5 replies to this topic

[hatchet]

Hello there!

Got a slight problem on my current Mini Cooper. Whilst accelerating the engine seems to fade and then pick up again with a bit more pedal pushing. I'm running a 1275cc with twin carb and stage one kit (1.75" bore exhaust). I've adjusted timing, air and fuel mix to no avail. The problem is alieviated with choke about half out, but this then creates idling problems once the engine has warmed up. Could this be a needle profile problem? Any ideas would be much appreciated , cheers!

[Bluemini]

Could be the needles/mixture, the dashpot springs, balance or worn or sticking componants... Twin carbs can be a *Female doggy* to set up and maintain!!

Best thing to do is take the dashpots off and strip them and clean them. Cheack for any wear too and that they are moving freely.

[Metmachex]

Ok good advice posted before,had a similar prob some years ago with twins Iceing up.Now it does,nt have to be freezing cold its down to air temp etc and the fact that unleaded fuel aint so good.Quick cure is nip to a local motorbike shop and see if the stock a product called Pro FST made by Silkolene/Fuchs,add some to the tank and see if it cures the prob.The product is a fuel conditioner and will do no harm to your mini.Should you decide later to go for a single carb setup use the Hif44,twins look good but if you are useing a twin 1&1/4 setup then you will not be gaining any power over a single setup.The standard mini manifold for twins also flows badly and robs you of power.Hope you get sorted!!

Metmachex

[hatchet]

Cheers

Had the dashpots off recently to see what needles were in there (aac's I think). Gave them a good clean up and no significant signs of wear.
I will probably buy some new needles to try, might as well get some new springs while I'm at it. Any thought's on which needle profile to go for (I was thinking an AAM). What are your thoughts on damper oil? Any ideas on where I could get a reasonably priced balancing meter?

[David_J]

I've got twin SU's on my spitfire, they're a bit easier to access and set up on the spit as the whole bonnet hinges forward with the wheel arches - but anyway.

I had a similar problem when I fitted better air filters and a tubular exhaust manifold. The key indicsator is that when you pull the choke out and richen the mixture the 'flat spot' dissappears implying incorrect needle profile.
Putting in richer needles solved the problem for me but I wouldn't know what to recommend for the mini.

If you know that the rest of the set up is correct then I would suggest looking at swopping needles but if you are a bit doubtful of the entire carb set up then going back to basics and setting all the linkage adjustments from scratch is worthwhile. Once they are done they generally don't need adjusting again.

Goood luck

:grin:

[Bluemini]

If your gonna get new needles, you'll probly be best off taking your mini to your local rolling road tuner. They will have a better idea of which needles to fit because there are hundreds to choose from...

If your after a balance meter, dunno were to get one from - try ebay?