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twin su needles?
https://ausmini.com/forums/viewtopic.php?f=5&t=25713		 Page 1 of 2
Author:  mattsmini1971 [ Sun Dec 10, 2006 1:14 pm ]
Post subject:  twin su needles?
hi im having a bit of trouble with mixtures on my 1100. the motor has the following mods-
10.5/1 comp
police spec cam
1.5 roller rockers
ported & polished head with bigger valves
lightened and balanced bottom end.
electronic ignition
lcb extractors with 2 inch exhaust
Image


ive got m needles in at the moment with red springs and it is real rich at idle and cruising at 60 but at 100 or giving it a boot full its lean as hell whats the go?
should i just go a weber or dellorto (i think that how u spell it lol).
Author:  drmini in aust [ Sun Dec 10, 2006 6:46 pm ]
Post subject: 
I'd take it somewhere with a dyno, that does SUs. :wink:

With about 800? different needles now, you will be lucky to pick the right ones yourself.

However-
If rich at idle something is wrong, there is very little needle difference at idle. Maybe float levels are too high or main jets worn.

Ms are pretty common in twin HS2s on a motor like yours.
Author:  mattsmini1971 [ Sun Dec 10, 2006 8:59 pm ]
Post subject: 
another point i should say is when i sit at idle for about 30 seconds or more and then procide to drive away it always misses and coughs for a little while. what u think?
Author:  drmini in aust [ Sun Dec 10, 2006 10:09 pm ]
Post subject: 
I'd take the carbs off, strip them and fit a repair kit to each.
THEN get them tuned.
No point trying to tune them if float levels wrong, throttle shafts worn, main jets worn, etc. :wink:
Author:  Siclad [ Mon Dec 11, 2006 12:52 am ]
Post subject: 
matt, take it out to roy goodman! he is a whizz with the needles 8)
Author:  mattsmini1971 [ Mon Dec 11, 2006 5:43 am ]
Post subject: 
they were rebuilt about 4 yrs ago.
Author:  Rikki [ Mon Dec 11, 2006 5:49 pm ]
Post subject: 
Anywhere local in Brisbane to get the repair kits for the Twin's, i have the same carbs as in the pic and i seem to have a backfire, when idle and when driving, so its a bit hard to drive at the moment.

Cheers
Author:  simon k [ Tue Dec 12, 2006 8:10 pm ]
Post subject: 
fix your clutch return spring bracket - the one on the end of the clutch arm....
Author:  kiwiinwgtn [ Wed Jan 03, 2007 8:14 pm ]
Post subject: 
Check your electrical system before you blame the carbs, timing, leads, plugs, points, cap, rotor. I had a simular problem with a miss fire it turned out to be the dizzy and the cap. brought new needles etc.. took me ages to find

Most low rev miss fires are due electrical problems not fuel.

Hope this helps

Kiwiinwgtn
Author:  TheMiniMan [ Wed Jan 03, 2007 9:02 pm ]
Post subject: 
sounds like you have at least 2 problems

(1) -->"Maybe" your float levels are up to crap

& (2)--> "maybe" also your fuel delivery system isn`t up to scratch & not feeding enough "litres per minute",,, or there "maybe" could be a blockage in the line or similar ,,, "maybe" :-)

"Maybe" have all that stuff looked at.... "Maybe"

sorry, i don`t know diddly, just suggesting stuff "maybe"

Oh!!! & then "maybe" look at seeing "IF" the needles need changing once all that stuff is sorted.

:-)
Author:  Wombat [ Wed Jan 03, 2007 9:13 pm ]
Post subject: 
SU parts in Brisbane;

Progas
4/11 Didsmith St
Woolloongabba phone 3891 2424

I got my full kit from Mini Spares and and some parts that were needed from Progas - took a while for some bits and pricey
Author:  Spaceboy [ Wed Jan 03, 2007 9:33 pm ]
Post subject: 
sounds like its running ****** rich, try some different needles :D
Author:  feralsprint [ Wed Jan 03, 2007 9:36 pm ]
Post subject: 
TheMiniMan wrote:
sounds like you have at least 2 problems

(1) -->"Maybe" your float levels are up to crap

& (2)--> "maybe" also your fuel delivery system isn`t up to scratch & not feeding enough "litres per minute",,, or there "maybe" could be a blockage in the line or similar ,,, "maybe" :-)

"Maybe" have all that stuff looked at.... "Maybe"

sorry, i don`t know diddly, just suggesting stuff "maybe"

Oh!!! & then "maybe" look at seeing "IF" the needles need changing once all that stuff is sorted.

:-)


Good to see you mate, one day :lol: hey one day

Jon
Author:  mattsmini1971 [ Wed Jan 03, 2007 9:58 pm ]
Post subject:  sorted
got everything going pretty good now. for the first time i thought id give it a go myself. i took the su's of and replaced the jets and cleaned and tuned them up with a vacuum gauge i borrowed now its running like a charm, idles smooth and it doesnt cough and splutter after it idles for a while. one thing im still questioning is how much difference does the thickness of the oil make in the top of the su? thinner or thicker?

ive learnt now that if u want something done right do it urself.
Author:  drmini in aust [ Wed Jan 03, 2007 10:04 pm ]
Post subject: 
These days, most people find that ATF (auto tranny fluid) works well in the dashpot damper.
20W/50 is too heavy.
I found `3 in 1' sewing machine oil too heavy as well.
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