8 replies to this topic

[amr27]

I have a 998 engine, inch and 1/2 SU with a bad misfire and boggy feeling when accelerating heavily. And it tends to be very slow and dead. But once the choke is pulled out it changes into a totally different car and goes well. I've tried adjusting the mixture to give it more fuel but still no real improvement.
Could it be the needle?

[jaydee]

First check the usual like dashpot oil, air leaks, tappet clearance and ignition. 

What needle is in the carb and what modifications have been done to the mini?

[amr27]

Checked all those things and they seem fine. Timing is advanced 10 degrees now, it has a sportex exhaust, lcb manifold, highlift cam, stage 3 head and duplex timing chain. It has an AAC needle which is too lean I think? It won't even take revs at all now without out dieing out and spluttering. And the plugs are a creamy white colour

[jaydee]

Exactly, what cam, what valve size and what air filter are you using?

AAC is way too lean 

[amr27]

I'm not sure about what cam and valve size as the guy that had it before me got that all put on it, it's a k&N filter. What needle do you recommend?

I'm worried I've done damage to the car now not realising it had such a lean needle in it? I tried shifting the needel position about a few times earlier and taking it a spin, and it's just made it worse, it's undriveable now and just won't take revs at all

[jaydee]

You need it to be rolling roaded then.

Use an AAM needle to take the car to the rollers, set idle at 3.0% CO with gas tester or if using colourtune, you want a blue flame with intermittant yellow flames.

[amr27]

I'm in Northern Ireland and there's no1 with a rolling road that works with minis. And anyone who does work at minis that i know of are old school. So I have a problem there

[jaydee]

Do you have access to a gas tester?

[amr27]

I don't have one but will do some research and see if I know anyone who does.
Ps Thanks for the advice!