18 replies to this topic

[Dusky]

Hi all

 

Next week is mot time. Already fitted seats etc, mini is almost ready ( if someone has hints to test if the shockabsorbers / cones are still good, please tell me ;) )

 

But here is my problem : 

 

After tuning the carb, the mini now stutters on light throttle ( throttle 10-20% pressed in throttle) Any ideas why?

The problem became 'better' ( dind't stutter as much as before) when I connected the vacuum advance.. So is this a timing related problem? or hsould I look into mixture?

 

With full throttle the car has no problems ;)

 

Sorry for any bad spelling, but it has been a very long day for me.

 

Goodnight all! And have fun at IMM :)

 

 

Update:

 I'm using E3 needles with red springs now.
I thinkt hese needles are suitable  But I have some problems now, first problem is that he runs lean I think ( picture of a plug attached) so that will just be a case of enrichening the mixture and see how it goes.
Second : When I put my foot down the car doesn't react instantly, I have to wait a bit until he starts to go faster. Would this be caused by the lean mixture? Or should I try some lighter dashpit oil ( 20W50 oil in it now) , or maybe even blue springs?

Edited by Dusky, 04 September 2014 - 09:12 AM.

[KernowCooper]

After tuning the carb it stutters, To weak at idle and light throttle. Remind me what carb do you have ? and  weak mixtures like more advance to burn correctly.

Edited by KernowCooper, 30 July 2014 - 10:17 PM.

[Dusky]

Will try enrichening mixture.
My carbs are twin hs2's

[Dusky]

Tried richening it, doesn't really make a differance.

 

When I push the carb needles fully in the spluttering clears, but then my left carb runs too rich and the right one too lean. ( with mixture screws fully adjusted)

Should I swap the needles over?

[rally1380]

What needles do you have?

 

You got enough oil in the dashpot?

 

Checked for air leak?

 

For checking the shock absorbers...you can push down on the wing and check it doesn't just bounce around on the cone.....or the best way would be to take the shocker off and inspect it for leaks, if it still functions correctly and has some resistance. 

[Dusky]

What needles do you have?

 

You got enough oil in the dashpot?

 

Checked for air leak?

 

For checking the shock absorbers...you can push down on the wing and check it doesn't just bounce around on the cone.....or the best way would be to take the shocker off and inspect it for leaks, if it still functions correctly and has some resistance. 

Its defenatly mixture related I think.

Will check airleak

 

I have H2 needles in it.

 

998 cc Twin HS2 carb, 643 camshaft

[Dusky]

Could it be that the dashpot was way too full?

[rally1380]

what is your full engine spec?

[Dusky]

what is your full engine spec?

Stage 'Dusky' head ( standard valves)

Aeg 643 camshaft

998cc

Twin hs2's with AH2 needles

Electronic ignition

 

The point is that the car doesn't stutter when i push the needle fully in the piston.

But when I put the needle level with the piston surface ( as they should be fitted I am told) the car struggled + mixture settin was very difficult.

 

Now another question : howmuch should I lift the liftin gpins when setting my mixture?

[rally1380]

When I set the mixture on my carbs, I push the lifting pin all the way in.

 

I also sit the needles flush with the bottom of the piston (as you say - the correct way) - when pushed all the way in it ran ok on tickover but popped and banged when it went up the road - was terrible!!!

 

Once the needles sat flush ( using correct needles according to Dave Vizards book) it was much easier to set the mixture and ran no problem throughout the rev range.  Still needs to be rolling roaded, but runs fine with standard Vizard setup method.

 

Sounds to me that the needles you have may be wrong.

[rally1380]

Mr V's book says AH2 needles are 'standard 997 Cooper rich mixture' coupled with Red spring.

 

maybe try blue spring with either M or E3 needles?

[Dusky]

Seems like an M needle will fit better.

 

But any idea how I can pass MOT mot in Belgium ( got an appointment friday)?

 

Car must be drivable but can't be too rich at idle :/

[rally1380]

Seems like an M needle will fit better.

 

But any idea how I can pass MOT mot in Belgium ( got an appointment friday)?

 

Car must be drivable but can't be too rich at idle :/

 

Best bet to pass an MOT would be to swap out the twins for a single HS4 instead....much easier to setup.

 

Trouble is....IF you are running the wrong needles, then they may have the correct mixture at tickover but completely wrong further up the rev range...or vice versa and if the needle profile is wrong, then it is simply wrong.

 

Fingers crossed someone else will wade in to the discussion with a simple solution....??????

[Dusky]

 

Seems like an M needle will fit better.

 

But any idea how I can pass MOT mot in Belgium ( got an appointment friday)?

 

Car must be drivable but can't be too rich at idle :/

 

Best bet to pass an MOT would be to swap out the twins for a single HS4 instead....much easier to setup.

 

Trouble is....IF you are running the wrong needles, then they may have the correct mixture at tickover but completely wrong further up the rev range...or vice versa and if the needle profile is wrong, then it is simply wrong.

 

Fingers crossed someone else will wade in to the discussion with a simple solution....??????

 

A suite simple solution would be finding some needles in time

But can't find anyone who stocks M or GY needles.

 

Can't decide wich needle I need too, GY is for standard cooper, M is rich.

I have k&n cone filters, does that mean I need a rich needle? AH2 is way too rich anyways..

[Dusky]

Went through the mot without a problem.

Well only 1 problem actually : bad handrbke, but emissions are passed. Still deciding between M and GY needles :/