<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>That’s reversion which is exhaust pulses running back up through the exhaust & back through the motor.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Weber carbies do not like cams with less than 110 degree cam lob centers for that reason.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Is there more fuel present at the filter now than before ? Without the tail pipe you are missing out<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>on some amount of extraction. Greg Solow has done a ton of dyno work with exhaust systems<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>and he found that an 18”, slight megaphone shape, was superior to just a straight pipe for HP <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>and it’s ability to extract so exhaust coming straight out of a muffler cannot be good and will<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>affect how the entire system performs.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Jim g<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> Fot [mailto:fot-bounces@autox.team.net] <b>On Behalf Of </b>Duncan Charlton<br><b>Sent:</b> Sunday, October 16, 2016 8:07 AM<br><b>To:</b> D V <explore8@outlook.com><br><b>Cc:</b> fot@autox.team.net<br><b>Subject:</b> Re: [Fot] Stutter at 4K rpm<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Derek,<o:p></o:p></p><div><p class=MsoNormal>I’m not sure the fuel in that location tells you much. With some carbs you can see a fuel/air fog standing in the trumpets and this can condense and be visible as droplets when you have the engine stopped.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>Duncan Charlton<o:p></o:p></p></div><div><p class=MsoNormal>Elgin, Texas USA<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal><o:p> </o:p></p><div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal>On Oct 15, 2016, at 10:51 PM, D V <<a href="mailto:explore8@outlook.com">explore8@outlook.com</a>> wrote:<o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p><div><div><div><div><p class=MsoNormal>Thanks everyone for the replies. I will inspect the pipe to manifold and manifold to head to see if anything is loose or any leaks apparent in the morning.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I actually went down a main jet 145 to 140 and that seemed like it helped some but didn't clear up the issue (which is going leaner; opposite of what Greg said). <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>It is missing and backfiring when I am full on the gas. I can prevent it by easing into the gas.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I did notice some gas at my air cleaner to velocity stack connection. I wonder if it is a float issue?<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><br>Sent from my iPhone<o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><br>On Oct 15, 2016, at 7:35 PM, Greg Blake <<a href="mailto:gblake58tr3@icloud.com">gblake58tr3@icloud.com</a>> wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><p class=MsoNormal>Don't know if my other email made it to you. Backfires on deceleration can be a lean condition. Have you checked your plugs? Maybe something got "adjusted" with the bump. <br><br>Sent from my iPhone<o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><br>On Oct 15, 2016, at 12:27 PM, D V <<a href="mailto:explore8@outlook.com">explore8@outlook.com</a>> wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><p class=MsoNormal><br><br>Sent from my iPhone<o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><br>Begin forwarded message:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal style='margin-bottom:12.0pt'><b>From:</b> <<a href="mailto:explore8@outlook.com">explore8@outlook.com</a>><br><b>Date:</b> October 15, 2016 at 10:30:51 AM CDT<br><b>To:</b> <<a href="mailto:fot@autox.team.net">fot@autox.team.net</a>><br><b>Subject:</b> <b>Stutter at 4K rpm</b><o:p></o:p></p></div></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal>Two races ago I went off track and bent my exhaust pipe enough to break the welded joint near the muffler. In the interest of time, I cut the exhaust at the muffler and secured the pipe to the frame.<br><br>At the last race, I noticed the car would backfire at deceleration which I am not surprised but I also noticed a stutter around 4-5k rpm. <br><br>At NOLA this weekend it is more pronounced and comes in when shifting hard from 3rd to 4th. After 5k, it clears up and pulls normally.<br><br>It doesn't seem to be affected by turns and more related to full throttle vs easing into the gas.<br><br>Backpressure from the loss of muffler or unrelated issues?<br><br>1300 spitfire with single Weber 40.<br><br>Sent from my iPhone<o:p></o:p></p></div></blockquote></div></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal style='margin-bottom:12.0pt'>_______________________________________________<br><a href="mailto:fot@autox.team.net">fot@autox.team.net</a><br><br><a href="http://www.fot-racing.com/">http://www.fot-racing.com</a><br><br>Donate: <a href="http://www.team.net/donate.html">http://www.team.net/donate.html</a><br>Archive: <a href="http://www.team.net/archive">http://www.team.net/archive</a><br>Forums: <a href="http://www.team.net/forums">http://www.team.net/forums</a><br>Unsubscribe/Manage: <a href="http://autox.team.net/mailman/options/fot/gblake58tr3@icloud.com">http://autox.team.net/mailman/options/fot/gblake58tr3@icloud.com</a><br><br><o:p></o:p></p></div></blockquote></div></blockquote></div></div><p class=MsoNormal style='margin-bottom:12.0pt'>_______________________________________________<br><a href="mailto:fot@autox.team.net">fot@autox.team.net</a><br><br><a href="http://www.fot-racing.com">http://www.fot-racing.com</a><br><br>Donate: <a href="http://www.team.net/donate.html">http://www.team.net/donate.html</a><br>Archive: <a href="http://www.team.net/archive">http://www.team.net/archive</a><br>Forums: <a href="http://www.team.net/forums">http://www.team.net/forums</a><br>Unsubscribe/Manage: <a href="http://autox.team.net/mailman/options/fot/duncan.charlton54@gmail.com">http://autox.team.net/mailman/options/fot/duncan.charlton54@gmail.com</a><br><br><o:p></o:p></p></div></blockquote></div><p class=MsoNormal><o:p> </o:p></p></div></div></body></html>