Screwy screws

So, both sets of the FJ600 carbs I have are out of commission sue to boogered screws.

One set has a drill bit broken off in a pilot screw, and the other has a butterfly screw broken, and two other butterfly screws (that's one screw per carb body) stuck with stripped out heads.

I am not sure what to do at this point. I don't have the tooling to deal with this kind of thing.

Any suggestions?

 

If you can file the heads of the butterfly screws off then can be removed (work patiently). The broken bit and pilot screw should be abel to be dissolved with....well here's the really cool video
Just be sure to either isolate the solution with a clay dam, or strip the other steel parts from the carb bodies before dunking them.

 

Hey, JPaganel, How are ya doing? I take it these carbs have been sitting around a long time? I'm thinking do you really need to remove the butterflies? I wouldn't bother. As far as the pilot screw, I'm assuming you mean pilot jet, if you boil the carbs in lemon juice you'll be able to take a wrench and remove the pilot jet and replace with a new one.. If these carbs are that locked up I would boil them in lemon juice. It will dissolve all the old gas that has everything locked in. I used a large stock pot and poured in a large bottle of lemon juice. I put enough juice in it to cover 2 carbs with the bank of carbs standing on end. Then I turned the carbs over and did the other two. The hot setup would be having a pot you can drop all 4 carbs into at the same time. I took the carbs apart and dropped everything back in the juice but the diaphrams. Then I rinsed everything off with hot hot water and blew them and off with my air compressor. Carb bodies and all. I'm telling it really does the trick. With the diaphrams still stuck in the carbs I would bring lemon juice to a boil, take it off the fire and drop the carbs in. After the diaphrams are out you can boil the other stuff without worry. There is a website in this forum somewhere that goes into great detail about it. It's the way to go. Hope this helps you, Man.

 

Two of the screws have heads, and I could probably file slots into them. Third one has the head snapped off - I didn't file the peened tip enough. Not sure how to turn that one.

This whole thing started because I cleaned them, and they still wouldn't run, and it looked like an air leak, so I started on replacing shaft seals.

You kinda have to, to get at the shaft seals.

Nope. I mean pilot screw. Also called idle air or idle mixture screw. Also, these are Mikunis. Pilot jets live in tiny and deep wells, no getting a wrench on them at all. You must be thinking of Keihins.

I'm kinda past that point. I'm where I broke a bunch of stuff...

 

Worry about turning the screws after you've popped the butterflys off. The goal here is to make room to work. If the screws won't turn after the throttle plates are off, then you can file them down flush so the throttle shafts can be pulled from the carb bodies. At that point it becomes much easier to deal with screw extraction, and worst-case you have to find a set of junk carbs to pull the throttle shafts from instead of having a whole rack of unusable carbs.

 

How would I pop out the throttle plate if I don't have both screws out?

 

Drill the screw heads off. Use a drill bit that is larger than the shaft of the screw, but smaller than the head so you don't open the hole in the throttle plate. I think IIRC the plate screws are 3mm on my 700, if you have one from one of the other throttle plates that you managed to get out, use that to size your drill bit correctly. You may even have to go back to an SAE sized drill bit because again you want to be just larger than the shaft so that the head will pop off cleanly.

 

as for the pilot screw, I had one the same as you , with the head sheared off ,down in the hole .
I took the body, to a guy that has a "spark eroder", its a machine ,that fires an electronic spark at the screw, and erodes it away, without damaging the threads, then all is left are the outer threads of the brass screw, which are then "picked" out. process cost me £20. well worth it
stu

 

That won't work.

Plates are in a slot cut through the middle of the shaft. The thing under the head is the top half of the shaft, not the plate.

 

Oh dang, you're right. I forgot about the difference in the xj600 carbs. Hmmmm..... It might be machine shop time

 

Shazbot, sorry man I didn't realize the carbs are that different.

 

I was going to suggest machine shop too.

 

I've got a set of Mikuni BS32s (FJ/XJ600)here that I paid 50 quid for. They were supposed to be BS30s and the guy that supplied them wouldn't take them back . They're a bit rough but might be good for spares - wouldn't mind getting some of my money back on them though..

Cheers

J

 

Sorry if I'm a bit late- but if the throttle shafts already may be a loss due to the rusted in screws, why not just cut it as many times as required to get it all out? Then look for a replacement shaft?

 

Throttle shafts for those carbs are difficult to find as a seperate item.

 

They are not rusted. I forgot to grind down the peened-over screw tips.

Neither shafts nor shaft seals are listed as a separate part for this model.

I'm going to show this mess to a machinist friend, see if he can salvage it. If that doesn't pan out, I will hit you up.

 

a100man:
I tried to send you a message but your inbox is full. Did you ever unload those FJ600 Carbs? I have an 85 FJ600 and I am always looking for spares. I don't know what 50 quid is in terms or US Dollars, but let me know.
Thanks
Tom

 

Tom, cleared my inbox. 50 quid is approx 75 USD but I paid too much 'cos I thought I was getting BS30s. By all means send me a message I have now cleared some space.