Re: Epic Vespa Thread

> - Joe - wrote:

> -------------------------------------------------------

> My dad was asking if we could make his si quieter so I rolled a pipe

> with the proma circuit dimensions but with a side bleed. It has a weird

> powerband where it feels like it hits twice.

That's super cool, I was just thinking about that the other day but with Leo Vince dimensions.

When stuff is so curvey like that I wonder about the length, did you just make a line down the center of the bend? I wonder if the real effective tuned length would actually end up being shorter like 2/3 of the bend rather than down the center?

Re: Epic Vespa Thread

I used these dimensions I’m unsure how accurate they are.

C26E4B2F-C54D-404A-B4AA-A4531F0BE518.jpeg

Re: Epic Vespa Thread

Oh wow that's awesome, never seen that before, I have the puch proma and leovince, and a Vespa proma, I could compare... Certainly I would before putting the time into making a whole pipe

Re: Epic Vespa Thread

That’s probably the better way to go about it, I made 2 sets of these proma spec cones so I could make one for my grande as well but never finished welding that pipe together.

Re: Epic Vespa Thread

Ike Pipe /
1ke OP

@Dewey

Those are amazing! Very cool! That quad is nuts!

Re: Epic Vespa Thread

Dewey Martian /

Built this little scrap parts bike last summer. Super fun to ride

IMG_20211009_220327.jpg

Re: Epic Vespa Thread

It may be a bit of a long shot but does anyone have experience tuning the slide of a 15-16mm SHA on Polini speed engine speed case with a 46mm kit?

I'm having trouble with the bike bogging down in the low end because I'm way to rich there. I've got a 12 (plastic) slanted slide in there right now but that doesn't seem to be doing it. I also have a flat metal one that I can experiment with but I thought I'd ask around first before doing so.

I'm aware I'm going to grind a steeper angle on it but I figured there's no harm in asking.

I've also been thinking of recreating a slide in some CAD software and printing one kind of like the one available on Treatland. I'm not American though so straight up ordering one from there's isn't really an option.

Re: Epic Vespa Thread

Ike Pipe /
1ke OP

Hey Nick

Here's a link to the wiki that talks about slide tuning.

SHA

Hope it helps! I'm glad to see you using a bigger carb on the speed cases. I don't really understand why people stay with the 13.13 when other options are available on those cases.

Re: Epic Vespa Thread

Dirty30 Dillon /

Because 13.13 and 46mm is so much damn fun.

Re: Epic Vespa Thread

yea a 13:13 and a 43mm kit, also fun

Re: Epic Vespa Thread

Ike Pipe /
1ke OP

But why is a 13.13 better than a 16.16 or 18mm Phbg?

Re: Epic Vespa Thread

Dirty30 Dillon /

> Ike Pipe wrote:

> -------------------------------------------------------

> But why is a 13.13 better than a 16.16 or 18mm Phbg?

Better economy; increased low end response; better pulse metering; fits in subframe better and allows use of airbox without limiting belt tensioner travel.

Also: not every bike requires a big carb. Especially rotary induction where intake timing is strictly metered anyways.

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