X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ispmxmta05-srv.windstream.net ([166.102.165.166] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTP id 2189331 for flyrotary@lancaironline.net; Fri, 20 Jul 2007 09:51:48 -0400 Received-SPF: pass receiver=logan.com; client-ip=166.102.165.166; envelope-from=montyr2157@alltel.net Received: from ispmxaamta08-gx.windstream.net ([216.96.20.30]) by ispmxmta05-srv.windstream.net with ESMTP id <20070720135102.ZVOR7621.ispmxmta05-srv.windstream.net@ispmxaamta08-gx.windstream.net> for ; Fri, 20 Jul 2007 08:51:02 -0500 Received: from Thorstwin ([216.96.20.30]) by ispmxaamta08-gx.windstream.net with SMTP id <20070720135102.NTZW16279.ispmxaamta08-gx.windstream.net@Thorstwin> for ; Fri, 20 Jul 2007 08:51:02 -0500 Message-ID: <003901c7cad5$07a99eb0$6501a8c0@Thorstwin> From: "M Roberts" To: "Rotary motors in aircraft" Subject: Carbs Date: Fri, 20 Jul 2007 08:51:10 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0036_01C7CAAB.1EA64520" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0036_01C7CAAB.1EA64520 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I'm using 44mm mikuni round slide motorcycle carbs. I think they cost me = about $150 on Ebay.=20 They have a mixture enrichment for cold start that is nothing more than = a fixed jet that a cable actuated plunger opens up, with an emulsion = tube to help vaporize the fuel. Not really any good for mixture = adjustment. Since the float bowl vents are plumbed to fittings, you can just use a = needle valve between the venturi vacuum and the float vent to control = mixture.=20 You just plumb a tube to the float vent, a tube to the venturi, and a = tube to ambient. You T the lines and put the needle valve on the venturi = leg of the T. Put a restrictor orifice in the ambient line. The way this = works is to change the pressure between the float bowl and venturi. If = they are the same no fuel will flow. If the float bowl is higher = pressure, fuel is forced into the venturi.=20 You set the main jet for WOT cold day SL power. The needle valve can = then adjust for anything from SL conditions to lean cut off. Monty ------=_NextPart_000_0036_01C7CAAB.1EA64520 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I'm using 44mm mikuni round slide = motorcycle carbs.=20 I think they cost me about $150 on Ebay.
 
They have a mixture enrichment for cold = start that=20 is nothing more than a fixed jet that a cable actuated plunger opens up, = with an=20 emulsion tube to help vaporize the fuel. Not really any good for mixture = adjustment.
 
Since the float bowl vents are plumbed = to fittings,=20 you can just use a needle valve between the venturi vacuum and the float = vent to=20 control mixture.
 
You just plumb a tube to the float = vent, a tube to=20 the venturi, and a tube to ambient. You T the lines and put the needle = valve on=20 the venturi leg of the T. Put a restrictor orifice in the ambient line. = The way=20 this works is to change the pressure between the float bowl and venturi. = If they=20 are the same no fuel will flow. If the float bowl is higher pressure, = fuel is=20 forced into the venturi.
 
You set the main jet for WOT cold day = SL power. The=20 needle valve can then adjust for anything from SL conditions to lean cut = off.
 
 
Monty
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