Carb flange

ChuckZZ

Member
Does anybody have a proven method of repairing the carb flange where it bolts to the motor? As is common, especially on plate motors, I have a carb where the right hand side is deformed potentially causing a vacuum leak.
 
Pretty sure you have too pull it into place . On a surface type plate or jig .
No doubt trickey .
Quick rap rap with a leather faced hammer .
 
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File it flat. Edit: didn't know that could DQ you. New info Don't file it.
 
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Well you can have a machine shop make you a 1/2” thick steel block with the appropriate holes in it. Place washers on your bolts or better yet studs and tighten evenly with slight heat till it sits on its new solid foundation, then don’t use a breaker bar to put it back on the tank.. 😂
 
You are not allowed to file (or machine) the gasket surface on the flange, nor are you allowed to double the gaskets on one side of the restrictor plate. Both are illegal.
The methods used above are what we try to do to save them here -- and occasionally they break. If it's not leaking now, keep running it (with a fresh gasket each time it has been removed.) Just stop over-tightening it.
If you're concerned about the bolts coming loose, drill them and use safety wire, or a little stripe of paint from the head of the bolt to the carb (akin to tech paint.)

-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Well you can have a machine shop make you a 1/2” thick steel block with the appropriate holes in it. Place washers on your bolts or better yet studs and tighten evenly with slight heat till it sits on its new solid foundation, then don’t use a breaker bar to put it back on the tank.. 😂
I made a fixture to do this. I more or less anneal the aluminum flange. I take a felt marker..aka "Magic Marker" and color the whole flange area, kind of like layout dye. Using a low flame on my torch, I heat the flange area until the marker disappears. then straighten the flange, slowly. Then I touch up the flange on a surface place with some 320 grit paper with WD40. BE PATIENT!!
 
I made a fixture to do this. I more or less anneal the aluminum flange. I take a felt marker..aka "Magic Marker" and color the whole flange area, kind of like layout dye. Using a low flame on my torch, I heat the flange area until the marker disappears. then straighten the flange, slowly. Then I touch up the flange on a surface place with some 320 grit paper with WD40. BE PATIENT!!
Sounded great until you mentioned touching up the flange with sandpaper. That'll be a DQ in the tech barn almost guaranteed. This is a gasket surface that cannot be machined, scraped on, filed on, sanded, polished, etc. It must remain "from factory."
The reason for this, is that we used to angle mill the flange to promote better airflow (back in the '80s probably) until it was declared a visual tech item. Even very light sanding was being done to remove/disguise machining marks, so the powers that be back then made it a rule that this gasket surface was a "do not touch" visual tech.
 
I made a fixture to do this. I more or less anneal the aluminum flange. I take a felt marker..aka "Magic Marker" and color the whole flange area, kind of like layout dye. Using a low flame on my torch, I heat the flange area until the marker disappears. then straighten the flange, slowly. Then I touch up the flange on a surface place with some 320 grit paper with WD40. BE PATIENT!!
This sounds almost like shrinking .
I have found shrinking metal to be quite effective as a straightener .
Much more effective then bending for many situations .
 
Sounded great until you mentioned touching up the flange with sandpaper. That'll be a DQ in the tech barn almost guaranteed. This is a gasket surface that cannot be machined, scraped on, filed on, sanded, polished, etc. It must remain "from factory."
The reason for this, is that we used to angle mill the flange to promote better airflow (back in the '80s probably) until it was declared a visual tech item. Even very light sanding was being done to remove/disguise machining marks, so the powers that be back then made it a rule that this gasket surface was a "do not touch" visual tech.
I know Brian, I was doing this back in the 80's, and to me a visual tech is an opinion and you know what they say about opinions.....everyones got one. I'm not junking a $400. carb over some ones opinion. Being a machinist I know all about surface finish. I ran these carbs in WKA Nationals and been thru tech with them with no problem. I didn't do this for a performance gain, I did it to save a carb.
 
I know Brian, I was doing this back in the 80's, and to me a visual tech is an opinion and you know what they say about opinions.....everyones got one. I'm not junking a $400. carb over some ones opinion. Being a machinist I know all about surface finish. I ran these carbs in WKA Nationals and been thru tech with them with no problem. I didn't do this for a performance gain, I did it to save a carb.
I understand that...so was I. I'm just saying that it is not legal to sand that gasket surface. Not surprised that it slipped through tech. There are many things that do.
I understand trying to save a good carb. And I understand that your motivation was not for performance gain...but there are folks who work this area/angle, then disguise their work by manipulating/sanding/acid/etc. the gasket surface so that you can't see machining marks. This is why the visual was placed in the rules. I'm also not a fan of interpretive rules like "visual finish" and "compare to known stock part." I much prefer solid measurements for tech.
$400 carb? Maybe I need to raise my prices, lol. I just sold a new national level flathead carb for $300.
I have a few more if you need. :)
 
Done it for yrs,,been teched 100 times and never been dq'ed
Rules are rules and i will stick by them. Thats why we always have either A a backup motor on hand or B a backup carb in the track box. Because when we win we dont want our little ones disappointed when tech dqs them.
 
Stick thin wire against the gasket seating face in a few places preferably on the bottom or on the exhaust side of carb before you snug everything up and leave it sit till race day then pull them out. It stinks trying to get one of those vacujet style carbs to idle and even worse idle down with a vacuum leak but it did get you more air into the cylinder.. more dirty dusty ring and valve guide destroying air.. 😂 not that I’ve ever tried that just heard this worked… 🤐
 
Dumb question but if it's a plate motor wouldn't any carb work just as good as another?
Thats what I was thinking for a plate motor, I would think that about any carb from any motor builder would work on it. The restrictor plate is messing with the flow so much I wouldnt think it would be a big deal about what carb you are using.
 
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