1st 626/66 2nd 626 72 3rd 626/73 anyone know what they were originally off?
the slides are 3and a half
Your T160's engine/frame number? /72, /73 are standard early T160 carbs, originally fitted with 3.5 slides and 'short' needles (two faint rings engraved around the blunt end above the top clip groove); it is only later T160's that have /76 and /77 carbs with 4 slides and 'long' needles - five rings around the blunt end.
Before I play Hunt The Carb Number for /66, is correct, not a typo?
little collett thingy and spring is still in the slide
return spring on the gantry
/72, /73, /74 carbs were fitted with the small spring and upper "Retaining cap" (no.6 in the parts book) on the Throttle valve rod because the carbs did not originally have a slide return spring in each carb (why one is not shown in the parts book) to tension the rod in the slide and retain the needle. Because each carb did not originally have a slide return spring is why there is a return spring on the gantry.
bought three of the light throttle springs correct part number and they are about an inch longer than the ones in the carbs
The lighter slide return springs were fitted to later T160's (/76 and /77 carbs), none were fitted to /72, /73, /74 carbs.
If you fit the new slide return springs, dispense with the return spring on the gantry and the small no.7 Retainer spring and no.6 Retaining cap in each carb. However, keep the no.9 "Retaining plate - needle clip"
on top of each needle clip (not as shown in the parts book) - stops the needle clip becoming entangled in the slide return spring and causing a problem that requires dismantling the carbs ...
As standard, all Concentrics seem to run rich at low rpm, leading many owners to remove the chokes, particularly if the ambient temperature is generally high. However, if you set up the low rpm mixture properly, you could find the chokes useful while the engine's cold but running.
If you keep the chokes, carbs assembled, lift each no.5 Throttle valve fully, check the no.26 Air valve is not visible in the carb's main venturi - happens when the choke cables stretch.
If you remove the chokes, Amal make a blanking bolt with the correct thread for the carb top - part 4/137.
any thoughts and what runs better, the t150 style air filter set up or the stock t160.?
Standard T150 was 3.5 slides, two ring needles. Also, the T160 airbox is ugly (but, if you have one, store it carefully, costs a king's ransom to replace, because so many were junked 'back in the day').
opposite the mixture screw where the air screw is blanked off, how is it done at the factory?
Concentric bodies are cast with a 'lead' for a drill in each side. Only one was actually drilled and tapped for the
air screw (only varies the pilot air); the fixed pilot fuel jet was pressed into the body.
blanked off with a allen head grub screw. is that factory?
If you mean, on each carb body, the cast drill 'lead' on the far side from the air screw has been drilled and tapped for a socket grub screw, this was done long after the carb left either Amal or NVT, when someone wanted better access than the air screw hole to inspect, clean or replace the original pilot jet. New Concentric carbs are drilled and tapped for both air screw and removeable pilot jet.
