Vespa Mazzachelli Race Crank - Stroke ?

[paulnobodyimportant]

I had the above fitted to a P200 engine for a 210 mallosi kit. Now need to know stroke and rod length. From googling, looks like it could be 60 stroke & 110 rod. Without taking crank out, have I guessed correctly as a standard crank has a 58 stroke.

[hungdog]

They come in both 58 and 60mm

[rosscla]

Worth asking whoever fitted it?

[Muttley McLadd]

Aren't standard stroke cranks 57mm?

[hobospeed]

Pop the head off (takes less than 5 minutes on a large frame) and measure the distance between BTC and TDC. I take it you didn't build the motor? Does it run OK and have proper squish (1-1.5mm)? Does it have a cylinder packing plate and/or a thicker than normal head gasket? If so it's a good indication that it's running a 60 mm stroke crank.

Good luck,

Tim

[paulnobodyimportant]

Thanks for your replies and will measure BTC and TDC tonight, which I did think about, as well as a night of dreams of looking for details of the crank. In one dream, the crank spec turned up on the back of a packet of cat biscuits, which seemed rational at the time!!!

Just to clarify matters, the engine was originally build by Buzzsolomoto back in 2009/10. However, its now out of the scooter and on my bench for a winter strip down, including replacing the clutch side oil seal. In the meantime, I've sent my Malossi barrel and piston of to be tweaked and tuned, more for torque than speed. At the time, they didn't want my crank. However, to correctly map out everything, they need to know the above request, but by this weekend, I built up the engine minus the top end and fairly reluctant to undo it all again.

Fortunately, I have a spare and identical Malossi barrel and piston and the original base gasket, so tonight I will fit and measure as hobospeed suggests.



Paul

[paulnobodyimportant]

And the winner is 57mm.

[hobospeed]

Let us know what tweaks are done to the barrel (photos!) and how it turns out.

Tim

[paulnobodyimportant]

Will do and take photos of unmolested Malossi barrel alongside tweaked one. If it seems ok then Monza & TS1 barrel next. Its more a case of blue printing ports and gaining torque rather than a sharp peak power.

This is the local chap whose tweaks two of my Pals TS1 barrels to great effect and is local.
http://mickabbeytuning.co.uk/