CWB wrote: I have a couple of issues needing attention:
The first is on the butterfly valves on 1982 kz 1300 there are two phillip screw holding each valve in the shaft slot. The butterflies need removing for cleaning but some of he phillip screws have previously been burred due to poor fitting of driver and the screws being bound. Any advice on how much pressure can be applied with bench drill press or other method. Does applied heat help?.
The second , I see in one of Scotch's carby pics there should be a plastic .021" washer under each diaphragm shaft...none on mine. Any advice on where these could be located and are there substitute washer materials that could be used.
Thanks Bill
If you look through the throat of the carburetor, you'll see that the screws are peened from the back to ensure that they don't fall out. Scotch's advice in the past has been to never attempt to remove those screws and that replacing the square ring seals on the shafts is not advantageous. If you do decide to remove the butterflies know that the edges of the butterflies are cut on an angle so that they fit completely sealed when the buterflies are shut. If you put them back in backwards, the carbs will stick closed and the butterflies will start cutting a groove in the throttle throats which will worsen the issue. Removing the butterflies is not something that should be tackled by individuals who haven't been taught how to do this without getting into trouble. I did do it on my carbs to replace the shaft seals and it took me about 4 hours to pull the screws, replace the seals and reset the butterfly plates and I've probably rebuilt over 500 carbs in my career as an automotive mechanic.
Also, this is a good opportunity to point out that the "screws" including the ones you're talking about are JIS screws (Japanese Industrial Standard ) screws and not Philip head screws. They take a specific screwdriver to fit the cross slot. If you haven't got a set of JIS screwdrivers, spend the money and get a set. You won't regret it.
JIS screws have an indication on the head of the screw that looks like a pin punch mark to indicate that they are JIS screws. Philip head screwdrivers will almost fit JIS screws but seem a little sloppy in the head of the screw and a JIS screwdriver in a Philip head screw seem s little tight. It's a small difference but when you're trying to remove tight or frozen screws, it makes all the difference in the world. The reason you have bitched screws on those butterflies is because someone else tried to remove those screws with a Philip screwdriver and mashed the head. Had they used a JIS driver, the JIS driver would have turned out the screws even after they had been peened. When you have the proper tools for the job, the job goes easy. I had carb rebuild training as part of my apprenticeship for auto mechanic and it is a skill that most backyard mechanics don't recognize and unfortunately, you are the victim here of what happens when somebody tackles a job without the experience or training.
My advice for you at this point would be to leave the butterflies alone and not worry about removing them for cleaning or seal replacement. Attempting to drill out the screw heads will not release the butterflies that are pinched in the slot of the shafts so that means that you would have to drill the screw out completely in order to remove the butterflies. That would mean tapping the shafts for the next size up which would weaken the shaft. ( I hope I've made my point here)
As far as cleaning- Autosol and a q-tip will make them nice and shiny if that's the end goal.
Regarding the plastic washers- I have fabricated them before out of old reed plates from 2 stroke reed valves since that material is designed for soaking in gasoline. I found reed valves with a .022" thickness. It was tricky but I pulled it off. (someone else on the site needed one and I made it for them) I'm pretty sure that the last house move caused me to reconsider all of my "spare parts" and I've probably tossed the old reed cages for lack of storage in the "new place"