carburettors

[phil1]

Hi all friends, in particular the mark series. I have just noticed on replacing my throttle slides for the mark v carburettors no,274AJ/4A and 274AK/4A the said slides do no fully retract on the back side of the slides thus leaving the air intake partly restricted ? This is very unusual compared with other Amal carburettors and I am wondering if there is any particular reason for this. Any suggestions would be much appreciated. Phil.

[eddie]

Phil,
       From your description, are you saying the bottom of the slides still project into the bore of the carb when they are fully raised? If this is the case, make sure you have slides for a 274 carb - the slides for a 275 carb are the same diameter but slightly longer, so would hit the top of the carb before lifting clear of the bore.

  Regards,
                 Eddie.

[phil1]

Hi Eddie thanks for the info, it appears I have incorrect slides! They are marked 4/5 but should be about 1/8"shorter in the body length, I have just re- made these in the workshop so I will have to set up and cut them back!! Apart from that the bike is going very well. Regards Phil.   

[eddie]

Phil,
       If you are going to shorten the slides that you have, try making the cutaway about 1/32" shallower - that will give a slightly richer mixture on pickup from tickover - the richer setting seems to suit our old Duggies when running on unleaded fuel. I have also found that an increase of 5 on the main jets helps to control the temperature when working hard.

  Regards,
                Eddie.

[phil1]

Hi Eddie I will get my slides sorted! I thought there was something amiss but wasn't quite sure I was on the right track, so many thanks, now I just need to stop those carburettor intakes going up my trouser legs!.  Regards Phil.