Cracking and banging of of exhaust

[advinnie]

I have a stock coil with a locked out 009 distributor with pointless ignition until inside of it all being controlled by the CB performance black box ignition system

[rs58rag]

Ok, should I go from the two 70’s to 75 or take a big jump up to 85? I only ask cause I can only find 75’s and 85’s but nothing in between

First, make sure air filter is not over oiled, this will bog engine down and cause rich readings.. .60 pump jets and 55 idles should be good. Make sure you have air correction hole on side of idle jets, runs rich without air correction hole. I opened the progression circuit holes just slightly on 2nd and 3rd transition hole and i added a fourth progression hole on 40 dcoe, but this is on 1914cc. Progression is smooth and acceleration is available at any throttle position now. Make sure float level isn't high, excessive fuel is easily pulled through auxiliary venturi . ....What size main and airs do you have?

[advinnie]

Hi my jetting
Idles .55 F8’s
Mains 152’s
Vents 28’s
Air’s 180’s
Emulsion tubes F11’s

I have tried 50 idles but although they do give the best idle she runs just a little lean so went with 55’s.
I’ve tried 135,140,145, 152 @ 160 mains and I get the same fault.

Yes I have noticed that the second the butterflies are cracked open I am getting lots of fuel being pulled through out of the auxiliary vents, why is this ?

At idle non of the progression holes are uncovered so at least I’ve got that but right
I’m also running 3psi fuel pressure

[madmike]

If I remember correctly, Mine has a F-11 and a F-7 e-tube combo

[advinnie]

Well some news. I refitted the stock points re timed the engine and all’s good
I’m going to go back to the 50 idles cause the 55’s have made her very soggy and sluggish in the lower rpm limits but as soon as it hits 3000rpm it’s like a switch has been flicked and she’s gains so much more power ( this is off boost)
Now I still have the problem of a 5 degree timing split between the highest and lowers cylinders so at 30 degrees BTDC the lower one is only at 25 degrees BTDC but I’m guessing this is down to the distributor cap?

[madmike]

an F-2 will lean out the bottom and richen up the top

[advinnie]

cheers mate I will give them a go

[rs58rag]

Your floats might be too high, double check and reset. Try bigger main air jets, this will bring main circuit in sooner when you step on it. Also, did you put an oil restrictor on turbo oil supply?

[advinnie]

No oil restrictor in the Oil feed line just a straight hose with a 2.25mm ID union at the turbo end. Will double check the float heights as well.

[rs58rag]

I use 60 pump jets, 65 idle jets, 30 vents on 1914.

[rs58rag]

Do you have a case of spark plugs? If the porcelain area is dark, good chance it's fouled and will misfire/run crappy. Focus on your progression circuit and try to keep idle and pump jets as small as possible. You're trying to supply enough fuel through a long run manifold through some tiny progression holes on a carb that was probably designed to be used as a pair on a naturally aspirated 1300 engine and now you need to feed a turbo fed 1600cc beast! I think I opened 2nd and 3rd progression hole to .80 mm, and added a 4th, need to double check. You won't need to go this much, just a little bit makes such a difference in acceleration and drivability.

[rs58rag]

Just measured... progression holes on carb I'm using are at 1.18 mm.times four holes ......Spare second 40 dcoe had extra .80 mm added. .....Third unmolested spare 40 dcoe has 1.18 mm first hole, .90 mm second hole and 1.00 mm third hole. So just a lititle touch on these makes a difference.

[advinnie]

All sorted fitted a difference 009 distributor and set the ignition unit up to 15 BTDC and cylinders 1,2&4 all read 15 BTDC and cylinder 3 read 14 degrees BTDC. Also went back to .50 idles jets and no pop just of off idle

[buguy]

Do you still have the pointless in there? And running the black box?

[advinnie]

I’ve gone back to points now was using one of those pointless ignition units that fits inside the distributor