Carb Needle Options

How do you improve the performance of your beastie?
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Carboy0
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Carb Needle Options

#1 Post by Carboy0 » Tue Dec 18, 2018 9:33 pm

Hi all, I am hoping that someone has been down this road before me. My new purchase has its original 2 litre engine, but a previous owner has fitted twin HS6 SUs from a 2500 S, with the matching separate air filter unit, elephant trunk and air collector box.

The car runs well, but runs rich throughout the rev range, I’m guessing and will check, but I expect that the original 2500 S needles are still fitted.

Does anyone have any experience of switching needles and how it has worked? I don’t want to fit too lean needles for fear of damaging the engine.

All contributions gratefully received.
Chris

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Phil T
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Re: Carb Needle Options

#2 Post by Phil T » Wed Dec 19, 2018 8:56 am

Try speaking to Burlen who deal with all the SU carbs stuff.

They will recommend a needle and jet.

http://sucarb.co.uk/technical/

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Re: Carb Needle Options

#3 Post by johnnydog » Wed Dec 19, 2018 9:21 am

I think Chris Witor may have some knowledge on the best needles for your carbs / engine. Worth a phone call at least.
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1967 Mk1 2000 in Gunmetal Grey
1969 Mk1 2000 in Royal Blue
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Alec
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Re: Carb Needle Options

#4 Post by Alec » Wed Dec 19, 2018 3:08 pm

Hello Carboy0,

why not try weakening the mixture a bit first? If it's rich thoughout the range it doesn't sound as though the needles are far off?

Alec
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Carboy0
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Re: Carb Needle Options

#5 Post by Carboy0 » Wed Dec 19, 2018 8:51 pm

Well, a torch (literally) has shed some light on what’s going on with the carbs.

The front one is tagged FZX 1263F and the rear one AUD 678R!

According to Burlen Fuels website neither tag number have ever been used, although they are within a couple of digits of some genuine 2000 Mk2 TC carbs!

I checked the numbers three times to be sure, so I now have an enquiry out with Burlen Fuels, I’ll keep you all posted.
Chris

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tony
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Re: Carb Needle Options

#6 Post by tony » Thu Dec 20, 2018 3:05 am

I would have thought that an HS6 is an HS6 irrespective of the numbers. Take the needles out and check the numbers on them. If you have eyes like mine you may need a magnifying glass. If they are the same have a look at 'Minty Lamb ' on the web . When I had fuelling problems on my S a couple of years ago,I finally replaced the jets which were worn and hard to see by eye. Fixed my problems. :shock:
Tony.
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Carboy0
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Re: Carb Needle Options

#7 Post by Carboy0 » Thu Dec 20, 2018 1:32 pm

Thanks guys

Burlen has confirmed that the carbs are for the Triumph 2500 TC, one has a standard jet and the other a waxstat jet.

Well at least I know what I have got. The plan is to rebuild them to 2000 TC spec with standard jets and standard 2000 TC needles.
Chris

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Saffron 2000 TC Man O/D - actually 2500 TC Man O/D - bit of a project.
Magenta Stag 3.0 Man O/D

Mike Stevens
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Re: Carb Needle Options

#8 Post by Mike Stevens » Sun Dec 23, 2018 12:36 pm

Later 2000s used the HS6 carbs on the long manifold, so the needles (and maybe springs too) specified for one of those would be a good start.

I have the Burlen books here so I can check the needles for a 2000 if you wish.

I would strongly suggest you ditch the waxstat jet! There are (were?) conversion kits available for that.

Cheers,
Mike.
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Carboy0
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Re: Carb Needle Options

#9 Post by Carboy0 » Sun Dec 23, 2018 3:41 pm

Hi Mike,

I am in touch with Burlen Fuels and with their have identified a good spec for a 2.0 litre engine on HS6s. The rear carb with waxstat will be rebuilt with the simpler jet, using the Burlen conversion kit.
Chris

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Saffron 2000 TC Man O/D - actually 2500 TC Man O/D - bit of a project.
Magenta Stag 3.0 Man O/D

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Re: Carb Needle Options

#10 Post by Mike Stevens » Fri Dec 28, 2018 9:15 pm

Great, good luck with that! I put a pair of HS6s on an early 2000 many years ago, but despite me searching all the paperwork, I never did find which needles I used!

Cheers,
Mike.
(South Oxfordshire)
Register Member No 0355
1971 2.5PI Saloon Sapphire blue
1973 2.5PI Saloon rust some Honeysuckle
1973 Stag French blue
(1949 LandRover was blue should be light green!)

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