6 replies to this topic

[josh austin mini city e 82]

Morning all, fitted my new carb needle last night. It's the AAA type for my 1275 with stage 1 kit (the most recommended for the job) now iv not tinkered with the mixture yet as it was going dark when I got rebound to it. Ran it to work this morning and it's all over the shop. Full of flat spots and rough spots. The only time it was really ok was at full throttle 4500rpm +
Now my question is, is my fuel mixture going to be richer or leaner than it was ? Now off the top of my head I would say richer. I noticed the AAA needle was quite a bit thinner than the one I removed. Can't quite remember what needle came out -,- something like an AEM ?? So yes a thinner needle surely is going to mean I richer mixture ? Now question number 2, it's on a hif38 carb. Just to confirm the mixture screw is on the left hand side ? Toward the back of the carb? (As though you are looking at the engine from the front) and it's clockwise to richen anticlockwise to lean ?
Thanks
Josh

[KernowCooper]

You need to check the base CO% at idle Josh, and yes a thinner needle does mean a richer mixture, is your engine full stage one spec? yes thats the mixture screw and your right on the movement to richen/weaken.

 

The trouble is when you have a stage one kit developed by a company with one set of components and they recommend a needle its one they have tested and development done, there are a mass of components out there all being stage one kits but a small variation in component means that the needle most used for stage one kits by the developer of kit 1 wont be correct in kit 2.

 

List the full spec of your engine and the stage one kit used and what needle came out and we can advise

[josh austin mini city e 82]

Sorry for the late reply, I have a pipercross air filter, mini spares inlet, maniflow exhaust manifold, and an RC40 single box exhaust, oh and the AAA needle of cause. Everything else is standard to the 1275 sprite engine
How can I go about checking the CO% ?

[josh austin mini city e 82]

You need to check the base CO% at idle Josh, and yes a thinner needle does mean a richer mixture, is your engine full stage one spec? yes thats the mixture screw and your right on the movement to richen/weaken.
 
The trouble is when you have a stage one kit developed by a company with one set of components and they recommend a needle its one they have tested and development done, there are a mass of components out there all being stage one kits but a small variation in component means that the needle most used for stage one kits by the developer of kit 1 wont be correct in kit 2.
 
List the full spec of your engine and the stage one kit used and what needle came out and we can advise

Sorry for the late reply, I have a pipercross air filter, mini spares inlet, maniflow exhaust manifold, and an RC40 single box exhaust, oh and the AAA needle of cause. Everything else is standard to the 1275 sprite engine
How can I go about checking the CO% ?

[KernowCooper]

Base setting with CO meter and then rolling road to see if a standard needle profile needs adjustments at various points on the needle profile.

Edited by KernowCooper, 20 March 2014 - 05:19 PM.

[josh austin mini city e 82]

Base setting with CO meter and then rolling road to see if a standard needle profile needs adjustments at various points on the needle profile.

I was going to book it Into a rolling road but never got round to it. Iv been playing with it since I got in from work and it's about there. Running sweet now. It was running very rich ! Spark plugs were matte black. Weakened it quite a lot bit by bit doing a test drive after each half turn then when it was about there just adjusted it a little bit at a time and it's all good now !

[KernowCooper]

Just take some plug readings over the next few trips and see what its like