The part numbers are different between the A and B series 1000 carbs. Does anyone know why? As my next carb project I'm considering the carbs linked below. The closest match I can make is the 1979 KZ1000 B3 carbs which are unique according to the fishe on Partzilla.
Do the B series LTD carbs use VM26's instead of the later A series bikes that used 28's?
The only thing I can verify is the B1, B2, and B3 1000 Kz came with VM 26 SS carbs. The 1980-B4 came with the VM28 SSmm carbs with accelerator pump. My Eyes see the above posted carburetors as version 26. Compare the included photos of the bore proximity of the pilot air intake orifice
EDIT, I think that is the enrichment air jet.
Correct me if I'm wrong but don't the VM26 and VM28 carbs use the same carb boots? The PN's seem to be the same. Anyway, the outlet flange thickness seems thinner on the 28's, and the carbs linked earlier have thick flanges so I agree they look like 26's. Makes sense; the LTD bikes are cruisers compared to the more performance oriented STD bikes, so it stands to reason that they would use smaller carbs.
VM26SS carbs were used on all 900/1000 models from 1976 to 1979 except the Z1R (1978) and the A4. Over that time frame the internals were downsized to improve fuel emissions, particularly at idle. By 1978 they were so lean that the bikes had issues from a standing start. The pumper version was introduced to improve takeoff in mid 1978. Matt can chime in on whether they used it in 1979 on the LTD. In 1979 they upped the size to 28 mm with a pump and used it for the A4 and all 1980 models except the Z1R.
Yes, the boots are the same, which means the 26 mm carbs have thicker outlets.
I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.
The 1979 KZ1000A3, the standard MKII used the 28mm and also the 1979-1980 KZ1000E1, E2 shaft drive. The only 79 that didn't have the 28mm was the LTD. Not sure why, but the 1979 LTD was also the last KZ1000 to use points ignition after the rest had gone electronic. I always figured they were using left over parts for the less desirable model, that seemed desirable to guys that were more or less Harley riders, but desired a better motorcycle in reliability.
321,000 miles on KZ's that I can remember. Not going to see any more.
As i said the problem is the second diaphragm, if that part is disabled and bypassed the pump acts the same as the 28s and are completely tunable, i doubt any of the carb re-builders will do this mod when they do the re-builds for paying customers.