Van Islander's TX650A - Quest for a Daily Rider

[TX650A Van Islander]

5T, yes, further detective work has found that either screw turns in properly just like your photo, into the right carb only. Attached are photos of right and left carb with screws installed, backed out 1.5 turns. The depth of the hole is identical at 19 mm but the left carb seat is compromised and the tip of the needle is not going down deep enough into the wee centre hole as it appears the seat is mashed. Photos of right and left seat also attached. Perhaps that bent tip screw damaged this seat when used by the PO?
Sucks because these carbs are otherwise in much better condition than the original '74 carbs. Any more ideas? Perhaps just use one of the other screws to turn down through this mess, or perhaps install the carbs and see how it goes?

 

[5twins]

I don't know if the seat is damaged. It looks more like a piece of the needle tip broke off and is stuck in there.

 

[gggGary]

looks to me like you've got the busted off tip of the old needle in there yet.
Look in the front of the carb, is the tip sticking into the bore?
With some care that old brass tip often can be pushed back up and out.
Got that done a couple times.

 

[bosco659]

That’s probably how the old needle got the bend in it. Agree with @gggGary, if you’re lucky the tip will be exposed in the throat of the carb and you may be able to push it back out. Maybe a bit of localized heat near the seat to expand the aluminum to help get it free?

Looks like the brass is twisted. From a failed attempt to remove it or a stuck needle that was strong armed out?

 

[gggGary]

My bad the needle doesn't penetrate the bore on the BS38's that trick is for BS34's.
Let me go look at a BS38 or two.

 

[bosco659]

Is it a bad pic or are the threads boogered in that one carb?

 

[gggGary]

Yeah no reasonable way to get that out unless some real fine pliers can grab pull it up, not likely. You're prolly SOL on that carb. Sorry.

 

[5twins]

I wouldn't give up though. I'd soak it real good with penetrating oil, heat it up real good too, and try to pop or pry it out. Who knowa, maybe once it's been soaked and heated, the bit will just fall out if you tap the body on the bench.

 

[bosco659]

If the carb will become unusable anyway. I’d disassemble it, then give it a good dose of heat in that area, without directly heating the brass. Then maybe try to work the brass nub side to side with a small screwdriver to see if you can initiate movement. Sounds like a challenge - if you ship the carb to me I’d like to have a go at it. But! If the threads are buggered it’s all a wasted effort.

 

[bosco659]

Where the hole is in the carb bore, what’s on the opposite side. Could you drill a hole opposite to the needle hole and get a tiny “punch” to push it out after heating and penetrating oil. Then plug the hole with JB Weld or a threaded plug. Might be a dumb idea - don’t have a carb in front of me to see if it’s feasible.

 

[gggGary]

compressed air here?

Still trying to figure out how they drill that hole.....

 

[bosco659]

 

[TX650A Van Islander]

Is it a bad pic or are the threads boogered in that one carb?

Bad pic. The threads are ok. I had not thought about part of a screw tip being stuck in there. Interesting ideas you guys have - thanks. I'll have to take it all apart again and will have a go at it. Questions to follow I'm sure...

 

[TX650A Van Islander]

Staring at it with 57 year old eyes into a very small hole not that easy. Need to find a magnifying glass. I think you're correct with the thought of a broken off screw!

I suppose in theory its doable to drill into it Bosco where you suggested. What do the brass pins do which are on either side of this screwdriver?

 

[Jim]

They plug holes that were drilled to create the passageways inside the body.

 

[bosco659]

My last crazy idea for the night. Get a blob of solder to bond to the screw. Then get a brass or copper rod (tinned already), stick it in the hole and try to get it to bond to the broken screw. That may give you the leverage you need to break it loose. Once loosened up, heat the carb and parts up to the melting temp of the solder and shake it out or a last of compressed air. Risk of plugging up the passages but at this point there’s little to lose.

crazy idea 2B: get a copper or brass tube that will fit in the hole and with a large enough ID that will slip over the brass piece. Do the solder thing. I was going to suggest epoxy but that could mess things up inside the threaded area.

like this

https://www.sunwardhobbies.ca/brass...MIgvPA6py5_AIV6-bjBx1AfACXEAQYBSABEgIVl_D_BwE

 

[gggGary]

Drill at red arrow, use a small drift to tap out the stuck needle tip from the pressed in orifice at the orange line between the two brass plugs.
finish by shallow drilling the hole a bit larger and glue in a small ball bearing to seal it up.
blue arrow where they drilled the cross bore to the intake.

 

[TX650A Van Islander]

This seems like the best approach gggGary. Thanks guys for the brainstorming. Stands to reason that this mess was caused by the other piece of that bent screw I showed in a previous post. Perhaps this week I'll have an opportunity to do this.

 

[5twins]

I'd exhaust all other possibilities first before I resorted to drilling (heat, penetrating oil, prying against the broken bit). Who knows, with a little persuasion, you might just get it out.

 

[Jim]

Something that's worth a (long) shot....

First, remove the slide so as not to explode the diaphragm. Screw the cover back on.
Take two pieces of metal or plywood and clamp the body in your vise... blocking the inlet and outlet.
Remove the main jet and take a blowgun with a rubber tip... blow shop air into the needle jet.
This will pressurize the inside of the carb body and all passageways.
It's possible this will apply enough pressure on the stuck piece of brass to shoot it out of there.
There's gonna be some leakage at various places, but not enough to prevent pressurizing the body.
I doubt it will work, but it's easy enough to try... give it a shot?

Caution: use full protective equipment anytime you're pressurizing something that wasn't meant to be pressurized.