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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A bit of project history

What follows is a recreation of the blog that previously up on the 3UpRacing site, which we decided to discontinue some time ago. Readers of the blog will be familiar with this project, which started back on 2006, well before any of the current ER-6 based race bikes were built for the Minitwins and Supertwins classes. In fact, the 95Racer is based on one of the first ER-6's to be sold in the UK when they first were released.

Read on for all the details of this ambitious project with the goal of creating the 4-stroke equivalent of the Honda RS-250 racer. The number 95 is significant in that the result was to come as close as possible to 95 bhp in a 95 kg chassis.

Here are a few glamour shots to wet your appetite. The full set can by found in the 95Racer picture gallery

Read MoreA bit of project history

The design phase

Once the engine choice had been made, the detail design of the rest of the bike could be begin. Some of the main decisions that were now required included:

  1. Caster angle and front trail
  2. Fore/aft and height position of the engine
  3. Swinging arm length
  4. Swinging arm pivot position
  5. Wheelbase
  6. Rider position

Read more: The design phase

Construction commences

Having virtually no machining or fabrication capabilities ourselves, finding the right fabricator and CNC machine shop was probably the most single difficult task in the project. Many of the well known frame fabricators in England, for instance, do not really want to build something entirely new based on someone else’s (our) design. For entirely sensible reasons they prefer to stick to what they have done in the past. Most were willing to take the engine, front fork, wheels, etc. and build a one-off chassis based on what they know how to build. The other criteria was to find someone that was not an unduly distance away, for obvious reasons.

Read more: Construction commences

First track testing

When I first approach our master fabricator in early March of 2006, he looked at our plans skeptically and commented that this will be a 2007 bike then. He gave me a funny look when I said that I wanted to test it on track for the first time on August 7th, 2006. Remember, we were stood in my garage looking at a bare ER-6 engine sitting on the floor.

This is where the choice of constructor really makes all the difference. In an incredibly short 4 months, the bike was ready for track testing at Croft circuit in North Yorkshire, England, on August 7th, 2006. As you can imagine, this was a very exciting time.

Read more: First track testing

Development begins

With the next test date set for later in August at Oulton Park in Cheshire, England, we had a surprisingly short list of modifications to make, considering the scope of the project:

  1. Fit larger radiator
  2. Install softer fork springs
  3. Fit new, stronger chain
  4. Correct data logging configuration
  5. Re-map Dynojet Power Commander

Fitting a new radiator became a hunt of what was “at hand” and could be offered up to the bike to check for space. Very quickly, we decided on a Ducati 916 radiator which still needed tapering towards the bottom, as well as modifying the hose connectors. This gives you a good illustration of just how narrow this bike is. It thinks it’s a 250!

Read more: Development begins

First race!

Based on our exceeded expectations of the first few test days, we decided to enter the last races of the 2006 season with Derby-Phoenix taking place on September 23 and 24 at Cadwell Park. Mind you, racing the bike this year was not in our initial plans for 2006.

We were allowed to enter the 750cc/twins class which is essentially the old Superbike rules before the allowed the 1000 cc four cylinder bikes. This class at Derby-Phoenix is dominated by late model Suzuki GSX-R750s. Clearly, we were going to be down on power just a bit. More interestingly, this class runs a shared grid with the 250 cc GP bikes, which is of course our performance target for the 95Racer.

Read more: First race!

What next?

Now with the 2006 season closed, it was time to act on our existing plans for 2007. It was going to be a busy winter…

The main activity would be to significantly rework the engine to get to as close to 95 HP as possible. The engine has been removed and is currently being breathed on by a highly capable BSB engine tuner. Based on his initial analysis of the engine we expect to:

¨ Gain 20-30 RWHP

¨ Dramatically reduce reciprocating mass

¨ Raise the rev ceiling to 12,000 RPM

¨ Reduce the overall weight of the engine by 10 kg

Of course, this will also require a completely new exhaust system. We will publish the power and torque curves as soon as we get the bike back on the dyno.

Read more: What next?

Ramair intake system

Well, it seems my updates are like the proverbial buses that only come in groups with lengthy gaps in between. It must be the chilly weather we are now having that keeps me from spending too much time in a cold garage.

In any event, I am pleased to have finally completed the required carbon fibre work a couple of weeks ago. I have to admit that had I known how much work this would require, I’d not had started it most likely. Still, I learnt lots and not least have a much greater appreciation for the people who do this professionally, and why they charge what they do for one off work.

The main features of the new air-box configuration are:

  • much larger volume (~15 litres)
  • true ram-air system with air passing directly through the head stock
  • monitoring of air-box pressure (and vacuum)
  • accommodation for ECU, PowerCommander, and exhaust gas sensor amplifier
  • tunable bell mouths for shape and length
  • reduction in weight
  • semi-structural front air scoop to carry dash-logger and upper fairing

Read MoreRamair intake system

Engine development

One of the items we identified pretty early on was that we wanted to shorten the left side of the engine. This is where the starter gears, flywheel, and generator live. To save weight, we wanted to eliminate the starter and its associated gears and so went a little bit further.

Read MoreEngine development

Finishing the Ram-air System

My available time over the last two week has been taken up with producing some more carbon fibre components. I am pleased with the progress achieved in terms of the process itself and learnt a tremendous amount since the beginning. After reading more than a fair share, I've started using pre-preg carbon fibre as opposed to wet-lay and vacuum bagging. The resultant parts are considerably better quality and the process is actually easier since you don’t have to bother with wet epoxy and its related clean-up. Although, it does require storing the pre-preg material in a freezer (good thing there’s a full size freezer chest in the garage), and a well controlled curing oven, which we built ourselves. After some research, I decided to try Sprint 85 as the pre-preg material which is made by Gurit. And, the early results are very encouraging. It is a two layer carbon fibre material with a layer of epoxy in between. This makes it easy to lay-up dry and it then takes 10 hours in the curing oven at 80 deg. Celsius with carefully controlled temperature ramps. Vacuum bagging is still required, of course.

Read MoreFinishing the Ram-air System