After hours of having my screw driver in hand and listening to my SUs
suck, I broke down and bought a gauge to balance the carbs. Does
anybody have any idea what the suction should be (PSI)? I set it at
7 because it seemed to smooth out there but I don't know if that is
right. It still is a cold blooded bugger but runs great once it is
warm with your occasional cough in a corner. Any help out there?

Don

sorry don, i have no practical experiance of your exact situation, but everything i know about carb balancing says to me the balance of the carbs is more important than the reading itself. And everything i know about SU carbs says get them at the point where they smooth out. I would guess you are about there, but like i said, i could be wrong :blush:

Thanks Big Ben,

After chugging around town for a while, I think that I am close. The cold bloodedness I can live with since driving a 122 I couldn't be in a hurry anyway. I really appreciate the response, I think I am the only person in town still driving a 122s and advice is hard to come by.

Don

1/2" hose about 15 inches long, remove air filters. adjust front carb to the smoothest you can get, listen to the tone of the front carb through the hose, adjust rear carb to the tone of the front. RPMs should be about 1000 to do this.

Run the revs up and see if the carbs are running a simlar tone and the lift is the same.

Done.

If they don't seem the same check needles and seats for anything that might make then hesitate and repeat.

Thanks!

I will give it a try. I am still low on the learning curve on this interesting little machine. It is great to have folks out here willing to share info. The 122 runs well on the road but still has a pretty good miss when it is cold.

Don

Hi folks, if you click HERE you should get the page of tips for tuning SU carbs. So far all i can tell is if the balance if right and the mix (jet setting) is ok all you can do is swap the needles, i need to sort out my 122s (1800cc) cos it only gets around 20 mpg.
hope you find something to help

driud,

Thanks for the helpful info. The balance on mine sounds right and tests right for vacuume, but when I compare the color of the spark plugs the front two are a nice gold color and the back two are a cruddy black. I sometimes need the choke for more powerful starts from stop lights. I also get a lot of condensation our of the tail pipe when I first start it in the morning. I will print out the info you sent and go back in for round two.

Thanks again!

Don

Oh,

By the way druid, Nice Car! :thumbsup:

Don

sounds to me like a leak in the manifold ? or the rear carb is rich, you could try winding the jet (s) up into the carb untill the top of the jet is touching the piston but not stopping it closing (check with the air filters off) then wind them back (anti - clockwise) 15 flats of the nut. Now the fun bit lift one piston 1mm and see what it does to the revs - if it dies its lean (wind it out rich clockwise) if it rises and stays high its to rich so wind it in but always both carbs the same amount. the perfect setting is when the revs rise a bit and then drop back to the original speed.

I had a big headache with mine only 18/20 mpg! (petrol up to £1 a litre) but now its back to 25/28 ish
Have you checked the timing? do you have an unleaded conversion or do you use an addative, the book said 17 to 19 deg for my car but 'cos it on unleaded (i have a conditioner in the tank) i had to back it of to about 13.deg and its a much better car to drive

Hello druid,

I am just using the additive right now. I hope to do a conversion some day.

I will get my screwdriver out and go into the carbs for another round. I have very little experience with the jets and it is all an experiment with me. Thank you for the help and advise. There are so few 122's in this area that it is difficult to find someone with experience at this.

Don