1976 YAMAHA RD400 Custom

Discussion in 'Some Assembly Required' started by Fast Idle, Feb 9, 2019.

  1. villageidiot

    villageidiot Long timer Supporter

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    Looks like a crank can be had for 90-300$ depending on year.

    Gotta love a 2 stroke.

    Wonder if there’s a big bore kit.
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  2. Fast Idle

    Fast Idle Since the Sixties Supporter

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    Yeah I looked on ebay and was happy to see all the rebuild kits. :clap
    After running the numbers it turns out the bike is a 93 and should be able to use a 92-2000 crankshaft but all the kits I see are for newer models.:baldy
    Don't see any used cranks on ebay right now either. The cylinder is trashed as well.
    I'll have to keep an eye out and maybe something will turn up. Wouldn't want to put more money in it than it's worth.
    Too bad there's no crank and cylinder kits, that would have been the way to go.
    Don't know much about the RM's and I'm wondering if a later model motor will bolt in? Need to get schooled up I guess.
  3. Fast Idle

    Fast Idle Since the Sixties Supporter

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    I see cranks and rods out there by Hot Rods. Anyone have experience with them?
  4. villageidiot

    villageidiot Long timer Supporter

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  5. villageidiot

    villageidiot Long timer Supporter

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    93 is 2 stroke heyday.

    gotta do it all period correct MX, the early 90s were AWESOME on the eyes.

    [​IMG]
  6. Fast Idle

    Fast Idle Since the Sixties Supporter

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    Cool, thanks VI.
    Guess I'll need to start a new thread.:photog
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  7. villageidiot

    villageidiot Long timer Supporter

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    those parts are for a 99, but should be the same.

    there are a couple used cranks on eBay, but you already have one of those haha.
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  8. villageidiot

    villageidiot Long timer Supporter

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    93 is legal for AHRMA next gen MX, so there ya go
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  9. everready

    everready Stuck in Ohio....Ugh!!!

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    Sparkingdogg might have the parts you need.
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  10. Kai Ju

    Kai Ju Long timer Supporter

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    I actually liked the idea of a four stroke engine swap...
    Just don't know whether the engine room is big enough to accommodate a four stroke.
  11. villageidiot

    villageidiot Long timer Supporter

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    i think it'd be great, but the frame is already powder coated which doesn't lend well to mods.
  12. fast1075

    fast1075 Not a Lemming Supporter

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    I had a RM125. It hauled my then 119 pound ass around pretty good. Pin it and dance on the shifter. Lots of fun.

    You need to find and restore a Gen 1 Honda CR500. Evil, wicked, mean. Would roost fist sized rocks in any gear. PANG, PANG, PANG, ROOOOOSTTTTTTT! Terrifying. I would want one if I could still kick it without fear of breaking something.
  13. MotoChris521

    MotoChris521 expert apprentice

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    1993 RM125
    hqdefault.jpg
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  14. Fast Idle

    Fast Idle Since the Sixties Supporter

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    I have to keep telling myself NO, NO, NO on a CR500. :lol3
    My old hill climber buddy Steve use to out run street bikes with a CR500. And he was in the ditch while they were on the pavement. :photog
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  15. Fast Idle

    Fast Idle Since the Sixties Supporter

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    I think it will be fix what needs fixing and then ride it for this RM125.
    Ordered a crank today and stripped the cylinder so it can go out for plating.

    The new shocks for the RD showed up.
    P1120020.JPG
    They ride petty darn good. Way, way better than the other set.
    P1120024.JPG
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  16. villageidiot

    villageidiot Long timer Supporter

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    I think fix it and turn it into a budget ditch banger. You know, like your Kawasaki that looks too nice
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  17. Franque

    Franque Been here awhile

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    Sometimes those cranks can be rebuilt, like the crankpin can be pressed out and replaced along with the rod and bearings. As long as the main bearing races are good, and the crankpin is replaceable, that's what I would do, and those parts might be available from Suzuki. I used to hear mixed reviews about Hot Rods from some guys who used to race and owned a Honda dealership, but I don't have first-hand experience.
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  18. jays100

    jays100 Been here awhile

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    My experience with Hot Rods is ok. They like the high end of the side clearance and run a bit more oil in the mix. Anyway, a workable philosophy on two strokes is to run as much oil as the plug(s) will fire, is best.
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  19. jays100

    jays100 Been here awhile

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    Or......
    And for something completely different, why don’t you try to shoehorn a GS400/425/450 motor in there? Could be a head scratcher and with your skills, very doable!
  20. DiggerD

    DiggerD DougFir from SuperDuke Days

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    I think fix it and turn it.

    Lov my KaToom 300 2 smoker...lot's of bottom end.
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