Vespa 21t clutch cog

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Jack221
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Sounds like a good set up. If he has not raised the transfer ports, I would hope the base packer is at least 2mm, minimum. The ports in the standard P2 barrel are way to low (on a 57 crank) for high rpm power.
HB should have told you to check for an exact measurment from the piston at TDC to the top of the barrel. And add some base gaskets to the packer, if it was too small. Just 0.1mm will make a big differance to the transfer ports at higher rpm, with only a little adverse affect on the compression.
Did you check the squish clearance after you put the head on? This will show how much you have to play with.
Vespa est ieiunas, quia semper operaturi
johnny rotten
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No mention was made about tdc measurement n when I asked about squish he mentioned not to bother I believe the packer is 1.5mm thick n I have 1 base gasket under the barrel with it
Jack221
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He really should have told you the TDC measurement, the same barrel from one engine to the next could vary by +/- 0.5 mm. Which is a range of 4 degrees on the transfer ports. When looking for maximum performance this is important to know. All the care an attention of grinding out the ports to exact sizes is lost if the barrel is sitting 0.5mm off from its design.
Vespa est ieiunas, quia semper operaturi
johnny rotten
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What where you going to suggest doing if these measurements where obtained?
Jack221
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All I am saying is when the barrel was fitted it wasn't adjusted to any measurement. Just fitted and hope it's ok. As it is, it sounds like it goes well so probably about right anyway but even if it is just 0.1mm off to HB's design it will make a slight difference to the power delivery. As with ignition timing a few degrees on the transfer timing is a lot. When looking for more power this is the kind of place that it is found :)
Vespa est ieiunas, quia semper operaturi
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