Email Password Mobile Version / Desktop Version
Search
Results 1 to 17 of 17
  1. #1
    toxiceric
    Guest

    Default TECH: Fix Broken Fins

    I always hear people use the term "chipped" fins when they are selling a set of heads with busted off hunks of metal. Lets call it what it is...broken fins. I was putting one of my motors back together when I realized it has a couple broken fins. Somehow I don't remember these being like this when the bike was being ridden, but either way, they're broke now. Since I have to fix them, I figured I would post some pics of the process of fixing them. I'll keep adding a post to show the progress as I go.

    Here's the broken fins. The top one is completely gone and the lower one is missing a chunk.
    Attached Thumbnails Attached Thumbnails 100_6654.jpg   100_6655.jpg  
    Last edited by L7Josh; 02-22-2012 at 9:22 PM.

  2. #2
    toxiceric
    Guest

    Default

    Here's the start of the repair. Make a paper template of the broken fin and transfer it to the aluminum. I used a chunk of .125" aluminum scrap. The fins are technically closer to .150", but honestly, no one will know if you don't tell them.

    Another option to this, although a bit more complicated, would be to cast a piece. Since I have the ability to do casting, it was tempting. Honestly though, I'm lazy and it's not a perfect restoration, so I just don't feel like spending the extra time to do it. It would make a it a perfect fix though.
    Attached Thumbnails Attached Thumbnails 100_6658.jpg   100_6660.jpg  

  3. #3
    toxiceric
    Guest

    Default

    Now it's time to weld in the piece. I used a piece of .250" steel plate to space the fin from the top of the fin below it during welding. You need to chamfer the weld edge really good to get a good weld with as little seam at the bottom as possible. The beauty of welding HD castings is how wonderfully pourous and contaminated they are. It can take a few passes to get a good clean weld. I got pretty lucky on this one and got it with one pass using 4043 rod. I had already blasted these heads and put them in the oven for awhile to bake out as much of the oils and contaminants as possible. You can see the black crud that came out during welding. It wasn't bad enough to warrant grinding and re-welding, but sometimes it gets pretty annoying. Import bikes seem to have much better castings, and thus, less contamination. They are usually die cast as opposed to sand cast as well, which makes a big difference.
    Attached Thumbnails Attached Thumbnails 100_6664.jpg   100_6665.jpg  
    Last edited by toxiceric; 12-05-2011 at 1:41 PM.

  4. #4
    toxiceric
    Guest

    Default

    Now I carefully grind and shape the fin to match the rest of the head. It's looking pretty good, but it's still obvious that it has been repaired. After it's all shaped and finished, I throw it in the blaster to give it the cast look. Once it's done, it's virtually unnoticeable. I could have spent a few more minutes making it perfect, but again, this is going on my personal ride and the only one that will notice anything that's not perfect is me. All in all, pretty nice I think. Once it's on the motor and assembled, no one will be the wiser.

    So the lesson here is, it's not rocket science to repair fins. Just a little time, patience and a welder. Hopefully this will help someone that wanted to do it themselves but just weren't sure how to do it.

    If you don't have a welder and need this kind of work done, hit me up.
    Attached Thumbnails Attached Thumbnails 100_6668.jpg   100_6673.jpg  

  5. #5
    ARBY
    Guest

    Default

    Yeah man. All it takes it a little talent, a few tools and the determination to do something for yourself instead of buying your way through life. DIY is part of the motorcycling experience. Good job, nice write up!

  6. #6
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Nov 2009
    Posts
    663

    Default

    Very nice write up!

  7. #7
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Jan 2011
    Posts
    100

    Default

    Consider this my nomination for the greatest hits category.

  8. #8
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Aug 2009
    Posts
    233

    Default

    Excellent job and write up.

  9. #9
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2011
    Posts
    87

    Default

    very nice job man looks good

  10. #10
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2010
    Posts
    2,405

    Default

    Damn Eric, you make it look too easy. I wish the Army would give me more time off so I could come hang out and follow you around your shop and pester you with questions all day.

  11. #11
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Nov 2009
    Posts
    979

    Default

    great info !

  12. #12
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Aug 2009
    Posts
    131

    Default rod

    that 4043 is a nickle base rod right?? I need to do a repair on a ironhead with a crack in the rear motor mount boss on the rear head Thanks

  13. #13
    Junior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2011
    Posts
    27

    Default

    That's an impressive fix toxic! The bead is tiny man! What kind of welder are you using for that! is it an inverter?

    I have braised broken fins back onto an Ironhead before....but nothing like that. I'm gonna have to give it a try this weekend, thanks for the tip!

  14. #14
    toxiceric
    Guest

    Default

    I use an ancient Airco tig welder. 4043 is an aluminum rod, primarily for castings and softer aluminum. 5000 series rods tend to crack when used on castings, but work well with billet.

    Ironhead stuff would require a nickel rod, and a lot of preheating. How about someone more in the know on cast iron chimes in here? If I do a ironhead, I'll post up the process since it seems like a lot of guys here ride old sporties.

  15. #15
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Nov 2011
    Posts
    178

    Default

    Quote Originally Posted by toxiceric View Post
    I use an ancient Airco tig welder. 4043 is an aluminum rod, primarily for castings and softer aluminum. 5000 series rods tend to crack when used on castings, but work well with billet.

    Ironhead stuff would require a nickel rod, and a lot of preheating. How about someone more in the know on cast iron chimes in here? If I do a ironhead, I'll post up the process since it seems like a lot of guys here ride old sporties.
    Thanks for the info. The only trouble I have with this is that your fins broke off in an easy (er) spot, and you have tig. What alternatives are there to tig? I'm going to pick up a flux mig later. The fins that are broke off are in weird spots on both my bikes, mid cylinder and far back, the spacing is close too.

    I surfed around on the internet and saw a guy that pulled a shot kawasaki head, cut off a couple fins to fit, and JB welded them to the cylinder. Would that work? Would flux mig work?

    JB weld seems like a hick fix, maybe I'd be better off having the whole thing taken over to be tigged? I have to have some other tig work done (just sissy and bars) but don't want to haul the motor/frame down there. They bother me, two big breaks right out in front mid cylinder

  16. #16
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2011
    Posts
    77

    Default

    Nice work man.

  17. #17
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Nov 2011
    Posts
    178

    Default

    Quote Originally Posted by toxiceric View Post
    I use an ancient Airco tig welder. 4043 is an aluminum rod, primarily for castings and softer aluminum. 5000 series rods tend to crack when used on castings, but work well with billet.

    Ironhead stuff would require a nickel rod, and a lot of preheating. How about someone more in the know on cast iron chimes in here? If I do a ironhead, I'll post up the process since it seems like a lot of guys here ride old sporties.
    Post it up if you can, I'm going to practice on an old cylinder I can cannibalize later. First I'm going to bust off a fin, heat both up with my washtub forge, then try to weld it back on there. What still gets me is welding it back on in such a tight space. It would take a stinking genius to get those fins back on.
    There's got to be a way to do it though--heat it up to red hot and use the flux wire as a type of soldier? Tack them on the outside first after heating of course. We'll see.
    Anyone? Anyone? Bueller?

Share This



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
NEWS   FORUM   EVENTS   CLASSIFIEDS   BLOGDUMP   COMMUNITY   MEMBERS
CHOP CULT HOME

Advertise    |    Contact    |    2009ChopCult    |    Report Abuse    |    Conduct

Chopcult on Facebook