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



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).

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i like to drive on rails

I'd take it somewhere with a dyno, that does SUs.

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.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

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?

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i like to drive on rails

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.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

matt, take it out to roy goodman! he is a whizz with the needles

they were rebuilt about 4 yrs ago.

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i like to drive on rails

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

fix your clutch return spring bracket - the one on the end of the clutch arm....

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

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.

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

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

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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!

sounds like its running ****** rich, try some different needles

Good to see you mate, one day hey one day

Jon

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Roundies and Clubbies(except vans) are both ugly that is why I have Midas and a van
1293 Mini Midas Bronze,1275 Clubman van

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.

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i like to drive on rails

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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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.