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how to tune twin 1/2.5 SU's

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(SuX-855)

Post subject: how to tune twin 1/2.5 SU's

Posted: Wed Jan 19, 2011 10:47 am

848cc

Joined: Sun Jan 25, 2009 10:15 pm
Posts: 218
Location: Adelaide - Gawler

how do u tune then one side is running really lean and the other basickly nothing

_________________
1974 clubby with round nose conversion
1100 motor
extractors
twin 1 1/4" su's
lumpy cam (dunno what 1)
2 1/2" exaust
http://www.ausmini.com/forums/viewtopic ... sc&start=0

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Wombat

Post subject:

Posted: Wed Jan 19, 2011 10:53 am

1360cc

Joined: Mon Jul 26, 2004 7:23 am
Posts: 7339
Location: Sunny Shine Coast, Qld Australia

http://www.sterlingbritishmotoringsocie ... _Carbs.pdf

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David L

My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

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(SuX-855)

Post subject:

Posted: Wed Jan 19, 2011 11:12 am

848cc

Joined: Sun Jan 25, 2009 10:15 pm
Posts: 218
Location: Adelaide - Gawler

i still got no clue its running rich i know that much

_________________
1974 clubby with round nose conversion
1100 motor
extractors
twin 1 1/4" su's
lumpy cam (dunno what 1)
2 1/2" exaust
http://www.ausmini.com/forums/viewtopic ... sc&start=0

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Hanra

Post subject:

Posted: Wed Jan 19, 2011 11:16 am

1360cc

Joined: Sat May 08, 2004 9:01 pm
Posts: 6844
Location: Cairns, Nrth QLD

Pretty open ended question.....

Whats the condition of both carbs? Throttle bushes etc.

What needles are they running?

What springs are they running?

What dashpot oil are they running?

Have they been kitted recently?

Are both float levels correct?

Are they balanced correctly?

What engine capacity and mods?

Invest in one of these:

http://www.gunson.co.uk/item.aspx?cat=675&item=1813

and one of these:

http://www.gunson.co.uk/item.aspx?cat=0&item=1822

_________________

http://www.youtube.com/user/Hanras

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Wombat

Post subject:

Posted: Wed Jan 19, 2011 11:21 am

1360cc

Joined: Mon Jul 26, 2004 7:23 am
Posts: 7339
Location: Sunny Shine Coast, Qld Australia

Check the basics first - same needles both sides - float bowel set up the same - start with same number of turns on the jet- then follow the above manual step by step

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David L

My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

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BBY755

Post subject:

Posted: Wed Jan 19, 2011 11:26 am

1098cc

Joined: Wed Aug 06, 2008 10:14 am
Posts: 1370
Location: Sydney

yep - Gunson to the rescue - Carbalancer and Colourtune - easy peasy!!!

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Cooper S Mk2
Cooper S Mk1
ex Cooper S Mk2, various Morris 1100s, 1300s, 1500s, Leyland Sherpa!

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(SuX-855)

Post subject:

Posted: Wed Jan 19, 2011 11:29 am

848cc

Joined: Sun Jan 25, 2009 10:15 pm
Posts: 218
Location: Adelaide - Gawler

how do u find out what needle it is im a noob and dont wanna stuff it up

_________________
1974 clubby with round nose conversion
1100 motor
extractors
twin 1 1/4" su's
lumpy cam (dunno what 1)
2 1/2" exaust
http://www.ausmini.com/forums/viewtopic ... sc&start=0

Top

Hanra

Post subject:

Posted: Wed Jan 19, 2011 11:32 am

1360cc

Joined: Sat May 08, 2004 9:01 pm
Posts: 6844
Location: Cairns, Nrth QLD

If thats the case, perhaps you should ask for some guidance from an experienced SU tuner in your area?

_________________

http://www.youtube.com/user/Hanras

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Post subject:

Posted: Wed Jan 19, 2011 11:35 am

1098cc

Joined: Wed Oct 01, 2008 11:14 am
Posts: 1906
Location: Brisbane Qld, North side

mate my advice after having twin su's & still having them they are great but a pain in the ass.

i would go a hiff44 single

get hold of the gunson thing & tune best would be go to a dyno & get it set up right

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Hanra

Post subject:

Posted: Wed Jan 19, 2011 11:38 am

1360cc

Joined: Sat May 08, 2004 9:01 pm
Posts: 6844
Location: Cairns, Nrth QLD

Wombat wrote:

http://www.sterlingbritishmotoringsociety.org/files/Tuning_SU_Carbs.pdf

If you take the time to read through this it will explain/show how to remove the needle from the piston assy. You will need to do this and look around the top shank of the needle it will have engraved in it a combination of letters/numbers, numbers only or letters only. Compare both needles and ensure they are the same.

What vehicle did these carbs come off?

_________________

http://www.youtube.com/user/Hanras

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(SuX-855)

Post subject:

Posted: Wed Jan 19, 2011 11:47 am

848cc

Joined: Sun Jan 25, 2009 10:15 pm
Posts: 218
Location: Adelaide - Gawler

not to sure they were on the car when i bought it

_________________
1974 clubby with round nose conversion
1100 motor
extractors
twin 1 1/4" su's
lumpy cam (dunno what 1)
2 1/2" exaust
http://www.ausmini.com/forums/viewtopic ... sc&start=0

Top

Hanra

Post subject:

Posted: Wed Jan 19, 2011 12:24 pm

1360cc

Joined: Sat May 08, 2004 9:01 pm
Posts: 6844
Location: Cairns, Nrth QLD

Wombat wrote:

http://www.sterlingbritishmotoringsociety.org/files/Tuning_SU_Carbs.pdf

Well this will help you a lot.

_________________

http://www.youtube.com/user/Hanras

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