Carb thanks Carl L.

Wed Apr 06, 2005 1:52 pm

:shock: Just pulled apart the carb and couldn't belive how much the top piece was bent from over tightning. It is worse than the carb in your first picture. I looked at it and saw that it was beyond filing and was scraching my head trying to figure out a way to straiten it out without breaking it.

8) I had seen your article before and just reread it and will give it a try.

For larger pieces that do not have anything sticking down like the carb bowl. Rather than use a file I use a old mirror put a sheet of sandpaper on it and sand aginst that. So it gets the whole thing at once and I don't have the side of a file diging in where I do not want it to.

Thanks Billy :{_}:

Wed Apr 06, 2005 4:02 pm

Billy,

Run the edge of the file over the grinder to dull the teeth so it can't cut. A little dab 'll do ya.

Wed Apr 06, 2005 4:19 pm

I don't have many sharp files so that's not an issue with me!

You'll find the bowl casting won't be much out of whack. The throttle body casting is a whole other story! At last year's Cubfest in New Brunswick, we used a adjustable wrench, a soft-jawed vice and brute strength to true up Rudi's carburetor. Couldn't get any grip with the C-clamp and washers whilebolting the halves together so we worked directly on the throttle body.

Don't try to bend one spot too much, work your way around the throttle body, then place it on the bowl and see where it needs more straightening.

Wed Apr 06, 2005 5:57 pm

I'm puttin 2&2 together here. I've noticed recently that the IH carb apparently has as weekness for the upper casting warping. And I'm guessing thats why mine and some other Cubs have a Zenith replacement on them. At some time in the past my Cub probably had a carb that was rebuilt improperly resulting in warped casting and the previous owner just bought the Zenith replacement. I have since purchased a manifold to match the Zenith with the larger flange.

Wed Apr 06, 2005 6:25 pm

Billy:

Carl wrote:

You'll find the bowl casting won't be much out of whack. The throttle body casting is a whole other story! At last year's Cubfest in New Brunswick, we used a adjustable wrench, a soft-jawed vice and brute strength to true up Rudi's carburetor. Couldn't get any grip with the C-clamp and washers whilebolting the halves together so we worked directly on the throttle body.

Don't try to bend one spot too much, work your way around the throttle body, then place it on the bowl and see where it needs more straightening.


After watching Carl work his magic last summer (and yes :!: I had images of a shattered carb every time we tried to straighten that carb. I thought I was going to have a conniption fit :roll: :!: :oops: :roll: ), and after playing with a few more carbs since that time, I have come to the conclusion that most carbs which have warping issues can indeed be trued given time and sufficient patience.

The process that you describe - lapping - is probably the safest method of truing up a carb that does not have serious warpage. For one that does - often times drastic measure may be called for such as in the case of Ellie's old carb. Either way, once the carb bodies are close - a good dull file or a lapping board(read plate of glass etc.) is the best way to mate the two surfaces.

I am amazed by what I have learned in the past couple of years since owning Ellie. I am thankful for informative articles by knowledgeable people such as Carl, George and others who have generously gave of their time and talents to share these gems of knowledge with us. :!: :D

Wed Apr 06, 2005 6:41 pm

Here, here!

Had it not been for Carl's excellent work and Rudi's awesome job of making that effort available to the masses I would have put it back together (aka 'rebuilt' it) and possibly never known the difference.

So, my hat is once again off to Carl and Rudi for helping us all out!

Now I find out that my manifold is off a numbered Cub formerly with a Zenith Carb... I knew the exhaust was different, but never knew that the intake was too, till someone (George W) pointed it out:
http://i2.photobucket.com/albums/y40/Bu ... c4c64a.jpg

I would be willing to trade it for one that is right, but I think I have gone too far hacking it together (exhaust is larger ID, so it required a bushing)
http://i2.photobucket.com/albums/y40/Bu ... 7935ee.jpg


THANKS GUYS!

Wed Apr 06, 2005 7:20 pm

You may not be interested but Tom at TM has just gotten in two replacement Manifoldsto check out a new supplier. They are awsome. nicely milled ports and carb flange, not paper thin, just the way they should be. I saw them the other day.

Bill

Wed Apr 06, 2005 7:34 pm

The bottom half is what can be lapped on a plate, but rarely needs it. The top half where the warpage is can't readily be lapped because of the projecting venturi (non-removable) and the supports for the float. We did an overhaul at CubFest 2003 including straightening the top half. I agree that it is difficult to get exactly the right force in the right places. I prefer to use 5 identical washers. 4 to use under the screws as spacers and the 5th one to use as a gauge. If you chicken out before you get it straight enough, take it somewhere there is a milling machine. This is how I did my first one to get it "dead nuts on".

Image

Wed Apr 06, 2005 8:24 pm

Hey Buzzard, I got a manifold that is real nice that didn't sell on Ebay.

Wed Apr 06, 2005 8:56 pm

:{_}: Thanks everyone

Wow I got it pretty close the gasket will take up the rest. The worst part to fix was next to the fuel inlet. I had it in the vice nuts between between the halves. I used a drift and lightly hammered it (tapped?) And I think the pressure from the vice and the vibration from the hammer moved it back in. You may not belive this but I wasn't even going to touch the idle tube but it unscrewed by hand :!:

When I put it back together the halves went easy till the last 1/8" then I had to push it firmly to go the rest of the way together like the bottom choked down for a tight fit :?: Is this normal :?:

:{_}: :{_}: To all of you (us) who are unsure ask FIRST I have almost always had an answer or been pointed it the right directon within an hour. If you are in a hurry do a search I know I saw Carl's web page but could not rember where I did a search went through 3 pages found it on Rudi's website under Maintenance Tips and Techniques http://www.cleancomputes.com/Cub/Mainte ... index.html. I ask even when I think I know what I'm doing and can't belive how often someone has a better or easyer way of doing somthing. And I grew up in the auto parts / automotive machineing world. Ask it will save you bigtime. :P

Billy

Thu Apr 07, 2005 10:38 pm

Yep! You are right Billy. This is an amazingly good bunch of guys. I also was suprised that I would post a question and go back to the garage for a bit and the answer was there when I looked at the board.

Thanks for the offer of the manifold WK, but I am pretty sure I will get by fine with it the way it is. I don't think the size of the ears on the intake matter as the carb bolted right up.

One day I will replace the pipe and then I may look into the correct manifold.