TOPIC:

I tend to agree with Pete (Strate6) here. You've blocked off the air access to the air injection reed plates and also the air feed from the air box so you shouldn't have any popping from the air injection system. So Scotch is probably right as well with his conclusions that you've got a lean idle condition in 1 or more carb circuits and/ or an issue with the idle jets. Finicky little bastards. Well worth replacing the jets for the cost if for nothing else, to remove that possible issue from the equation.

I would also seriously consider buying one of Scotch's flushing tools. The only way to clean out that idle circuit is backwards through the circuit since the smallest end of the passages is at the bore of the carb. Trying to push the crap out of the circuit in the same direction as the flow of fuel in that circuit will just plug the small end of the circuit. All it takes is a fleck of crap about .015" in diameter to block 1 of the 3 idle passages and then you're into trouble. Scotch's tool is specifically designed to back flow this circuit and I give him Kudos for coming up with the design and making this tool available to us for a reasonable price. I'm sure lots of our KZ1300 carbs have been brought back to life thanks to "Scotch's Flushing tool".

KB

This is a typical situation where an issue - "popping and backfiring" - can be caused by one or more deficiencies. In this case, The popping is likely due to blocked and or OLD idle jets and the backfiring possibly being caused by an air-leak in the reed box for the Air pollution system as kawboy hypothesized.
Both are easily rectified. Replace the idle jets if not already done ! I've previously discussed this so won't elaborate further. With the reed boxes: remove the cam cover and block the ports in it. Blocking these ports is easy and will guarantee there are no air leaks into the exhaust. There are various ways of blocking the air injection ports (in the cam-cover !) but the easiest IMHO is done by the following: Thoroughly clean the ports in the cam cover with Lacquer thinner and a long/round wire brush. Use one with S/S or brass bristles !


If you cut-off the end-ring you can spin the brush in a drill and guarantee a proper cleaning.
Then, place some tape over each port in the cam cover on the gasket mating surface and fill with J.B. Weld High Strength Metal Filled Epoxy. I did this years ago and after 20 yrs. (?) there was no degradation of the epoxy. The cam cover doesn't get hot enough to bother the epoxy despite the ports in the cyl-head being left open. There is no need to do anything further.
This may be the time to clean-up the cam-cover by removing the "Reed Boxes" completely. Can be done easily with a hack-saw. Don't attempt to cut them off 100% flush. Leave 1/16" and file down the rest to ensure a nice finish, with no hack-saw marks in the cover, over-all. If you decide to remove the reed-box housings then you can do the epoxy treatment after their removal, which will be even easier. The advantages of removing the reed-boxes are: Neater/cleaner appearance and it makes removing the cam cover so much easier !!!!!!
hope this helps !

SCOTCH......

Can you please send me a PM with details and pricing for one of your special carb tools as mentioned above?

Postage would be to the Rear End of Europe (The UK).

Thanks

Pete F
UK (or whats left of it).

Hi Pete !
I'll address your inquiry here, so others will know the procedure.

To expedite an order for Brass Floats and/or a Cleaning Tool - Send me a P.M. with your full name and mailing address PLUS your email address. I will then send you a PayPal invoice including the cost of mailing, for your approval. I usually get an order out within 24 hrs. of payment.
I currently have 4 Cleaning Tools and 3 sets of Floats, in inventory.
An order for a set of Floats AND a Cleaning tool, is discounted 20% - which can cover a good portion of the mailing costs, depending on where on the planet you live.
You have the option of "with or without a tracking #" but the parcel is mailed via Canada Post Air Int'l., regardless. Parcels mailed within Canada are OK
shipped "Surface".

Thanks, in advance, scotch

....not sure what you mean by the "reed boxes"
the cam covers have two holes one on either side and both facing back towards the carbs...
they are both blocked of by a large chrome dome nut each, held in place by a silastic glue....
is there a photo or a diagram of what these reed boxes look like....?
excuse my ignorance....

Your valve cover probably has two of these covers on it's top:

Underneath each of those covers are one of these (reed valve):