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  1. #1
    Moderator dirtdigger's Avatar
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    750 drag bike in progress

    I am going to do a build thread on the drag bikes I bought this fall. I have two stock frame drag bikes built in the 80's but basically it is the way they did it in the 70's. Stock frames with extended swing arms and struts and wheelie bars. Plan is to have them going by this spring and hopefully run them down the local 1/8. One bike had a 1000cc with many RC parts but it dropped a valve at some point. The other was a 1030cc with MTC aluminum rods and #4 rod broke and took the case and piston with it. Will post pictures etc as I have time and money to work on it.Click image for larger version. 

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  2. #2
    Moderator dirtdigger's Avatar
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ID:	4513 RC head is in good shape, just a valve seat touch up and some new springs and it will be good to go.

  3. #3
    Moderator dirtdigger's Avatar
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    Click image for larger version. 

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ID:	4513 RC head is in good shape, just a valve seat touch up and some new springs and it will be good to go.
    Click image for larger version. 

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ID:	4514F2 head before porting and machine work. A lot of work needed to get this head to work with the RC327 cam I am planning on using.

  4. #4
    Moderator dirtdigger's Avatar
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    Click image for larger version. 

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ID:	4515Click image for larger version. 

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ID:	4516 Should be able to find some parts in here for the motors lol

  5. #5
    CB750 Addict motogtp's Avatar
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    That is a lot of project for the winter DD. Hope you have fun.

  6. #6
    Moderator dirtdigger's Avatar
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    Yup, we have long winters up here, as long as the money keeps coming so I can buy parts it should all come together...I hope

  7. #7
    K2750tracy K2750tracy's Avatar
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    I really like the boxed swingarms on the race frames, have fun with these builds. I'll be watching
    old Honda junkie

  8. #8
    Holy crap. I'm envious.
    Everybody has a plan. Until they get a bee in their helmet.

    www.barndrunks.com

  9. #9
    Moderator dirtdigger's Avatar
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    Got a box of pistons! 72mm MTC 12.5 to 1 compression. Been cold as heck last week and haven't been working so I have been doing a lot of parts cleaning and parts mock up. F2 head I think is going to take a back seat right now. Going to take a lot of work and more money then I can spend right now so I am touching up the old RC head.
    Click image for larger version. 

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  10. #10
    CB750 New Member Dr Dante's Avatar
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    VERY cool! Any chance you would want to sell one of the frames and swingarms or know where there might be one for sale? I cant wait to see these done.
    Last edited by Dr Dante; 11-22-2014 at 09:10 PM.

  11. #11
    Moderator dirtdigger's Avatar
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    No, I plan on building both bikes.

  12. #12
    I need more updates here DD. NOW!
    Everybody has a plan. Until they get a bee in their helmet.

    www.barndrunks.com

  13. #13
    Moderator dirtdigger's Avatar
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    Not much new right now. Money is tight at the moment and I have some expensive parts I need to buy before I go much farther. Need to get some Carrillo rods before I can button up the bottom end. Holy crap they want some money for then. Still need to send the cylinder and pistons off for boring. About all I have done is mock up to start checking some clearances etc.

  14. #14
    Oh well. I'll just sit on my hands over here then, patiently waiting on update pics.
    Everybody has a plan. Until they get a bee in their helmet.

    www.barndrunks.com

  15. #15
    Moderator dirtdigger's Avatar
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    Bought me some xmas presents! Not sure when they will show up with the holidays though. Will soon be making some progress on a couple of motors RC head is done except for the finally milling once I get things together enough to figure the compression ration then I can determine how much I need taken off and the final MLS gasket finish. Want these motors to be around 12 to 12.5 to 1 more if I can get it but things will be getting tight at that point. Lots to do and lots of parts needed before spring...hope it all comes together. OK gotta go to work and make some money for some more parts!

  16. #16
    That Guy surffly's Avatar
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    Gunna run a mag?

  17. #17
    Moderator dirtdigger's Avatar
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    Nope, might run my RC distributor on one of the bikes. Not a big fan of mags as they take a good amount of power to turn...more power to turn then what they return in spark output. A good crank trigger setup has almost no parasitic lose compared to a mag or even the RC distributor. Not that I dont like the look mag setups there just not the go too setups anymore. For now running a dyna trigger going to a MSD box. This is the setup that was on the bike when I bought it...plus they run air shifters and a two step. In the future would like to run the optical Cycle X setup that is very adjustable but that all depends on how the racing goes etc. Got a lot of parts showing up this week so more pictures soon I hope!

  18. #18
    Moderator dirtdigger's Avatar
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    Click image for larger version. 

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ID:	4644 chrismas came a little late but the Carrillos finally showed up so now I can do some mock up and checking for bearings I need. This was the expensive part and an important part of the builds. Still need to have one crankshaft lightened and balanced and have a couple of blocks bored for the new pistons.

    Click image for larger version. 

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ID:	4645 Got this Smithy lathe for xmas so now I can turn and machine a bunch of the small pieces that will be needed for the bikes. Get more and more self sufficient when it comes to the machine work because I just cant seem to find a machine shop that I can trust and that is consistent with there quality.

  19. #19
    DAMN. I'm envious as hell right now. I'm also on the look out for a lathe and even a small mill. I, like you, can't find a good shop to help me out locally.
    So. Get those mock up picture comming!!

  20. #20
    Moderator dirtdigger's Avatar
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    Still doing prep work and mock up and waiting for cylinders and crank to get back from machining. Built a stand to mount the top cases to the mill so I could machine the top cases for the big sleeves. Click image for larger version. 

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ID:	4774Click image for larger version. 

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ID:	4775 I knew that mall/lathe would come in handy.

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