so iv only just bolted my manifolds and exhaust and #OOPS# togeather first eveer fire and it started made me real happy but it revved real high to start with (probably the EFI in a can i used) i dont have the throttle cable attached as the stock one is too short but when i rev it the pistons in my SUs dont lift ? any help on the matter? il have a further play

It really depends on how long you rev it for, how hard, and so forth. They don't (and shouldn't) move massively quickly. If you opened the accelerator to maximum in neutral, then it would hit redline rpms at around the time it visibly has only lifted the pistons probably `1/4 of the way up. There really isn't that much travel in such a short time. I'm assuming they've got something approximately like auto trans fluid in the dashpots.

I'm also assuming that if you stick your finger in the carb mouth (engine off of course) that you can lift hte pistons by hand.

When they are cold, they move slower. As the engine warms up and the oil thins a little (heat is conducted out through hte manifold to the carbs) they'll move a little quicker.

Failing that, if you really think the oil is too thick (and trans fluid possibly is) then you can try sewing machine oil instead.

IF HOWEVER they don't move up and down smoothly when you try and move them by hand, then something IS wrong, but it isn't necessarily a big drama to fix. The jet on an SU is fixed, but it can actually be moved. What you need to do is centre it by taking it apart, dropping the jet out then undoing the jet/mixture adjuster nut all the way down so it comes off and the spring sandwiched between it comes off too. Then you crack open the nut just above it, this will actually allow you to move the centre of the jet retainer around, until it is directly centred under the needle. So you re-fit the jet and hold it up there by hand, and drop the piston all the way down, so that the thick end of the needle helps you centre the jet and you re-tighten that upper nut. Then drop the jet back out, re-fit the spring and mixture adjustment nut. Once they are added on, even at their highest adjustment, the jet will sit a fraction lower than where it could reach when you centred it, so it'll now never touch the needle and never sieze).

If THAT isn't the problem *(and I guess you should check this first acutally) it's possible - since they are alloy, that some oxidation has taken place. remove the bell shaped cover, and pull out the piston, and check for corrosion. If there is some, use kerosene and scotchbrite, and clean all surfaces that slide on each other. It should free it up. If the corrosion is worse than that, clean it with a brass brush on a grinder or drill, again using kerosene as a lubricant. If that doesn't work, then and only then gently polish the piston in the areas that contact the inside of the bell cover (and the inside of the bell cover itself) with very fine 800 grit wet and dry.

thanks mate i think the oil might be a bit thick im using auto trans fluid but its been like 4degrees here over night and top daily temps of like 12 so i might hut though mums sewing machine stuff and find some oil.

when it starts it idles a bit high with the pistons being open a bit but then when i open the throttle leaver it drops the bottom pin but the piston wont rise at all and when i rise the piston by hand the revs dont change ?

When you say it drops the bottom pin when you pull the throttle,I'm not sure what you mean, but 'maybe' just maybe you are actually pulling on the choke mechanism, which has a linkage which will open the throttle blades a little but simultaneously shift the jets downward so it goes well rich. Any chance that is what is happening? in all seriousness, the linkages can look confusing, so you wouldn't be the first person to do it.