specification (usually one per bike)
Full engine simulation to identify improvements beyond just the exhausts

This is the most comprehensive service we provide for extracting the maximum performance from tuned 2-stroke engines. It involves obtaining an extensive data set from an engine, mainly by hand measurements. It goes far beyond the sizing of expansion chambers and creates a model of the engine from airbox to silencer. The resulting outcome can be any of the following examples:

  1. Increase inlet taper between carburettor and reed valve block by 1.5 degrees.
  2. Increase flow coeefficient of transfer ports by 12%.
  3. Lift exhaust ports by 2.4 mm.
  4. Decrease carburettor throat diameter by 3 mm.

This service provides for a nearly unlimited analysis of the entire engine and typically produces over a hundred torque/power curves for customer consideration. As an example, we employed this process during the tuning of our ER-6 engined 95Racer and produced over 200 torque/power curves just for the exhaust section.

  • While the cost of this service is quoted on an individual basis, it is FAR cheaper than shaping metal. It simply wouldn't be possible.

Chassis/Suspension Engineering

If you've ever built a one-off bike or transplanted an engine into another bike, you will have had to deal with chassis geometry. This is a critical but all too often neglected area of building that dream bike. If not done properly, you'll likely end up with a bike that has some undesirable handling traits, or worse, is dangerous to ride. Getting the bike's static attitude, engine location in the frame, front trail, and rear suspension characteristics correct is more important than getting the last horsepower out of that tuned engine.

Rossi's M1

Ever wondered what kind of rear suspension characteristics a championship winning MotoGP exhibits? Well, so did we! Fortunately, in 2007 Yamaha released some details of the previous year's bike (2006) during a press briefing, and these drawings allowed us to model the rear suspension of the M1.

And here is the result in terms of rear wheel rate and the so called motion ratio. As you can see, the wheel rate has about 20% progression over its wheel travel and the motion ratio a 10% increase. This is fairly typical of modern race bikes although many show even less progression, often near zero, and a "flat" motion ration.


A Recent Example

Here is a brief example of a recent "special" that a customer brought to us to sort out a rear suspension problem. He reported that the suspension feels quite soft initially, but then "goes really hard" after a couple of inches of travel. He's come to us after the original builder suggested that he needed a harder spring.

After taking some measurements and running it through the computer modelling, it quickly became apparent that the revised linkage mounting points introduced a huge non-linearity, or progressiveness. This was so severe that the suspension essentially locked after about 2-3 inches of rear wheel travel: The spring becomes more than twice as stiff. Somehow, we doubt that a stiffer spring would have solved the problem.

And here are the plots, first the before, and then after with revised linkage and attachment points:


The remedy was a revised linkage and relocating the mounting point. So, a bit of fabrication and welding. The result was like night and day, another happy customer!

Our Service

As a result of the considerable number of "specials" we've built (or rebuilt) over the years, we have a proven process to ensure that we get the best from such projects.

Typically, this consists of:

  1. If an existing bike, we carefully measuring the existing geometry including head angle, fork offset, swinging arm pivot, front sprocket location, rear suspension linkage and mounting points, etc.
  2. Create a computer model of the bike that allows us to optimise such parameters as front trail, rear suspension linearity and motion ratio, pro/anti squat behaviour; and analyse forces encountered at critical structural points
  3. Propose alteration to an existing chassis to improve any shortcomings

If we are building a chassis from scratch, such as the frame kits we are currently offering, we use the same process but have more scope for an optimal layout. For existing chassis that customers bring to us, there are invariably some compromises imposed by the existing hardware. It has happened, though, that these compromises were too great and a new frame was the only "fix". One such case is illustrated in our YZR500 replica blog.

Of course, we use the same tools and process for our Moto-2 bikes and the race winning 95Racer.

While it is difficult to provide a guideline on cost of this service, we never had a customer complain about the cost, especially given the change it make to the bike and the pleasure of riding it. Please get in touch to discuss your requirement and we'll gladly give you an estimate of the costs.


Banshee-kitted RD350 Engines

Describe our services to build and install RD350 engines:

- show some dyno charts

- show some engine and pipe installations

- describe which combinatins work well, power vs. cost, reliability, longevity, power valves yes/no

- highlight some of the pitfalls, like excessive trenching of the cases for long stroke engines, lock-up clutch (not so nice in a road bike)


Engine Simulation

We have made extensive use of various computer-aided engineering tools in 2-stroke and 4-stroke engine projects. The most extensive use has been for the engine development of our 95Racer project, which has resulted in a reliable engine that now produces over 95bhp at the rear wheel, up from the 67bhp of the standard engine. This gain has not come easily, requiring lots of effort. However, we can categorically say that without the use of extensive simulation, it simply would not have possible. Our experience has clearly shown that knowing which part of the engine represents the next bottleneck in terms of extracting power and torque saves an enormous amount of time wasted in "dead ends".

For instance, we simulated:

  1. Over 500 different exhaust configurations
  2. Over 100 different camshaft profiles
  3. Over 100 variations in cam timing
  4. Over 50 intake runner geometries
  5. Over 50 throttle body geometries
  6. The valve train dynamics to determine the required valve spring rate and pre-load (The standard spring showed lots of valve float above 8500 RPM)

Here are some examples of the cam timing simulations. You can easily see the effect that cam timing has on performance, not all of them positive! Intake is on the left and exhaust on the right.


Quite obviously, it simply wouldn't be practical nor possible to fabricate these permutations of parts and test each one on a dyno. Also, quite clearly, not every project requires, or can afford this level of effort, and so we provide two levels of service.

Exhaust Optimzation

This is a service that focuses primarily on the dimensions of the exhaust system. It requires a minimal set of parameters to be supplied by the customer, yet provides useful information about how to build a higher performance exhaust system. This service is especially popular with our 2-stroke customers who have a tuned or otherwise non-standard engine. We usually charge £150 to perform this service and here is an example (from our Yamaha TZR-250 Hyrbid) of what you receive in return.

It is this same service we supplied to Stan Stephens to get his Yamarilla Banshee race bike good enough to get it banned from competition!


Full Engine Simulation

This provides the level of service similar to what we used on the Kawasaki ER-6 engine in our 95Racer. The cost of this service usually entails 2-3 weeks of work and is priced accordingly. Still, if you're serious about building a special engine, this is by far the most economical route.

An extensive set of parameters is required and the task of obtaining this set of data through measurements and calculations can be significant in itself. We are happy to have the customer undertake this effort to keep cost down. In brief, this service analyses the following areas:

  1. intake system
  2. combustion process
  3. cam profiles
  4. valve train efficiency, incl. valve float and bounce, and valve spring rate and preload sizing
  5. exhaust system including silencer
  6. flow coeffients

Here is an example of the type of information this simulation provides, in this example the outcome of a set of exhaust configurations.

This level of service is quoted on an individual basis and requires a close interaction with the customer throughout the process. Please get in touch to discuss your requirements.