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
So, the "95/95" brief has its origin in creating a new kind of motorcycle that mimicks the behaviour of the, at the time fast becoming obsolete, class of 2-stroke 250cc race bikes. Arguably, the most successful of all was the Honda RS250. So, after having ridden and raced RS250's, we chose it as the blue print for the 95Racer.
One of the most critical choices was always going to be engine. Small, light-weight, powerful 4-stroke were (and still are today) fairly thin on the ground. One that we looked very seriously was a prototype being shown by a company called Maxsym whose aim was to produce purpose built racing engines. These engines were to be available in 500cc and 600cc capacities. The attraction was that they were claimed to be very light and still have a well above average specific horsepower output (claimed weight <40kg, output 90+ HP).
Our second choice was the then brand new Aprilia engine that was to be used in their new Supermotard and motocross bike, the RXV450 and SXV550. This engine is little jewel. It is tiny and weighs below 30kg.
Another engine we considered for only short while was the Suzuki SV650 engine, but we want something fresher. In the end we chose the ER-6 engine because:
- Our first choice, the Maxsym engine was deemed far too risky and this proved to be the correct decision because a full year later, this engine is still under development and it’s projected cost doesn’t leave much change from £10,000! It later turned out that they ran out of funding and the company closed down.
- The Aprilia engine, after direct consultation with Aprilia’s racing division was not likely going to give us anywhere near the engine output we were ultimately looking for. Even the factory racers are only just breaking the 70 HP mark. Plus, at that time it was a brand new engine with some significant teething problems.
- The SV650 engine while certainly capable was deemed too big and too heavy to meet our packaging and weight goals.
- The Kawasaki engine was new as well but being a mass produced engine for a commuter bike, it seemed a fairly low risk path. After initial inspection it seemed to offer plenty of tuning potential and even sports a cassette gearbox.