[TR] 61 TR3A SU H6 Carb Issues

Tue Oct 16 13:45:12 MDT 2018

..agreed   :-)     but..   (gotta' throw in on caveat)
they will perform the same...IF all cyls are performing the same .... 
variations the meters don't respond to
EG: valve sealing, compression, ring blow by all dismissed as 'noise' 
via the cross port in the manifold.

Just wondering...  Q for the crowd at large.... does anyone still use  
the little rods in the tops of their carbs for balancing?
(usually little kits with a jet wrench and etc)

v/r

ptegler

On 10/16/2018 12:58 PM, DAVID MASSEY wrote:
> First off, let me say that if you don't have a flow meter, using the 
> hose/listening method works well enough for our primitive engines.  
> But the meter will provide greater accuracy.  Sure putting the airflow 
> meter effects the flow through the carb (a bit) but we are not trying 
> to get an absolute calibration.  We want a relative calibration and if 
> both carbs behave the same with the flow meter in place they are set 
> the same.  And that is the end result desired.
>
> Dave Massey
>
>
>
> -----Original Message-----
> From: ptegler <ptegler at verizon.net>
> To: dave1massey <dave1massey at cs.com>; trguy75 <trguy75 at gmail.com>; 
> triumphs <triumphs at autox.team.net>
> Sent: Tue, Oct 16, 2018 11:27 am
> Subject: Re: [TR] 61 TR3A SU H6 Carb Issues
>
> agreed.... especially considering that no one stated the human ear was 
> 'better' than an instrument. BUT.....
> Take a look at any procedure for multiple carbs (greater than two)   
> EG: quads on a bike or 8/12 carbs on a Ferrari. ...even three DCOEs on 
> a Triumph 6
> NONE suggest a flow meter blocking the intake.  On most bike engines 
> you use multiple water columns via taps on the sides of the carbs 
> specifically designed to facilitate balancing. Compared to most LBC's 
> none have a balance port in the intake manifold so no 'cross 
> contamination ' from air flow via another carb. Block one of four bike 
> carbs and the engine will slow very noticeably.
>
> sure the 'premise' is you block both carbs (one at a time) but neither 
> is 'as is' when running. When you place the meter over the carb throat 
> you change the depression and running position of the piston in the 
> throat.  Air volume vs velocity is changed...effecting the carb 
> operations, both air AND fuel.  when you slow down the air velocity it 
> doesn't pull as much fuel, and starts consuming air from the other 
> carb via the balance port in the manifold etc etc.
>
> You need to use whatever method best suites your sensibilities. As too 
> the repercussions of you procedures. Each case is different, each case 
> has different expediencies, habits and results   :-)
>
> ptegler
>
>
>
> -----Original Message-----
> From: DAVID MASSEY <dave1massey at cs.com>
> To: ptegler <ptegler at verizon.net>; trguy75 <trguy75 at gmail.com>; 
> triumphs <triumphs at autox.team.net>
> Sent: Tue, Oct 16, 2018 7:34 am
> Subject: Re: [TR] 61 TR3A SU H6 Carb Issues
>
>
>     Seriously though.... what method didyou use to balance the air
>     flow at idle? One of those little flow meters?
>     NOPE NADA STOP right there.   Think about it...you're sealing off
>     the air to get the bubble to rise so of course the idle
>     changes....so the balance tube in the manifold sucks from the
>     other carb, bypassing the fuel pull.
>
>
> What are you talking about?  Sure you affect airflow with the airflow 
> meter but you are affecting both carbs equally when you switch from 
> carb to carb.  If you get the same reading from both they are being 
> effected the same and have the same starting point.  The concept that 
> the human ear is better than an instrument specifically designed to 
> measure airflow is pure hubris.
>
> One thing to watch out for is assuming that since the carbs are 
> balanced at idle they are balanced under throttle.  Be very careful 
> when tightening down the linkage to ensure that both carbs open 
> simultaneously.  This is particularly important on the TR6-style 
> linkage that has built-in disengagement zones.
>
>
> Dave Massey
>
>
>
> -----Original Message-----
> From: Paul Tegler <ptegler at verizon.net>
> To: Jim Henningsen <trguy75 at gmail.com>; triumphs <triumphs at autox.team.net>
> Sent: Tue, Oct 16, 2018 3:16 am
> Subject: Re: [TR] 61 TR3A SU H6 Carb Issues
>
> ok....what do you mean by 'carbs aren't running smoothly'  ?
> Engine is not smooth?.. sputtering? not running smooth while cruising?
> An old adage.... (well two actually)
> "..most carb problems are electrical..." and "..most ignition problems 
> are the carbs"
> Seriously though.... what method didyou use to balance the air flow at 
> idle? One of those little flow meters?
> NOPE NADA STOP right there.   Think about it...you're sealing off the 
> air to get the bubble to rise so of course the idle changes....so the 
> balance tube in the manifold sucks from the other carb, bypassing the 
> fuel pull.
> I was finally convinced by an old mechanic and have learned from 
> tuning more SU and ZS carbs than I care to mention.... use a 1/4" fuel 
> line as a stethoscope ...one end in your ear..the other just up 
> against the edge (not in) the carb throat. blocks minimal air... and 
> believe me you can hear as little 1-2 cfm readily, but you can also 
> hear the gurgle of the fuel flow!   Years ago I actually gave away my 
> flow gauges.
> Eons ago..I got so fed up once I bought brand new NOS SU carbs to 
> replace mine after three rebuilds of the orig units. BUT...STILL had 
> the same issue...smooth speed cruising and it ran like crap. Pull the 
> choke out and it ran fine, but had to push it in at closed or low 
> speed throttle. Spent a year+ and hundreds of messages on various LBC 
> lists....still to no avail.  Than one day at a car show.... I saw a 
> guy with an identical setup.... open big round K&Ns and a end plate 
> but had his air filters nearly 3/4 closed off with duct tape.  In the 
> end, the problem was incorrect vacuum effects ...not enough air 
> velocity when the piston was mid/down as there was no restriction from 
> the air filters.
> hhmmm.... ok...
> http://www.teglerizer.com/mgstuff/a_stumble_at_cruise.htm
>
>
> ptegler
>
>
> On 10/15/2018 7:40 PM, Jim Henningsen wrote:
>
>     Ok, I thought I had this rebuild all nailed down.  Finally got around to
>     getting carbs balanced and set for correct mixture.  After new kits, testing
>     piston drop timing per John Twist you tube clip (great clip), and spending
>     two hours fine tuning air flow and mixture.  The carbs aren't running
>     smoothly.  There is something not right and I am throwing in the towel.
>     Don't have a reliable mechanic that I trust for this in Ocala.  Any
>     recommendations on a rebuilder to send these two to have them checked
>     professionally.
>
>     Joe Curto?
>     Jeff Payla at Paltech - cant seem to get a response from him.
>     Buy new (ouch)
>     Others?
>
>     Thanks in advance
>     Jim Henningsen
>     Ocala FL
>     61 TR3A  eager to enjoy driving it in fall in Florida
>     62 TR4 eager to have restoration finished
>     75 TR6 eager to have new race motor put in
>     82 Jeep ld reliable - get in and go
>     2002 Triumph Trophy 1200 eager to just get out and be used.
>        
>
>     **triumphs at autox.team.net  **
>
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>
> -- 
> Paul Tegler
> ptegler at verizon.net   www.teglerizer.com
>
>

-- 
Paul Tegler
ptegler at verizon.net  www.teglerizer.com

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