Spada carb problems, Help.

I am usually quite good at setting up carbs, but am having a few problems here on my Spada, so can anyone help with some advice from experience and knowledge please. I bought the bike as a converted cafe racer so the carb set up, exhausts and filters had been changed - the bike ran well in this set up. So all the starting points had moved fro standard. I have returned the bike to standard spada spec except for the carbs at present, i refitted a keihan Spada exhaust and crossover pipe in place of the straight through pipes fitted on the cafe racer, The carbs run S & B circular air filters (similar to K&N), the jets have been changed from - 125 main to 130 main, the idle to 53 from 50, the float height has been moved from 23/24mm to 25mm. needles remain the same. I have fully stripped the carbs, cleaned and rebuilt them with all new seals and gaskets. (I did try moving the float height back to standard but the bike was running very rich) i have returned it to 25mm for the moment - one adjustment at a time is best i think. I would think the main jets are probably about right with the air filter, but am not sure on the idle jet circuit if that should be returned to standard 50 then return the float height to standard). At present the bike runs but is very lumpy, and cuts out as it runs rich at the bottom end. I have tried turning in the idle screws they are now set at 3/4 turn out instead of the recommended 1 1/2 turns out.( even usng a colour tune the burn is blue and looks right but the transition from idle to 3/4 revs is very lumpy and not right) But the bike is no where near as smooth as it should be and not happy at low revs. I will try returning the idle to a 50 but it would be great if anyone has fitted the S & B carbs to their own bike and could let me know if and what jet changes or needle height adjustments they have made - before i start digging it the carbs again. cheers Brad.

Only thing that needs changing is the main jet size, because of the filters as you rightly say, get everything else back to standard including the float height. If memory serves 23mm is right for 10 grams floats, check they are, the other was 14 grams I think which will need to be at a lower level. Could well be 25mm but never used them.

Thanks Mike, they are the 10 gram floats, I need to order a smaller pilot jet - get that done and hopefully get her going a bit better. On a side note i found that the replacement (genuine dell orto) Choke pistons for the fuel enricher circuit are shorter than the original ones fitted which are also dell orto there is almost 2mm difference in length. Even with the adjusters bottomed out i could get no slack in the cables so do not think the shorter (new) choke pistons would have sealed the enricher jet).

Thanks very much for that feedback on the other jet and float settings . regards Jake.

Are you sure it’s not a timing issue?? Try strobing it at 5000 revs to look for the full advance marker. Don’t rely on static timing, or tick over on the 1st marker.

Hi Don thanks - i will recheck the timing once i have gone over the carbs, maybe it had been moved a touch to suit the running of the bike, its something i have not yetchecked.It was running fine until i changed the exhausts, which are a lot more restricted than the ones that were fitted which were simply empty chrome exhausts with no baffles, no sound deadening nothing at all - so that is bound to play havoc with the fueling once i junked them and put a standard baffled system back on. The timing however is well worth a check . Thanks for your input and advice. Cheers Jake.

My Spada run’s K&N copy type filters on it and Armours silencers which do have some baffling in. I am still on standard jetting, I’ve never found a need to change it.
It’s worthwhile checking the choke plungers are dropping fully down and seating on the opening at the bottom, check the rubbers at the bottom of the plungers are in good condition.
I assume you do still have the original square slide carbs fitted?

^ wot he said re choke plungers and their seals.

Also I forgot needles, clip in 2nd notch from top of the needle, I think. Also remotely possible the needles were changed for different spec., along with the other changes. (?)

Standard is V9? (can someone confirm)

Hi Just to let you know yes the needles are V9 and are on the 2nd (middle clip position), i have checked all the spec on the carbs again, and today fitted the new 50 idle jets and reset the float height to 23mm, but do not have time to start running and setting up the bike due to other commitments at the moment (ie of on hols in the morning). When i rebuilt the carbs i found the new and correct part number del orto replacement plungers were 2mm shorter than the originals so i was unable to adjust the cables low enough to allow them to seat properly. I have now turned the rubber seal around in the originals so they are like new and refitted the originals they are sitting fine. I am now back to original spec starting point except for the 130 main jet. So will see where I get from this point when i get back home. Cheers to everyone for the input. Jake.

I would screw out the idle adjustment screws to 2.5 - 2.75 turns so you really are sure that the idle circuits within the carbs are properly in play. They can be screwed back in a bit later on when you are fine tuning.

Thanks for all the replies and advice, the Spada is now running really well, the carbs are set up and the main issue turned out to be a lot to do with the timing as per Don Spada’s advice. I ended up fitting a crank driven electronic ignition that has transformed the bike at all revs. Once this was fitted getting the carbs done was a real simple task. Now i need to find a way to lower the footrests and brake lever as I feel the seat to foot peg height is just to tight, these are really built for people with shorter legs than i am currently in possession of - any ideas ?. Cheers jake.

Glad you’ve got it sorted. Problems like that can be very frustrating to get to the bottom of.
I too have recently found the seat to footrest position quite short. Never noticed it before in many years riding just the Spada, but now I have a bought an old Bonnie, the two are way different.
I get on the Spada after the Bonnie and look for the footpegs where the brake and gear levers are!
If your’s is an early Spada, then the later Spada NT or T3 footpegs (the cast ones) are slightly differently positioned, but it’s not much different. I doubt you would barely notice it.

Cheers Don, I may fabricate some lower footrests and re-manufacture and re-model both the gear and brake lever to allow them to work in a lower position, maybe do that after the summer though as want to get some miles on the bike at the minute, I may also even have the seat built up a tiny bit hopefully be able to keep the looks fairly similar but gain a bit more leg room. Jake.

The early Spada seat is a bit of a plank, the later NT had the Convert seat, about 2 inches higher and way more comfortable.

cheers duffo, i will look at that.

I’ve just went through the same type of experience with my T3. Rebuilt carbs, returned everything to standard settings, had them ultrasonically cleaned, then played around with different jetting to suit S&B type filters and armours stainless silencers etc etc… only to find out it needed a new set of points and timed properly at full advance. If I had read this a month ago would have saved endless work. :neutral_face: