27 replies to this topic

[IainNeon91]

i'm pretty sure it's leaning out because of the new cone filter, no enough fuel to match the air...

What needle is in the carb?

The standard one for the hif 38 i think AEM or somethign like that

And you are wondering why it is lean with a cone type filter....

I assumed the person who sold me the carb had a cone filter too haha

[IainNeon91]

Can anyone confirm that this may be the issue?

Many thanks!

[KernowCooper]

The Slide assembly should be able to drop down under its own when assembled and the spring is fitted in the dash pot, (you do have a spring) The needles not bent is it? does the slide drop with the needle removed ?
screw the idle screw down until you get it to idle, and now lift the lifting pin to lift the slide, if the engine splutters and cuts out the engine is to weak so wind in the mixture adjusting screw a small amount to richen it and keep lifting the pin after adjusting the mixture screw until the revs just rise a small amount and settle again, thats the idle mixture set as close as you can get it without a CO meter.

The needle you say is a Hif 38 is a AEM or something like that, the Hif 38 was fitted to the later 998s and also the non Cooper 1275s so you need to take the needle out and find out whats in yours. Then its back to experience a fair bit as your fitting a cone filter whick will make the engine run a touch weak, so its 2 options, 1. you have a rolling road session to get the right needle or a custom profile made 2. You read here what others here are using with a similar engine spec as yours and try that needle, but it could be acceptible or it could not suit your engine as there exhaust/inlet/cam/ is different to yours.

Take your needle out and read whats in there now and put the spec here of your engine Size/Mods

Edited by KernowCooper, 27 February 2013 - 09:29 PM.

[IainNeon91]

I will check all of the above tomorrow and will report back.

I do have a rolling road session booked on the 22nd March. But i will have to get it to run without cutting out to get there obviously haha.

I'm pretty sure it is an AEM, if it is, i have a AAU needle which was in my HS4. These two carbs being the same size, would it be worth try the AAU inside the HIF38?

Also i don't have a lifting pin on the side of my carb.

Many Thanks,

Iain.

[KernowCooper]

Hif 38/44 types are spring loaded needle and you cant fit the earlier type of fixed needle in it

[IainNeon91]

It is a spring loaded needle in the HIF and the AAU is spring loaded as well. Would the piston fall down at all/unevenly (i.e. after each time of lifting the piston up, it stops at a different point?)

Cheers,

Iain.

[KernowCooper]

The Hif 38 is a spring needle carb so any needle needs to be the spring loaded type, only 3 things can stop the slide assembley from falling the needle, the slide and the internal damper.

Take the needle out and if the slide fall correctly look at the needle and the jet assembly, if it does not fall with the needle out correctly look at the slide and the dashpot cover, is there and damage marks in the dashpot which make it jam internally, then check is the damper rod is it damaged. Here will be the answer to the jamming on one of those components.

You did say in the dash pot there is a coiled spring?

Edited by KernowCooper, 27 February 2013 - 10:54 PM.

[IainNeon91]

Thank you very much!

[jaydee]

remove the dashpot and the piston, check the piston moves freely into the dashpot
If the dashpot is damaged (fallen somwhere etc) the piston will stick to a point
Same applies to the piston, those carbs are delicate

And yes use the AAU in the HIF38

[psychobob]

have you fitted the return spring back in the carb. i stripped mine to clean it recently and forgot to refit the spring when i reassembled it and it ran like a bag of spanners. d'oh!

[IainNeon91]

It's all fixed, thank you everyone!

I just took out the dash pot and piston, cleaned it up and set the mixture via lifting the piston with a screw driver, now runs beautifully!

I think i will put my AAU or an AAA in, because there is a flat spot if i give it the beans in 1st and second, around 4000 revs, which was expected from the AEM that's inside.

It's thicker needle than the AAU and AAA at the top end of the needle

Cheers,

Iain.

[Skortchio]

Foot to hear dude, but 4k isn't the top of the needle ;)

Check this site out:
http://www.mintylamb.co.uk/suneedle/

And have a google for god needle stations. Then you can find one using the link that has the alteration in the right point.

[IainNeon91]

That program is what i used to compare my needle to others