17 replies to this topic

[96minimig]

Hi there a family member of mine has bought a mini with a 998cc engine with a 1 1/2 SU HS4, LCB and maniflow inlet. and it has a 1.75" back box think its a maniflow. it was stood for two years only run a few times. we have got it serviced and ready for its MOT soon. service wise i changed the oil/filter, spark plugs and leads, and also fitted a electronic ignition kit with a new coil. I had help from a friend to set up the timing and the mixture to the best we can using the colour tune plug. It now idles like a dream and is ok at half or gentle throttle when driving but if you stamp on it or give it more load/ full throttle it has a slight stutter. sorry if this sounds vague but can't determine whether its ignition misfire or mixture stutter. its the best we can get it with a timing strobe and colour tune plug. the carb was cleaned and has had a thorough going over and it seems ok.

 

The only thing i can think of it could be is the needle. don't know if its worth taking it to my local rolling road to have work or changing the needle will help.

 

any ideas or suggestions would help alot cheers.

 

Chris

Edited by 96minimig, 19 May 2013 - 09:10 PM.

[petey81]

have you checked dash pot oil?

[96minimig]

hello,

Yes dashpot oil is right up to the ridge as you look in the hole. forgot to say i topped it up with 3 in 1 oil.

 

The valve clearances haven't been done yet they are on the list. Can't imagine they would give the kind of stuttering i am getting from the valve clearances. It does have one tappet slightly loose listening to it on idle.

 

Thanks for the feedback. Can't put my finger on it. I have always worked on Spi cars but have a little knowledge on carbs. So its a learning curve.

 

I did spot a pin hole fuel leak on the fuel pump to carb rubber hose thinking that might be why its stuttering sucking air in the hole but put a new hose on, fuel clipped up tight and its still stuttering. Its like a hesistation stutter as if the revs won't pick up only slightly when it does it.

Edited by 96minimig, 20 May 2013 - 06:29 AM.

[petey81]

correct coil? you said stood for 2 years did you empty out tank and put fresh petrol in? also check carb bowl isn't sticking on the float needle valve and no kinks.

[Mighty made]

Vacuum advance, no leaks and not sticking when the advance is needed?

[coopdog]

Get it on a rr

[Ocado Man]

I agree completely with coopdog. Even though you may have set the timing as stated in Haynes, they are generic figures. If you take it to a RR then they will optimise the mixture & set the timing dead on. Once you know the timing for your engine you can phaff around with it to your hearts content.

 

Haynes says my 1275 should be 5 + 1 BTDC. The optimum for Lulu, as discovered after a session on a RR, is 16 BTDC.

[96minimig]

cheers for the replies peeps. There are no air leaks or kinks as it did have a massively blowing manifold gasket on the exhaust radiator side but i replaced the gasket. We cleaned all the float and check the valve works which it does without sticking. Before starting we put fresh petrol in as there was barely any to start it anyway lol. two lawn mower cans so 10 litres approx.   It has the electronic coil for the electronic ignition. imo i not a fan of points and the condensor on the points had failed anyway as we couldn't get a spark.

 

Can't think of anything that will make it run better apart from a proper more in depth tune on the rollers. will let my faimly member know this. it idles spot on...

 

The other thing is the owner before has fitted a maniflow inlet with the spacer on so the standard air box is a right pain in the backside to get on and off and the previous owner has cut half the air box away at the back. I might advise my friend who owns it now to fit a K&N cone filter so its a little easy access. however will this chuck the fuelling out even more BEFORE the rolling road or will it be ok enough to get to the rollers and then set it up. As don't want to do it backwards and fit the cone filter after the rolling road....

 

??

[96minimig]

anyone got any thoughts on my last post.... cheers

[robminibcy]

you say you filled the dashpot up to the ridge, is that the top of the actual carb(so if you screw the damper in it will squirt out). If so empty it out and try again with less. If not it won'tt hurt to try differant or less oil anyway just to see if it makes a differance.

[KernowCooper]

What needles in it now?

[96minimig]

no top of the ridge on the dashpot stick. theres not to much in there. this had no affect on the running anyway even after i topped it up.

 

Sorry I have no clue what needle is in there. Which makes me think it can only be that and prob a slight bit of timing adjustment needed

Edited by 96minimig, 21 May 2013 - 06:40 AM.

[petey81]

check needle it seated correctly as screw  holding it in may of come loose.

[mrbridger]

Have you still got the original coil? If so, try putting it back on for a test. I switched to electronic ignition and fitted a Lucas gold sports coil. My mini didn't like it at all, spluttering etc. put the original one back on and sorted the problem. may be your electronic coil is faulty or unsuitable.

[96minimig]

tried the coil still is the same. sorry i sound a pain lol.. Haven't checked the needle screw guessing you take the dashpot screws out and lift the dashpot out?