If this isn't a fail, i don't know what is. It turns out the gasket in between the cylinder and the block was actually covering up about half of one of the transfer ports. Is it just me, or are manufacturers skimping on easy things to fix? And everywhere else on my grande looks pretty well done. weird. anybody else have stupid little issues like this?
It's probably not a stock base gasket... But maybe that's one way Vespa restricts the top speed?
i bought a polini kit for my garelli a few monthes ago and case matched it. when i went to install the cylinder with the base gasket that came with the kit i noticed it covered a bit of the transfer. i cut the portion that was covering and it's all good, but i too was puzled at how the gasket that came with the kit would cover part of the transfers on the kit...o well.
Always match your gaskets, even from the factory they overlap the ports some on many bikes.
yeah, i matched it before i replaced it. i had to open it up even more because i removed a bit of material on the cylinder and the block. The port matching isn't perfect, but its pretty close. much closer than it was before (besides the gasket). however, even with the widened exhaust port, and port matched and widened transfer ports and the trimmed gasket, i didn't notice any performance gain. i mean really like, nothing. Do you think i did something with that ever important to 2-stroke flow? i didn't do anything extreme at all.
Sometimes these types of minor tuning tips don't amount to much on the seat-of-the-pants-dyno, especially w/o some sensitive carb/jetting mods. Weather (temp and humidity) can play as big of a role from day to day. Although, they probably would show up on a flow bench and they make us feel better knowing that it is as good as it can be.
up jet you have better flow so now you need to jet.
Yeah, i just mounted my polini mod. country exhaust too, so i have to up jet anyways.
i just took it out for a quick ride and man the powerband on this thing is high!
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