Like in the good old days at Piaggio, the bgm PRO crankshafts are forged. The forging process...Continue reading
Like in the good old days at Piaggio, the bgm PRO crankshafts are forged. The forging process gives a much higher density to the material. So you gain a better thermal coefficient and a much stronger material. Like known from the WIESCO pistons.
Beside the crank webs the con rod is forged as well and afterwards CNC finished.
There is no doubt about the lubrication and bearings of the crankshaft. The lubrication of the big end pin is by two large slots and four additional pockets at the side. The SSC racing bearing and the two fat shims make it a very solid construction.
For the lubrication of the small end bearing there are two holes at the small end. The delivery contains a INA small end bearing.
The crankshaft is available with longer stroke 60 mm and standard stroke 57 mm. The long stroke gives not just more cc, it enables you to set the port timings of the transfers and exhaust more freely. Give us a call or sent us an email for the perfect match of crankshaft and cylinder kit.
The bgm PRO Racing crankshaft has a much better inlet design than any other crankshaft:
The inlet timing of the standard crankshaft is not suitable for tuning purposes. The timing is too short and once you reach a certain amount of revs, the inlet timing will close off.
The commonly available Racing crankshafts do have longer inlet timing, but the inlet is opened too long after top dead centre. A massive engineering problem that gives heavily blowback, bad low down and mid range power and hard to set up carbs.
The bgm PRO crankshafts is closed after 65° after top dead centre. Something we figured out with heavily dyno and road testing. With the bgm crank the set up of the engine is as easy as if an OEM Piaggio crank is fitted. The improved timings are capable of working with fully tuned Polini or Malossi set ups. Even with the tiny SI carb power figures of more than 20 hp at the rear wheel are easily to achieve.
UPSHOT:All in all every single detail of the bgm PRO crankshaft is spot on. Machining, materials, balancing and the engineering leave nothing to be desired.
Techtipp:Another bgm design gimmick of the crank is that you can fit the Gilera Runner oil seal as an option. The 24x35x7 can be used on the flywheel side. It is stronger, double lipped and made from Viton.