Project Varatrackerstorm or Firetrackerdero.

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Varastorm
Posts: 1150
Joined: Mon Apr 07, 2014 11:48 pm
Location: Isle of Anglesey

Re: Project Varatrackerstorm or Firetrackerdero.

Post by Varastorm »

sirch345 wrote: Sat Oct 28, 2017 9:19 pm If you go for the Vance and Hines look, just remember to build in some heat protetction for your right leg :)

Chris.
The carb filter will be acting as a guard Chris, my knee touches it.

As for the heat under my right leg/ass I don't know. I suppose the real deal flat trackers were only designed for short races.

If this exhaust does go high level I might have to go double underpants style :eek2 :thumbup:
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sirch345
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Location: The West Country.

Re: Project Varatrackerstorm or Firetrackerdero.

Post by sirch345 »

Varastorm wrote: Sun Oct 29, 2017 8:26 am
sirch345 wrote: Sat Oct 28, 2017 9:19 pm If you go for the Vance and Hines look, just remember to build in some heat protetction for your right leg :)

Chris.
The carb filter will be acting as a guard Chris, my knee touches it.

As for the heat under my right leg/ass I don't know. I suppose the real deal flat trackers were only designed for short races.

If this exhaust does go high level I might have to go double underpants style :eek2 :thumbup:
You could probably find fireproof undies :lol:

Chris.
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kenmoore
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by kenmoore »

Hey Vara,

Any progress on the beast?
South Coast
New South Wales
Australia
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Varastorm
Posts: 1150
Joined: Mon Apr 07, 2014 11:48 pm
Location: Isle of Anglesey

Re: Project Varatrackerstorm or Firetrackerdero.

Post by Varastorm »

Hi Kenmoore, I've not touched it tbh :(

Firstly, my car failed on me, it's a 260000 mile Audi A6, blown turbo pipe which has caused the turbo to fail..

I emergency bought a Lupo 1.0 :lol: I'm getting 50mpg, that's 20mpg more than the Varadero 8O

Now I've been roped into building a kitchen for my daughter :roll:

Hopefully I'll sort something out in December, maybe persuade the troops to buy me the bits for that exhaust I've built in my head.

I'll mention it for a Christmas prezzie :thumbup:

Weber info added for future reference :thumbup:
weber tuning guide

Postby gen mk 1rs2000 » Fri Oct 28, 2011 9:02 pm

i had this sent to me
some usefull reading ??


Subject: Weber carburettor tuning and formula required correct jetting for Ford Escort 2.0 Pinto engines etc.



Selection and tuning of Weber DCOE carburettors

By D V Andrews – UK

A very popular modification for RH7 owners is the fitment of twin Weber DCOE or DCO/SP

carburettors; these not only deliver the goods but also look very good. A good deal of mystique

surrounds Webers, specifically Weber jetting and tuning. However Weber DCO series carbs are

not as complicated as you might imagine, and whereas there is no substitute for a good rolling

road session to tune them, there is much you can do to tune them yourself, by selecting the

correct choke sizes and initial jet settings according to a fairly simple set of rules. This should get

the engine running to a reasonable standard in preparation for the rolling road.

Arriving at the correct carb/venturi size

When selecting Webers, the most commonly asked question is "Should I have 40s or 45s"

coupled with "Surely the 45s will give more power". This shows a basic misunderstanding of the

construction and principles of operation of the DCO series. It is not the barrel size (40 or 45) which

determines the airflow and therefore potential horsepower; it is the size of the main venturi or

choke. Selection of the correct main venturi size is the first step in selecting the carburettor.

It is easy to make the assumption that biggest is best when selecting a main venturi size, but the

purpose of the main venturi is to increase the vacuum acting on the main jet in order to draw in

and effectively atomise the fuel mixture. The smaller the main venturi, the more effective this

action is, but a smaller venturi will inhibit flow. A large venturi may give more power right at the top

end of the power band, but will give this at the expense of lower RPM tractability. Only a circuit

racer will benefit from this sort of compromise, on a road car, driveability is much more important.

95 percent of the time, a road engine is nowhere near its peak power, but is near its peak torque

for 75 percent of the time. It is much more important therefore to select the main venturi for best

driveability, once the venturi size has been selected, then the appropriate carburettor size can be

arrived at.

Here is a small chart showing the available Main Venturi size for Common DCO series carbs

Size Available Venturi sizes

40 24-36mm

42 24-34mm

45 28-40mm

48 40-42mm

48/50SP 42-46mm

55SP 46-48mm

Below is a chart that will allow the correct selection of main venturi size for engines given the

engines capacity and the RPM at which peak power is realistically expected to be achieved, for

road engines peak power is usually between 5250 and 6500, depending on the cam selection.

After the correct venturi size has been arrived at it is a simple matter to determine whether 40/45

or 48 DCOs are required, take the venturi size and multiply by 1.25, the result is then the ideal

barrel size which will accommodate the venturi size selected.

Chart Showing Main Venturi Sizes for Various Engine sizes and RPM ranges

(For four cylinder cars)

Carburettor Barrel size calculation

Venturi/choke size * 1.25

For example: a two litre engine giving its maximum power at 6000RPM will require a venturi size

of 36mm, and therefore an ideal barrel size of 45mm (36 * 1.25). For this application 45 DCOE is

the ideal solution, however a 40 DCOE will accommodate a 36mm choke, so if funds are limited

and the engine is not going to be tuned further then 40 DCOEs will do the job.

If you have bought your Webers second-hand, it is important to understand that it is unlikely that

they will be 'ready jetted'. However if you do not want the expense of changing the main venturis,

you will still need to know their size, this is normally embossed on the venturi itself, so look

carefully down through the main barrel of the carb from the air cleaner side.

Diagram of Main Jet assembly

Main Jet and Air Corrector Size Selection

A useful formula for the calculation of main jet size when the main venturi size is known is to

multiply the main venturi size by 4. This will give a starting point for the main jet size which should

be 'safe', again as a starting point the emulsion tubes can be selected from the table shown below,

although for Pinto F9 or F16 will generally be OK. If your carbs are already equipped with these,

then that will save you some money. Air corrector jet initial settings should be around 50 higher

than the main jet.

Main jet size Venturi size * 4

Air corrector Main jet size + 50

Using these formulae, a venturi size of 36mm will require a main jet of 145 and an air corrector of

around 190.

Emulsion tube Selection

Below is a table showing suggested emulsion tube type, for a given single cylinder capacity.

Cylinder capacity Suggested tube

250-325 F11

275-400 F15

350-475 F9, F16

450-575 F2

Using the above formulae, the ideal settings for a 2000cc Pinto with power peaking at 6000RPM

(290 degree cam or above) are as follows

36mm chokes

F16 or F2 Emulsion tubes

145 Main jet

190 Air corrector

The 2000cc Pinto in just on the cusp of change for emulsion tube type between F16 and F2, if you

already have F16 tubes, use them it is not worth the expense of change, they will just cause the

main circuit to start marginally earlier. A 2.1 or 2.2 Pinto should however be using F2s although

F16s will do the job acceptably well.

Diagram of Idle Jet Assembly

Idle Jet selection

Idle jets cause a lot of confusion; although their name suggests that they govern the idle mixture,

this is incorrect. It is true that the fuel consumed at idle is drawn through the idle jet, but the idle

mixture is metered not by these jets, but by the idle volume screws mounted on top of each barrel.

The idle jets control the critical off-idle progression between closed throttle and the main jet circuit,

it is this part throttle operation which is so important to smooth progression between closed throttle

and acceleration and for part throttle driving. If this circuit is too weak then the engine will stutter or

nosedive when opening the throttle, too rich and the engine will hunt and surge especially when

hot. The technique for establishing the correct idle jet size is detailed later, but as a starting point

40/45f9 idle jets for a 1600 engine 45/50 f9 for an 1800 and 50/55f9 for a 2000 will get you out of

jail free.

Below is a chart showing approximate idle jet sizes for given engine sizes, this assumes one carb

barrel per inlet port E.G. two DCOEs.

Engine size Idle jet size

1600cc 40/45

1800cc 45/50

2000cc 50/55

2100cc 55/60

Establishing the correct idle jet for a given engine is not easy but usually an approximation will

make the car acceptably driveable. If the progression is weak then the engine will nosedive when

moving the accelerator from smaller to larger throttle openings. A certain amount of change

(richer/weaker) to progression can be achieved by varying the air jet size on the idle jet; this alters

the amount of air that is emulsified with the fuel drawn through the idle jet. If this does not richen

the progression sufficiently then the next jet size up, with the same air bleed should be tried.

Below is a small chart showing the most commonly used air size designations, running from weak

to rich. Generally speaking start your selection with an F9 air bleed.

Weaker Normal Rich

F3 , F1 , F7 , F5 ,F2-F4 ,F13 ,F8-F11-F14,F9 , F12 , F6

The ones in normal use are F2,F8,F9 and F6.

Diagram of DCO type carburettor

Setting the Idle and slow running

Rough running and idle is normally down to the idle mixture and balance settings being incorrect,

below is a technique to establish a clean idle and progression. Before adjusting the carbs in this

manner you must make sure that the following conditions are met.

i) The engine is at normal operating temperature

ii) That the throttle return spring/mechanism is working OK

iii) That the engine has sufficient advance at the idle speed (between 12 and 16 degrees)

iv) That an accurate rev counter is connected.

v) That there are no air leaks or electrical faults.

A reasonable idle speed for a modified engine on Webers is between 900 and 1100 RPM.

If you are adjusting the idle for a set of carbs already fitted then progress to the second stage, if

the carbs are being fitted for the first time, screw all of the idle mixture adjustment screws fully

home and then out 2.5 turns. If you are using DCO/SP carbs then start at one turn out. Start the

engine and let it reach normal operating temperature. This may mean adjusting the idle speed as

the engine warms up. Spitting back through the back of the carburettor normally indicates that the

mixture is too weak, or the timing is hopelessly retarded. If this happens when the engine is warm

and you know that the timing is OK, then the mixture will need trimming richer on that cylinder. Set

the idle as near as you can to 900RPM.

Using an airflow meter or carb synchroniser adjust the balance mechanism between the carbs to

balance the airflow between them, if the rearmost carb is drawing less air than the front, turn the

balance screw in a clockwise direction to correct this. If it is drawing more air, then turn the

balance screw anti-clockwise. If the Idle speed varies at this point, adjust it back to 900 RPM, to

decrease idle speed screw in an anti-clockwise direction, to increase, screw in a clockwise

direction.

When you are sure that the carbs are drawing the same volume of air, visit each idle mixture

screw, turn the screw counter clockwise (richening) in small increments (quarter of a turn),

allowing a good 5 - 10 seconds for the engine to settle after each adjustment. Note whether

engine speed increases or decreases, if it increases continue turning in that direction and

checking for engine speed, then the moment that engine speed starts to fall, back off a quarter of

a turn. If the engine speed goes well over 1000RPM, then trim it down using the idle speed screw,

and re-adjust the idle mixture screw. If engine speed decreases then turn the mixture screw

clockwise (weakening) in small increments, again if engine speed continues to rise, continue in

that direction, then the moment it starts to fall, back off a quarter a turn. The mixture is correct

when a quarter of a turn in either direction causes the engine speed to fall. If that barrel is spitting

back then the mixture is too weak, so start turning in an anti-clockwise direction to richen. During

this procedure, the idle speed may become unacceptably high, so re-adjust it and repeat the

procedure for each carb barrel.

After all the mixture screws have been set, the idle should be fairly even with no discernible

'rocking' of the engine, if the engine is pulsing, spitting or hunting then the mixture screws will need

further adjustment. If the engine is rocking or shaking then the balance is out, so revisit with the

airflow meter/ carb synchroniser. No amount of adjustment will give a good idle if the throttle

spindles are bent or leaking air or the linkages are loose on the spindles!

That’s all there is to it.

Starting technique for Weber equipped engines (engine cold)

Some Webers have a cold start circuit (choke), others don't, in my experience, it is very easy to

flood the engine and wet plugs using the cold start mechanism, as it very crude in operation. The

accepted technique for cold starting is as follows:-

Allow the float chambers to fill if you have an electric pump, this should take about 5-10 seconds,

fully depress the accelerator rapidly four times, then on a light throttle, turn the engine over, if it

does not start immediately, repeat the procedure three times. The engine should fire, but may

need 'nursing' for a minute or two before it will idle, gentle prodding of the accelerator should keep

it alive long enough for it to warm up. If the engine does not fire within three attempts, then try five

or six pumps. If this does not work, depress the accelerator fully and hold it open while turning the

engine over for 5 to 15 seconds, then close the accelerator and try again.

Buying second-hand

When buying Webers second-hand ensure that they are a matched pair. Look carefully at the

serial numbers on the top of the carbs, these should be the same, or very similar. If they are not

then they are not a matched pair and may well give problems when trying to jet them, as the

progression drillings could be different. Inspect the carbs very carefully before parting with your

cash, check their general condition, check for fire/heat damage, check that the butterflies open

and close smoothly and that the linkages are smooth in operation and the carbs don't stick open. A

common problem with Webers is the attachment of the throttle quadrant to the spindle, these can

wear and will give an erratic idle and progression which no amount of tuning will cure. It is

important to note that Webers are very rarely 'ready jetted' so factor the cost of jets etc. when

deciding on your purchase. Check the throttle spindles for wear, excessive wear here will bleed air

into the engine and again will affect setting up dramatically. Servicing kits for Webers are relatively

cheap so a neglected pair, provided that the above checks are carried out, can be restored to very

good condition by a thorough clean and service, the servicing is not difficult but has to be done in

a clean environment, using a methodical approach.

Example Jetting from real applications

Jetting for standard 2000/1800/1600 Pinto on 40s

34mm Chokes

135 main jets

F11 emulsions

190 air correctors

35 pump jets

40/f9 idle jets,45/f9 for 1800/2000

4.5 aux vents

Jetting for modified 1600 Pinto on 40s

34mm chokes

140 main jets

F16 emulsions

190 air correctors

40 pump jets

40/f9 idle jets

4.5 aux vents

Jetting for modified 1800 Pinto on 45s

36mm chokes

140 main jets

F16 emulsions

170 air correctors

40 pump jets

45 f11 idle jets

4.5 aux vents

Jetting for modified 2000/2100 Pinto on 45s

38mm chokes

145 main jets

F16 emulsions

180 air correctors

40 pump jets

50f9 idle jets

4.5 aux vents

Dave Andrews









Triple-Weber DCOE for Triumph TR6/TR250

Webers are often maligned. This is more often due to poor installation by inexperienced and impatient mechanics. Webers are not rocket science, nor do they require that one be an experienced mechanic. What is required is a good deal of common sense, a methodical and patient approach, and some understanding of the air-fuel system and its combustion.

For every owner I have spoken with who have expressed their nightmare with Webers, there are 2-3 owners who have glowing remarks. The only real complaint that can be leveled at Webers is their consumption of fuel (which may be symptomatic of incorrect jetting/valving). Expect 15-18mpg in a TR6 that is driven at a more-than pedestrian pace.

Introduction

Read TerriAnn Wakeman's page on DCOEs for TR2/3.

Terri's article is highly recommended.

Task: To provide an electronic archive of accumulated knowledge of fitting a set of Weber 40 DCOE Webers to Triumph TR250/TR6. Sources include books, email, interviews and web-sites.

Note: All DCOE carbs are not equal. They will often differ in the length of the accelerator pump stroke and pattern of progression holes. The designator is stamped on the casting. Weber recommend the 40 DCOE-18 for Triumph 3/4/250/TR6/GT6, whereas Haynes Techbook suggests that the 40 DCOE-2 is best for TR250/6/GT6 and 42 DCOE-8 for TR2-4. I attempt to explain the reason for this discrepancy in the article below. This little fact is almost completely ignored by most so-called Weber experts. Get this wrong, and you may always have a flat-spot.

Note: The TR6 heads for 1969-73 differ from 1974-75 in intake port size and location. Before you purchase a set of Webers, make sure the intake manifold will match your heads.

40 DCOE jettings and settings for TR250/6

D = choke size
E = auxiliary venturi
F = main jet, controls fuel mixture in the emulsion tube as cruise circuit is activated
G = emulsion tube
H = air corrector jet, affects only performance at high RPM
I = idle jet, affects idle and progression circuit
J = accelerator pump jet
K = accelerator pump inlet valve with exhaust orifice (also called a discharge bleed).
L = needle valve, affects fuel flow into the float bowl

Reference D E F G H I J K L-----------------------------------------------------------Weber (0) 30 4.5 120 F11 160 50/F11 40 50 ? Haynes (0) 27 4.5 130 F2 160 50/F11 45 0 2.00Fitzgerald (0) 27 4.5 120 F11 160 49/F9 60 ? 1.75TriumphTune (0) 28 4.5 115 F16 175 50/F9 35 ? -TriumphTune (0) 30 4.5 125 F16 180 50/F9 35 ? -Phillips 30 4.5 155 F11 200 45/F9 50 ? -C. Kantarjiev 28 4.5 110 F2 160 45/F9 - ? -A. Nugent (1) 28 4.5 120 F16 175 50/F9 35 ? -A. Nugent (2) 30 4.5 120 F16 180 50/F9 35 ? -A. Nugent (3) 33 4.5 125 F16 185 50/F9 40 ? -L. Bickel (4) 28 - 120 F11 160 -/F9 - ? -B. Mains (5) 30 - 120 F11 160 60/F9 50 ? - R. Lang (6) 28 4.5 125 F16 160 55/F12 45 ? -R. Lang (7) 28 4.5 120 F2 165 55/F12 45 ? -S. Ingate (8) 30 - 120 F11 - 50/F11 40 ? -40 DCOE-151 (9) 30 4.5 115 F11 200 45/F9 40 100 1.75S. Ingate (10) 45 C. Arnold (11) 140 F11 160 55F9 (0) See reference list at end of page.

(1,2,3) (Allen Nugent at unsw dot edu dot au, Aug 98)

(4) "... and most important- choke tubes (venturis)- 28mm Disconnect the choke cable- it isn't needed. Make sure that the float level is correct. Also I run 26 degrees total advance on the distributor (10 + 16)." (Larry Bickel, ljbtvr at aol dot com, Apr, 97).

(5) "The cam specs: Intake-Open/Close-36' BTDC/ 69' ABDC Exhaust-72' BBDC/33' ATDC Lift 405 Dur 285..... The multiple spark feature of the MSD 6AL Ignition module made a BIG difference for the fuel richness/plug fouling, .055 spark plug gap for NGK BPR6ES, using standard points/gap and a Lucas Sport coil. Timing is about 28' advanced.......Roller rockers are 1.50:1. Stock exhaust headers and freeflow, dual mufflers. Compression-9.5:1. We tried the 45F9 and 60F8 idle jets but didn't work. Also tried 180 air, F16 emulsion and 125 main jets. Initially had 40 accel pump jets. Again no luck." (Bob Mains, President, Buckeye Triumphs, bob dot mains at ode dot state dot oh dot us, Sept 00) .

(6) Race car, 11:1 compression, Piper 270 symmetrical cam, Monza header, mild porting, stock rockers, steel valve guides. Mallory dual-point dizzy, no spark box. Guesstimate is 150 HP. (Bob Lang, lang at isis dot mit dot edu, Oct 02)

(7) Street car. Had a lot of trouble in the progression circuit, rich at idle. Probably needed better spark control. F2 emulsion tubes better for street driving, and F11 for running Street Prepared (with 125/165 main/air corr.). Guesstimate is 130 HP. (op. cit)

(8) Mild street car. DCOE-18 on car for 17 years, one owner, who was pleased with the way they ran. No other details available (author, Apr 98).

(9) The current model 40 DCOE is the 151 series (made in Spain), and I give its calibration as a means of reference. The 151 series seems to be appearing in "TR6 kits" offered by the big parts vendors and found on the web. Additional calibration material are: progression holes=120/100/100, throttle-plate angle=78 degrees. I'm not sure how well this unit would work "out of the box"; probably not!

(10) Goodparts GP3 cam, 9.5:1 compression, Crane ignition, Grp 44 headers. Stumbled at 1800 rpm, ran rich across the spectrum (author, Jan 03)

(11) Runs a D9 cam, heavily ported head and tuned on a dyno. With a 270 degree cam, ran 120 mains, 160 air (Chuck Arnold, chuck dot arnold at oracle dot com, May 03)



Tuning Techniques

Clearly space precludes and exhaustive treatise. But to summarize, the only thing that a tuner is testing is the mixture strength. One can do this by the "plug cut" method (checking color of the spark plug electrode), or analysing exhaust-gas. Use of an O2 sensor plugged into the exhaust system will certainly help the tuner (K&N make a good system), the best technique has always been the plug cut, conducted either on a dyno, or correctly on the road.

Plug-cut technique
Generally quite simple once a suitable time and place are chosen. Ensure that the correct plugs are being used, and are clean (i.e. new, or near new), with a white insulator.

Hold the RPM at the necessary level in as high a gear as possible for 10 or so seconds
Then, simultaneously, foot off the gas, disengage clutch, ignition off.
Inspect the plug(s), usually one plug for each of the carburettors.
If the plugs are sooty black, then the mixture is too rich. If the color is that of milk chocolate, it is a little to lean. If the color of dark chocolate, then a little too rich. A good reading will have the insulator showing almost white, with just a suspicion of grey, and a plug body on the dark side, just enough to mark a piece of white paper with soot. Further interpretation of plug color can be found elsewhere on the web, but the color to avoid is an even battleship grey on the whole plug, electrode, insulator and body - a sure sign of detonation or pre-ignition (ignition too advanced).

Low- and Mid-RPM Hesitation

This may be the domain of the accelerator pump. As noted above, the 40 DCOE comes in different series, each with a variety of accelerator pump stroke lengths. The series 2, 4, 24, 27, 28, 32, 33 have 14mm stroke lengths, the 18, 22/23, 29/30 have 10mm stroke lengths, the 31, 34/35, 44/45, 76/77 have 16mm stroke lengths, and 72/73, 80/81 have 18mm stroke lengths. The pump stroke rod (which governs stroke length) is interchangeable between series, but must be chosen carefully when combining with the various combinations of accelerator pump jet and pump bleed valve. Most owners have suggested using a blank bleed, which is consistent with the Hatnes recommendations, but this is inconsistent with the Weber recommendation.

The importance of the accelerator pump occurs during rapid transitions to full throttle. When the throttle is opened quickly, the sudden rush of air cuases an increase in pressure in the inlet tract which causes atomized gas particles to condense and fall like rain to the floor of the duct (which will remain there unless the manifold is heated; this lake of fuel is often the reason for Weber fires). All this results in a massive flat spot, and the purpose of the accelerator pump is to fill this hiatus until the main jet can ctach up with the demand. The perceptive reader can now grasp that the long-stroke pumps discharge more gas for a longer duration than the short-stroke pumps. On the other hand, the short-stroke pumps deliver a shorter, more intense "squirt". If the accelerator pump jet is made larger, the duration of delivery will be less. If the spring that controls the r

We are thus we are playing a game of balancing three variables; pump stroke, jest size and bleed size (4 variables if you wish to include pump spring rate), all of which regulate the volume and duration of gas delivery between throttle application and when the main jet can catch up. And of course, we would like the accelerator pump system to discharge no gas when the throttle is kept constant or opened slowly.

Ultimately, the solution to these variables will depend on engine modifications, style of driving, and rpm. In general, the short-stroke pumps are well-suited to engines having siamesed inlet ports or one carb feeding multiple cylinders. This could then explain the Haynes recommendation of using the 40 DCOE-2 series with its 14mm long stroke. However it seems that to compensate for the long discharge duration, Haynes recommend that the bleed be closed.

Blanking off the pump discharge bleed ensures a rapid response, but this also means that the total gas quantity pumped by the piston differs little whether the accelerator pedal is moved slowly or rapidly, meaning that the mixture will be overly rich on gentle acceleration. Thus, among other things, a closed bleed will greatly increase gas consumption. IMHO, the dedicated owner could well improve any flat spots by experimenting with open discharge bleeds.

This may well be Weber's thinking when they suggest the 10mm stroke pumps with 50 bleed. Haynes were probably thinking of the Federalized TR6 motor with its 104hp. I suspect that Weber's recommendation is for Euro-spec motors, likely the original 150hp PI, or modified TR250/6.

Progression Ciruit

It seems that many Weber owners blame mid-range fade on the progression circuit. The different DCOE series do place the progression holes in in different places, but I have not confirmed if they differ between the DCOE-2 and DCOE-18 series. I need to do more research on the subject, but I can definitely state that the sizes of venturis, nozzles and emulsion tubes are not relevant to progression.

Air Horns (or Trumpets or Velocity Stacks)

This is an area often ignored by owners. Weber advises that the distance from the mouth of the carburator to the nearest obstruction must be at least equal to the bore diameter of the carburetor intake. This means the bore of the air horn , not the diameter of the entry flare. Many triple-Weber kits are supplied with 35mm high horns which may look impressive, but most TR6 owners remove them because they are too long for the 1.75" air cleaners that must be used in order to clear the inner fender arch. This is a BIG mistake. Never run your DCOEs without air horns that insert into the bore. Do not use air horns that simply bolt-on and are readily available and cheaper. An important function of the air horn is to hold the auxiliary venturi in place. Without the air horn, the aux. venturi will not fall out, but it will rattle around in the breeze. Low profile (12 or 13mm) air horns are available which will allow you to use air cleaners. This is probably one reason why TR6 owners become frustrated with their DCOEs.

However, there is a down side to running short air horns, relating to smoothness of torque delivery and the amplitude of the pressure-wave or "standoff" which appears as a spray of fuel mist during over-run. Remember, the one choke per cylinder of the DCOE acts like an organ pipe, so the length of the tube from the center of the intake valve to the entry flare of the air horn. Passini suggests that this length be about 4 times as long as the piston stroke. I've not made the mesurements, but I'm sure that S&H, Cannon and TWM who cast the intake manifolds were aware of this and chose the 35mm air horns as providing the optimum length for the TR6. I'll confirm this in due course.

So, if you have the space, use the 35mm high horns with 3.5" K&Ns. If not, run with the 12mm horns and the 1.75" K&Ns.

Air filter socks: If you are running horns and wish to run an air sock, ITG make socks for TR6s running DCOEs on TWM manifolds. Use a ITG JC100 series filter with a 36-JC-100 backplate (presumably for 36 DCOE). This snippet from TerriAnne Wakeman gleaned from an old TWM catalog.

Fuel pressure

Webers are very sensitive to variations in fuel pressure and quality. Install the biggest and best fuel filter you can buy (the FRAM HP-1 is recommended). If your Webers seem to lose their edge with time, it is probably because of dirt in the jets. Remove each jet and blow it clean. Only 10 minutes work, but you will be rewarded with pristine performance again.

The standard Triumph fuel pump is totally inadequate. Webers need lots of fuel flow but can't stand pressures over about 5psi (3-4psi is a good number). The shiny-toy pressure regulators sold in discount stores cannot flow enough fuel to keep three big float bowls full at high engine speed, unless you use one per carb. An unregulated stock fuel pump will put out up to 8psi at hi-rpm which will sink the floats, causing other problems.

Cams

Discussions with people who have successfully implemented multi-Weber installations, it seems that the key issue to resolving the Weber's lack of popularity amongst amateur tuners is the cam. Matching the cam to the Webers appears to be of prime importance, because then nominal jetting can be used.

Also see my article on performance cams.

What constitutes a good cam? It appears that Webers prefer cams with long duration. This makes sense because there is little vacume provided in the DCOE/IDA design, and the long duration is needed as a compromise.

References (in no particular order)

"Weber DCOE Series Manual", Weber Part # 95.0022.35
"Weber Carburator Manual", Haynes Techbook, 1995
"Performance Manual", TriumphTune/Moss Europe Ltd, 1992
John Passini, "Weber Carburettors, Theory, Tuning and Maintenance", MRP Speedsport, 1992
Pat Braden, "Weber Carburetors", HP Books, 1988
TerriAnn Wakeman, DCOEs for TR2/3
Paul Tegler, DCOEs for Spitfires
John P. Fitzgerald, "Triumph TR6 Performance: Parts, Sources & Procedures for the Enthusiast", 1996
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Varastorm
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by Varastorm »

Not much action been going on down the shed tbh, I've been forced into building a kitchen instead .

Evening wise though, I've been looking into the possibility of running a high level exhaust.

My main reason is that if I use the Vtr peg hangars, the point were the silencer starts to angle up after the peg is too long & I think it'll look wrong.

The original picture gets away with it because the footpeg is under the clutch casing. If I did the same, turning right would cause the peg to touch down too easily.

It's going to be fiddly, expensive & time consuming to sort out, but I am going to give it a go.

So I've sent Santa my parts list.

First order is 12 (should be enough) 45mm mandrel bends from the same guys in China that the 50mm inlet bends came from. Hopefully they'll be under the tree soon.

The exhaust I've chosen to copy is the new Harley xr750 Vance & Hines setup.

Whilst hunting for ideas last night I found this picture of the uncovered exhaust I want to make.

Image

I had a feeling it wasn't nice & simple under the heat shield as I've found no other pictures of the system.

Looks as if I might need more bends..
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sirch345
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by sirch345 »

Varastorm wrote: Wed Nov 22, 2017 11:27 am Not much action been going on down the shed tbh, I've been forced into building a kitchen instead .

Evening wise though, I've been looking into the possibility of running a high level exhaust.

My main reason is that if I use the Vtr peg hangars, the point were the silencer starts to angle up after the peg is too long & I think it'll look wrong.

The original picture gets away with it because the footpeg is under the clutch casing. If I did the same, turning right would cause the peg to touch down too easily.

It's going to be fiddly, expensive & time consuming to sort out, but I am going to give it a go.

So I've sent Santa my parts list.

First order is 12 (should be enough) 45mm mandrel bends from the same guys in China that the 50mm inlet bends came from. Hopefully they'll be under the tree soon.

The exhaust I've chosen to copy is the new Harley xr750 Vance & Hines setup.

Whilst hunting for ideas last night I found this picture of the uncovered exhaust I want to make.

Image

I had a feeling it wasn't nice & simple under the heat shield as I've found no other pictures of the system.

Looks as if I might need more bends..
That exhaust looks the part, plus both headers appear to be the same length,

Chris.
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Varastorm
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by Varastorm »

I've looked into exhaust making before Chris & it's quite complex to say the least.

Lots to learn, but my thinking is if they've (Vance & Hines) made it I shouldn't go too wrong copying them.

There'll be no increasing of the diameter though, that's a little too hard for me to do. Just plain old 45mm all the way :thumbup:

Checked the letter box earlier to avoid any soaked letters as it's pouring with rain & blowing a gale here.

Woo hoo! Santa's been early

Image

It's been just over a week since ordering from China, I'm thinking that they must have a depot in UK.

Next on the list is a meter length of 45mm tube & a bag of Mikalor clamps.

That should give me an idea of the length of silencers to buy, especially after attempting to make the 2-1-2 link.
Last edited by Varastorm on Wed Nov 22, 2017 5:12 pm, edited 1 time in total.
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AMCQ46
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by AMCQ46 »

that's perfect set up and looks the biz
AMcQ
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Varastorm
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by Varastorm »

AMCQ46 wrote: Wed Nov 22, 2017 5:05 pm that's perfect set up and looks the biz
They really do look great AMCQ46, the total outlay is going to be around £200 ish :eek2

£55 for the bends.
£25 for the length of tube.
£20 ish for a bag of Mikalor clamps
£40-£50 each for the silencers depending on length.
Find some stainless 6mm plate & 52mm tube for mounting to the heads.

Just hope it works out :lol:

The wife keeps asking me how many exhausts I need & which bike it's for.

I just say its for Christmas & start talking about which perfume she wants for Christmas :beer:

I won't mention that all I can muster is a nicked tester of "Suddenly Woman 1" from Lidl :lol:
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Varastorm
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by Varastorm »

Finished the kitchen I was press ganged into building :beer:

Back to things that really matter :lol:

I'm full of cold so I feel my best medicine is sitting in front of a pc with 4 layers of clothes on looking for parts for the build.

I'm still running with the new Harley exhaust idea & appreciate it might not work & may be a total waste of everything. Here's my thoughts though & what's been purchased so far.

As mentioned previously, I've gone with 45mm stainless headers.

I've already purchased a box of 12x 90° bends.

Me being lazy I've ordered 4x 45° bends, just in case..

Some "Weld on Ferrule Sanitary Pipe Fitting" which will (Hopefully) be header flange's, 2 pairs ordered = 4 flanges.

I've also bought a box of 10x Mikalor W2's 43mm-47mm clamps to hold it all together prior to welding.

My biggest gamble has been the silencers, if you can call them that.

Whilst studying the Vance & Hines setup, nice flowing headers piped to a nasty complex "X" then 2 fat stubby silencers.

I was originally going to go with some silencers that I mentioned in previous posts. They looked okay, but a bit basic tbh, so I looked for prettier items & I think I've found some.

Don't laugh too loud but with space being very limited I'm going to have a pop with these.

I forgot to mention that they're stainless & cost £17.99 delivered.

A pair have just been ordered for £35.98 delivered.


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VTRDark
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by VTRDark »

This bike is going to be awesome. I feel this is a critical point when it comes to your exhaust and I understand your pretty much banging it together right now and seeing what fits and looks right but here's a couple of links that may be worth having in mind when to comes to cutting and routing your pipe up and getting the length.

How To Calculate Muffler Size and Exhaust Pipe Diameter

Exhaust System Theory 101

Lemsip and a bit of R&D is all posotive work towards the end result and better still the wife wont disturb you now she's locked away in the kitchen :thumbup:
==============================Enter the Darkside
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Varastorm
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by Varastorm »

Thanks for the advice & links VTRDark, just read them both & the majority of the comments, cracking read :thumbup:

Calling it complicated just doesn't do it justice & it makes me feel way out of my depth tbh.

I would like to add (not to you VTRDark) but to the readers of this build, that the only purpose of me building my own exhaust is for looks & not for any performance gains. Like what's been said in the links that VTRDark has added, I'm not trying to re invent the wheel. I'm just trying to make a great looking exhaust.

I'll also add that I am really looking forward to running her on a dyno if it ever gets finished.

Here's the reasons I've done what I've done.

When I made the intake manifold, I was surprised how easy it came together. The Mikalor clamp idea has given me the confidence to take on the exhaust build, a project within a project.

My only reasons for choosing a 45mm pipe were that I could utilise the oem header flanges. The plan was & might still be to cut the oem ends off & slide into the 45mm stainless bends. I've now bought some other stainless flanges, so I'll see what's what when they arrive. I would like to fabricate it all in stainless if I can.

I'll also add that the V&H Harley exhaust that I'm attempting to copy will guarantee a power hike for Harley, but I've really been put off by the required X joint for scavenging. I think I can safely say V&H aren't too proud either or they'd have it on show, instead of hidden behind the heat shield that portrays the two pipes running in parallel.

I've spotted these @ £23.99 + £2.99 p&p, a bit expensive but look quite similar to the V&H setup.

Two welded together would work & look similar, but just not keen tbh.

Image
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fabiostar
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by fabiostar »

what a great read this has been... now get away back out and get some work done lol :clap:
the older i get,the faster i was :lol:
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Varastorm
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by Varastorm »

fabiostar wrote: Wed Nov 29, 2017 7:20 pm what a great read this has been... now get away back out and get some work done lol :clap:
Too cold Fab, way too cold for me anyway. Getting too old to be fiddling in the cold.. Sure there's a song in there somewhere :lol:

Ordered a new goodie for under the tree :D a 1250mm length of stainless :thumbup:

Christmas is gona be brill this year :beer:

Also been looking into these Chinese exhausts I've bought that no one can see anymore :thumbdown:

Image

They look a bit like a SC PROJECT exhaust knock off :eek2

Image

If they sound anything like this I'll be over the moon.
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sirch345
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Re: Project Varatrackerstorm or Firetrackerdero.

Post by sirch345 »

Varastorm wrote: Thu Nov 30, 2017 4:15 pm
fabiostar wrote: Wed Nov 29, 2017 7:20 pm what a great read this has been... now get away back out and get some work done lol :clap:
Too cold Fab, way too cold for me anyway. Getting too old to be fiddling in the cold.. Sure there's a song in there somewhere :lol:

Ordered a new goodie for under the tree :D a 1250mm length of stainless :thumbup:

Christmas is gona be brill this year :beer:

Also been looking into these Chinese exhausts I've bought that no one can see anymore :thumbdown:

Image

They look a bit like a SC PROJECT exhaust knock off :eek2

Image

If they sound anything like this I'll be over the moon.
You never fail to amaze me what you find on the net :clap:

Keep up the good work 8)

Chris.
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