Re-use butterfly screws?

[KA1J]

I'm going to rehab a set of XJ11 carbs. I had no problem getting the old butterfly screws out after grinding off the mushroomed ends. I've read about replacing the old screws with new ones & using blue locktite when replacing them. I'm wondering why I'd need to get new butterfly screws since the blue locktite won't do any good on the exposed threads of new screws.

Seems like I should be able to use the old screws again.

Any past experience with this?

Thanks

[BA80]

I've always reused them. I wouldn't know where to get new ones anyway.

[KA1J]

Thanks BA, that's what I needed to know. Dropping them in the dip tonight.

[skids]

You might want to keep track of the plates with the respective carbs. On install, it might help to install the screws dry, close the plates to check proper alignment, then only remove one srew at a time for the Loktite to keep the plate aligned.

[BA80]

+1........good point skids. Those plates have to be centered properly. Although I've never had an issue with using plates from different carbs as long as they are properly centered.

[KA1J]

A good point indeed. I've always guessed there may be a degree of seating seeing as aluminum and brass are both so soft. If there is it might be best to keep everything in the same place. I did notice the numbers on the butterfly are all in the same place (lower front) which helps orient the butterfly when putting it back.

[BA80]

There is also an angled edge and actually they will only go in there one way.

[KA1J]

That's a help, there's always enough to be confusing so all pointers are good.

Funny, I had to grind down the mushroomed tip of the screws to be able to unscrew them (& even then I had to brace the inside of the shaft and put all my weight onto the screw to turn it free without stripping the head) but I was sent a junk set of carbs from one of the early XS11s, one with the brass floats. Two of the butterflies were removed and the throttle shafts removed as well with three of the original butterfly screws screwed back into the shafts. What's interesting is whoever removed them did not grind them down & the impact dot remains at the tip of the screw.

Somehow he got the mushroomed tip out without stripping the head of the screw. Amazin'... Maybe he stripped the 4th one but the three returned to the throttle shaft look great.

[BA80]

Sometimes they will come out without grinding. The trick, sometimes, is to get them to go back in.

The staked ones I've removed before by just working them back and forth. That's even better because if/when you get them started back in they have an interference thread that won't work loose. I can't remember ever having one come loose before though.

[KA1J]

Interesting. I didn't try to wobble them out, was afraid I'd damage the head when I met resistance.

I wanted to protect the carb so I made a 1.5" wide strip of epoxy putty that fit inside the outlet. I put oil on the outlet so it wouldn't adhere & when solid I easily pulled it out & then ground the edges so it fits inside & I place it midway above the screw tips. & if the dremel tip runs to the edge it only hits the epoxy barrier instead of where the butterfly meets the aluminum. When done, replace it in the next carb & then down the line. Worked great. Would have been better to be able to just safely unscrew them as you do.

[BA80]

I didn't try to wobble them out

huh? That's not what I said.

[KA1J]

huh? That's not what I said.

True, I understand what you meant & wobble was not the right word to describe "back & forth" rotation. Sorry about that.

I found the screws are made from softer metal than I expected and they deform easily so it takes a fair amount of downward pressure to get them to rotate without munging the slots. You've got a better touch than I do to back & forth them out & not damage the screw head. I'm using a JASO #1 screwdriver, maybe a #2 would be better? Seems to fit snugly though.

[MPittma100]

Be Safe

To be safe, I recommend using "red" Locktite rather than the blue. I am curious - Is it necessary or why is it necessary to remove the throttle blades?

MP

[skids]

to replace leaky throttle shaft seals

[KA1J]

to replace leaky throttle shaft seals

Indeed. If you carb dip they will be ruined and all of these were really brittle when they came out. Minus all things rubber and plastic you can safely dip them. When I removed and dropped the old seals on the table they clicked, When new they're like thin "flat" O rings and they quietly bounce. Stiff like these were, the next thing is an air leak past the throttle shaft and a carb that won't tune properly.