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SU Needle advise please
Posted: Mon Dec 27, 2010 10:43 am
by pad4
Hey guys - stranger here !!!!
Finally got my motor back and i need to put some milage on it but i need to throw a pair of needles in the carbs that are something like....as with the std needles in it will run but not idle, or idle but not run etc etc etc.......
engine spec...
twin 1 1/2 hs4
maniflow steel inlet
10.5:1 CR
37/29 valve size / mod head
1.5 keith dodd rockers
1310 cc
544 cam
What do you think needle wise ?? (its only so i can out a hundred miles or so on it befoere it goes to the rolling road for a bit more of a set up)
Cheers
Re: SU Needle advise please
Posted: Mon Dec 27, 2010 10:49 am
by austinisuseless
David Vizard's 'How to Modify your Mini' has a good basic list of SU carb needles and springs for various degrees of tuning, if I remember right. Will put in the right area. Maybe someone has a copy at hand - the copy I've got is in the attic somewhere, I will have to dig it out one day, if I can find it.
Or was it in his 'Modifying A-series engines' book? Will have to try and find that one too in the attic.
Re: SU Needle advise please
Posted: Mon Dec 27, 2010 11:27 am
by pad4
Yea ive got the books
he goes -
1275 / mod head / semi race cam ..........red spring No 3 or 4 needle
1275 / mod head / full race cam / extractor exhaust .....blue or red spring , BG needle
where calver says AAM or ABY
can any one improve on this ????
Re: SU Needle advise please
Posted: Mon Dec 27, 2010 9:58 pm
by austinisuseless
Sounds good to me pad. Needles in an SU carb are something else, aren't they, something to be lost in a discussion with the misses.
http://www.youtube.com/watch?v=60Bj_2cZQnc
Re: SU Needle advise please
Posted: Tue Dec 28, 2010 12:00 pm
by madaboutcherry
am i right in thinking that needles with a 3 digit code are sprung needle?
i have been recommended aau needles for my modded 998 cooper but i want to stay with fixed ones, i don,t trust all this modern stuff.
so are there equivalant fixed needles to match sprung ones?
Re: SU Needle advise please
Posted: Tue Dec 28, 2010 4:52 pm
by InimiaD
I'm fairly sure I used sprung needles in a set of twin HS 6.
I modified the needles by taking off the spring seat etc and Aralditing the needles in place.
They worked very well and never unstuck themselves.
Re: SU Needle advise please
Posted: Tue Dec 28, 2010 9:02 pm
by pad4
Delving further into this it seems like Vizard with BG needles are the one to go for, Calver is way off the mark as his needle selection would weaken out where power is peaking and needed most whereas the BG needles keep on fuelling...
so BG or there equivelent are the ones to go for ...