There are several things that will cause popping,erratic firing.Most of it's covered in the Carb section but for now.
Outside the carbs.
At idle spray the WD40 around the carb boots.If the engine speed changes there's a leak to be sorted.I had to replace the Jubilee clips on one of my CX because although they looked good they weren't clamping correctly.
http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=17&t=76&p=367&hilit=jubilee#p3672nd.Any leaks out of the engine in the exhaust or collector box will cause popping and back firing.
Once you know the fuel/Air going in is OK then it's internal in the carbs.Proper deep cleaning of the carbs is paramount to their correct running as it setting the correct float heights.
http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=19&t=140http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=19&t=110Commonly overlooked when cleaning the carbs is removing the,"Black Banana" in the top of the carbs and flushing and high pressure air blowing the slow speed circuit/holes.These cause no end of problems if there's a blockage.
You should also fit an in-line fuel filter(Dead cheap)
http://www.toolparts.co.uk/acatalog/Fuel_Filters.html2nd from the left the small white ones are the ones you want.6mm round filter £0.99p
You can get them off Ebay as well but I also treated myself to a bit of their fuel pipe which is way better than standard stuff.It doesn't rot or degrade and the extra bit left over has been invaluable for bleeding brakes
Worth getting a couple to save on postage if off Ebay.Not fitting one and all the good work done cleaning and setting up the carbs can be undone in an instant if even the tiniest bit of crud gets back through.
The ones I use are similar to the link and I've had them over four years and just forward and back blast the from time to time with Carb/Brake cleaner and they are still like new.I rarely get any carb problems once they have been cleaned and setup and these fitted.In fact I re-cleaned my main CX carbs last year and that was only the 2nd time in over 4 years and it turned out to be the Above Jubilee clips that were causing the problem and not the carbs themselves.Doh!
That should give you enough to do for now
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Hi everybody from Lancashire in uk,my bikes are a 1953 sunbeam s7, vn750 and cx trike ,bit of trouble with the cx at the moment but sorting it out with the help of this great forum.
Hi all,
this time cheers.
Hi guys,I cleaned the carbs,found the fixed jet blocked (under the rubber bung)well pleased with the cleaning, when I put the carbs back, still popping. checked all the joints with wd40 was ok,I happened to move the carbs slightly and noticed a fine crack around the rubber manifold in the corner below the jubilee clip. Did the same check this time with easy-start moving the carbs slightly engine speed increased so I have to find a way to seal it.