Air Suction System.....HELP PLEASE

I aquired a KZ1000 LTD, DOM 12/78
It backfires something awful on decceleration.
My Clymers refers to this system with its reed valves and such. Is this neccessary? still avail?
Able to be by-passed?
ANY input would be greatly appreciated.
Vern

The symptom you describe is often caused by the air-suction-system, ASS, (so named by Clymer as a joke, I think... ASS?) .

There are many threads on this subject, but what it comes down to is that you can just remove the gizmo on top of the engine and plug ALL of the ports that connected to it.

Do a search for some tips and methods of blocking the ports. The reed valves should stay in because they have the rubber seals attached to them, even though the reeds will no longer function.

This system should not be confused with the crankcase ventilation system. The crankcase vent is the port on the transmission and must not be blocked.

My solution to that mess is to find a Canadian casting rocker cover from a 79 0r 80 MKll or LTD .No EPA,no polution ports up here and it bolts right on to the US model head...Don't have any on hand at the moment but I've sold a few to KZR folks and everyone was happy.

back fires are caused by a couple of things.
1. leak at the exaust port of the head
2. leak at the vacuum port spigots or carb mount
3. a overly lean pilot circut plugged jet/carb circut orafice.
4. you might just need to richen the mixture screws-maybe

5. the exaust emission has a vacuum hook up connected to a diaphram,if the diaphram has a tear- there is a cause.
6. same with a vacuum fuel tap diaphram if you have one
7. points setting if you still have them
8. finally but not likely a tight valve that is not sealing completely.
take off the tank and have a good look around.

Thank You, One and all for the input.
I will thoroughly inspect & make sure all is removed and plugged. And, consider another cover if that doesn't work.