Originally Posted by 2T Institute
That's a TZ125 4JT frame not an Aprilia. Have used the 14 X19 small end in a kart motor that lived at 14,000 only one to fail was when we were forced to run a bearing for the extra meeting when the supplier was out of stock. With the width of the bearing according to my crank bloke( a clever Kiwi as well) there was a certain year TZ that switched to a wider bearing, with the rollers poking out the sides of the rod, that solved lots of small end drama's on the previous model.
Well i bow my head in shame. nah not really i just thought it looked to right to be a Y.A.M.A.hoo.
Does explain why it is striped done though as it probably blew up trying to keep up with a Honda or Aprilia
I thought this was interesting.
The R0.5 Minimono (half an R1 - geddit??) came together after a deal was brokered with Yamaha Europe to supply a YZ426 engine - the Japanese giant’s Euro-HQ in Amsterdam is full of people interested in Supermono racing, and the chance to see how the firm’s new generation of ground-breaking off-road four-strokes would perform on tarmac, has been an unanswered question many of them were eager to resolve. Dave Pearce initially planned to match this motor up with a TZ125 chassis sourced from his fomer race mechanic Katsuaki Umemoto, who today runs Tigcraft Japan - but opted instead to design his own Tigcraft tubular steel frame for the bike while retaining the Yamaha suspension, because of the vibration and extra stresses which a heavier, torquier fourstroke engine would impose on the 125 GP bike’s aluminium Deltabox chassis, typified by the fact that it broke the TZ125 cushdrive the first time they tried to bumpstart it!
Chassis geometry is the same as the TZ125 which inspired the bike, with a 22-degree head angle and just 82mm of trail from the 35mm Kayaba upside down forks, which retain the same springs as on the GP bike they’re sourced from, with only slightly stiffer damping settings. The GP racer’s aluminium swingarm is also retained, pivoting in the vertically-split engine cases and working a Dutch-made TechnoFlex shock via the stock TZ125 rising-rate link. "The shock is exactly as supplied for a 125 GP road racer, but with 25% more rebound damping, which we’ve found seems to suit big-pistoned singles better," says Dave Pearce. Fitted with RS125 Honda polycarb bodywork, but a special aluminium Tigcraft fuel tank reflecting the greater bulk of the four-stroke engine, the R0.5 Minimono weighs in at just 88 kg. with oil and water, but no fuel - a figure achieved without the use of any titanium, says Pearce, apart from the bolts securing the single 300mm front Braking petal disc, and its 185mm rear counterpart. "It’s important to stress that this is a very low-budget bike," says Dave. "We effectively have no carbon-fibre or titanium in it at all, and it’s been designed to readily accept the running gear from any Honda RS125R or Yamaha TZ125. It’s hard to over-emphasise how completely different the Minimono is to ride compared to the Gallina or another of the big 700cc-plus singles - though ironically it does share quite a lot in common in terms of technique and riding style with a Ducati Supermono. That’s because the key to redressing La Ducatina’s horsepower and weight disadvantages compared to the maxi-singles has always been to exploit its sweet handling and extreme 54/46% frontal weight bias (thanks to the horizontal cylinder’s heavy desmo head) to maintain corner speed and keep up momentum. The R0.5 has the same weight distribution, and asks you to ride it the same way, making the guff about the danger posed by conflicting lines through corners from little and large,
http://www.designdatamanager.com/sco.../mainbody.html
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