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Re: [Fot] Stutter at 4K rpm

To: D V <explore8@outlook.com>
Subject: Re: [Fot] Stutter at 4K rpm
From: Duncan Charlton <duncan.charlton54@gmail.com>
Date: Mon, 17 Oct 2016 09:41:35 -0500
Cc: "fot@autox.team.net" <fot@autox.team.net>
Delivered-to: mharc@autox.team.net
Delivered-to: fot@autox.team.net
References: <BN6PR11MB1827DCC65FF9A17E9273C0469DDE0@BN6PR11MB1827.namprd11.prod.outlook.com> <BN6PR11MB1827440A226AEB6F6B9E3AFD9DDE0@BN6PR11MB1827.namprd11.prod.outlook.com> <C90CBE3B-C7EF-4447-9D84-B2574E69E079@icloud.com> <BN6PR11MB182770A8760ED5FE953230B39DD10@BN6PR11MB1827.namprd11.prod.outlook.com> <jmvnicyv499d7oamq1abktat.1476645703577@email.android.com> <BN6PR11MB1827C2DDBD4717811DC599529DD00@BN6PR11MB1827.namprd11.prod.outlook.com>
Derek,

One final thought.  Is the carb mounted with a Weber O-ring type mount with 
Thackeray (helical spring) washers and lock nuts?  On the TR motor the fuel can 
aerate due to vibrations, so if you have it hard-mounted perhaps thereâ??s a 
harmonic vibration around 4000 rpm that could be causing this.  But â?? that 
seems unlikely since it only began after the off that damaged your exhaust.

Duncan Charlton
Elgin, Texas USA



> On Oct 16, 2016, at 10:14 PM, D V <explore8@outlook.com> wrote:
> 
> Thanks again everyone. I checked the header to head and the exhaust to header 
> connection and everything seemed tight. However I went 2 off hard at turn 4 
> this morning and my strap that was holding the exhaust is now mostly gone. I 
> never figured out that 180 degree off camber turn all weekend.
> 
> To answer Scott's question, yes. I can brake downshift to 3rd in a turn. Full 
> on the gas out of the turn and it stutters between 4-5k. If I do the same and 
> ease into the gas I can most of the time keep it steady.
> 
> Re working the exhaust system as well as checking the float will be added to 
> my winter maintenance. 
> 
> Sent from my iPhone
> 
>> On Oct 16, 2016, at 2:21 PM, Barr, Scott <sbarr@McCarty-Law.com> wrote:
>> 
>> Is it temporary?  Just as you get on the gas out of a corner and then clears 
>> up as the revs rise?
>> 
>> If so, do you have no oil in your dashpots or have you removed the dashpot 
>> pistons?
>> 
>> Scott (B.)
>> 
>> 
>> 
>> 
>> 
>> -------- Original message --------
>> From: D V <explore8@outlook.com>
>> Date: 10/16/16 12:53 AM (GMT-06:00)
>> To: Greg Blake <gblake58tr3@icloud.com>, fot@autox.team.net
>> Subject: Re: [Fot] Fwd: Stutter at 4K rpm
>> 
>> 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.
>> 
>> 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).
>> 
>> It is missing and backfiring when I am full on the gas. I can prevent it by 
>> easing into the gas.
>> 
>> I did notice some gas at my air cleaner to velocity stack connection. I 
>> wonder if it is a float issue?
>> 
>> 
>> Sent from my iPhone
>> 
>> On Oct 15, 2016, at 7:35 PM, Greg Blake 
>> <gblake58tr3@icloud.com<mailto:gblake58tr3@icloud.com>> wrote:
>> 
>> 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.
>> 
>> Sent from my iPhone
>> 
>> On Oct 15, 2016, at 12:27 PM, D V 
>> <explore8@outlook.com<mailto:explore8@outlook.com>> wrote:
>> 
>> 
>> 
>> Sent from my iPhone
>> 
>> Begin forwarded message:
>> 
>> From: <explore8@outlook.com<mailto:explore8@outlook.com>>
>> Date: October 15, 2016 at 10:30:51 AM CDT
>> To: <fot@autox.team.net<mailto:fot@autox.team.net>>
>> Subject: Stutter at 4K rpm
>> 
>> 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.
>> 
>> 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.
>> 
>> 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.
>> 
>> It doesn't seem to be affected by turns and more related to full throttle vs 
>> easing into the gas.
>> 
>> Backpressure from the loss of muffler or unrelated issues?
>> 
>> 1300 spitfire with single Weber 40.
>> 
>> Sent from my iPhone
>> _______________________________________________
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>> 
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