Carb Air Vent hole cracked

[ChinCactus]

Good luck! Show us the finished repair.

[wedge]

Originally Posted by carbonizedeyesockets

Hey all! Some reason I wasn’t getting updates on this one. Thanks for the input!

Ok that’s wise to grind it. Am I looking to make it smooth for a good JB contact or like is it like I should be cutting it back to make it one angle. ?

When you say tube, are there aluminum tubes I could buy? Or what do you mean?

Any chance anyone knows the size? I suppose I can measure it easy enough I don’t know measurements like this very well thought might ask in case its common one.

Thanks all

I assume you are talking about grinding before epoxying the tube in place. No, you do not want a smooth surface, you want plenty of roughness (called tooth) to the surface. the main reason to grind it a bit is to clean the surface good before epoxy. Take your time, pull the carb apart, get some aluminum tubing from your local hobby shop like Iron Mike mentioned, carefully enlarge the hole with a drill to the size of the tube OD. Cut a short piece of tube (careful to keep it at flange level when installing so you will have less to take off to resurface it) and smear a bit of epoxy on the outside of the tube, place it in the hole, then add epoxy around the tube to mold a clean shape around the tube. After it sets up good, use a smaller drill bit (by hand) and clean out any epoxy you may have allowed to get in the passage. Resurface the epoxy where the mounting surface is using a coarser file to rough carve it and a finer file to finish it off and it's done. Pay attention that the gasket or carb does not block that hole off or the carb can't draw fuel from the bowl when engine is running. Make sure when you resurface that you do not make the mounting surface uneven (wavy). It needs a clean seal or you will get a vac. leak.

Hole size is not rocket critical, it's just the bowl vent. A very important vent but still just a vent. Just get tube that is approx. the same ID as the hole was. Save the rest of the tube. Like most of us, you will end up with a selection of tubes, springs, screws, etc. They will become useless clutter until you decide to throw them out. Then I guarantee that your next job will require something you just pitched out. Or as always happens too, you won't be able to remember where you put it and you will still have to buy another one. Then you will find it, probably as you look for a place to keep the new scrap.

[60Gunner]

Originally Posted by wedge

I assume you are talking about grinding before epoxying the tube in place. No, you do not want a smooth surface, you want plenty of roughness (called tooth) to the surface. the main reason to grind it a bit is to clean the surface good before epoxy. Take your time, pull the carb apart, get some aluminum tubing from your local hobby shop like Iron Mike mentioned, carefully enlarge the hole with a drill to the size of the tube OD. Cut a short piece of tube (careful to keep it at flange level when installing so you will have less to take off to resurface it) and smear a bit of epoxy on the outside of the tube, place it in the hole, then add epoxy around the tube to mold a clean shape around the tube. After it sets up good, use a smaller drill bit (by hand) and clean out any epoxy you may have allowed to get in the passage. Resurface the epoxy where the mounting surface is using a coarser file to rough carve it and a finer file to finish it off and it's done. Pay attention that the gasket or carb does not block that hole off or the carb can't draw fuel from the bowl when engine is running. Make sure when you resurface that you do not make the mounting surface uneven (wavy). It needs a clean seal or you will get a vac. leak.

Hole size is not rocket critical, it's just the bowl vent. A very important vent but still just a vent. Just get tube that is approx. the same ID as the hole was. Save the rest of the tube. Like most of us, you will end up with a selection of tubes, springs, screws, etc. They will become useless clutter until you decide to throw them out. Then I guarantee that your next job will require something you just pitched out. Or as always happens too, you won't be able to remember where you put it and you will still have to buy another one. Then you will find it, probably as you look for a place to keep the new scrap.

Haha! This is why I end with so much 'junk'. Forgot where I put it and buy more 'junk'! I bet I have enough 'junk' to start a small hardware store.
CRS is a b!tch!

[rocketmangb]

Most of my "JUNK" is actually sorted and stored

[wedge]

Originally Posted by rocketmangb

Most of my "JUNK" is actually sorted and stored

So's mine, but do you know where I stored it? Neither do I.

[wedge]

Originally Posted by 60Gunner

Haha! This is why I end with so much 'junk'. Forgot where I put it and buy more 'junk'! I bet I have enough 'junk' to start a small hardware store.
CRS is a b!tch!

I could put Home Depot out of business worldwide if I can only remember where I stashed my junk.

[rocketmangb]

Even my nuts and bolts are relatively "sorted"

[carbonizedeyesockets]

hi all. a little update.

I wasn't able to find small diameter and thin aluminum tubing. I figured I would seek out a form for the repair and that the form would need release. I decided up on a 20D common nail with 3 layers of electrical tape to get the perfect fit for the broken carb air hole. Then I wanted to test options so (not on the carb!), I put a thin layer of aquaphor (cause I didnt have vasoline) on one taped nail and then tried red line assembly lube on another nail &tape. Mixed up the JBweld and had a go. Waited a full 24hrs and check back, to my joy both of the tape nails slide out for test. The assembly lube was easier to clean so I decided upon that.

So thats what I did. I got a new nail, 3 layers of tape, put a thin amount of redline on tape area where i didnt want the JBweld to adhere, placed it into the carb hole, and with fine paper edges and a q-tip made sure to clean off the area the weld needed to contact with aluminum carb body. Now this was the gamble part i think, either i over do it and it doesnt hold or i under do and am stuck with a nail in the carb! Anyway did my best surgical cleaning, said F it and had a go. Came back 24hrs later expecting the worst and it pulled out without a hitch. Cleaned it off, hand filed excess JB down flush with the gasket and here we are.

https://ibb.co/9Yyy8J6
https://ibb.co/FWbPYvf
https://ibb.co/71FVXcN
https://ibb.co/JFzjW84
https://ibb.co/9GdByxr

The good news is that I think that part is repaired.

Now my problem is I also cleaned the carb, replaced gaskets, accel pump, went to a 45 jet, and to SS hex bolts. It'll start with enricher full out, 15seconds and enrichener 1/2 dies. First mix was at 2 out. then tried to 1 1/2. tried upping the idle gradually on both since it sounded so low. I dont have a tach . But maybe I should be going to other way to richen it if its running w enrichener hmm. Off to read over sportsterpedia carb section.

[IXL2Relax]

Glad to see you got it repaired - JBWeld & Duct Tape will fix just about anything...

The SP CV40 page will give all the info to get the carb setup for the right Idle and Transfer operation. Just carefully follow the Idle Drop Method.

Sportsterpedia - Getting Ready to Tune Your CV40 Carb


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[wedge]

Good job. It looks nice and solid. If it ever cracks over time (and I think it will not), all you need to do is the same thing again.