1974 Honda MT125 Elsinore VMX Racer Refresh.

Discussion in '2 smokers' started by RustyStuff, Sep 14, 2015.

  1. RustyStuff

    RustyStuff Long timer Supporter

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    I'll have to order some of that castor oil for this bike. I've stayed away from it with my Power valve 2t engines because I don't want to gum the PV up. Ordered a set of jets so I can tune it, I figure I'll start 1 size above the honda manual spec just to be safe and I ordered another weisco piston today so I should be able to test run it next week. What's the best way to break in a fresh iron bore 2t engine? Ride it around my yard slow for a while?

    Send me a few pic's of the seat and let me know what the shipping will cost, does it mount like the CR seat with bolts or does it flip up and have a key lock like the MT seats?
    #41
  2. juicy flawless

    juicy flawless Toxic Raccoon

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    #42
  3. kenny robert

    kenny robert Long timer

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    #43
  4. RustyStuff

    RustyStuff Long timer Supporter

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    Pictures didn't show up?
    #44
  5. kenny robert

    kenny robert Long timer

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    warm it gentlly but quickly rip up through the greas a few times don't get it real hot
    then some say on an aircooled motor to pull the barrel and sand off the piston high spots
    thats what kawi said to do on my brand new 86 200
    ah i wasnt sayin oil just the power additive it has bean stink too use it in your 4 t 's as well

    \,
    #45
  6. kenny robert

    kenny robert Long timer

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    IMG_3934.JPG IMG_3938.JPG IMG_3939.JPG IMG_3931.JPG IMG_3934.JPG IMG_3938.JPG
    #46
  7. RustyStuff

    RustyStuff Long timer Supporter

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    Thanks for the Seat Kenny it's great.

    It also about the best part of this damn weekend. I did a marathon wrenching session last night. Got the engine buttoned up with the New cylinder, Wiseco piston, new gaskets and I finished up the CDI wireing.

    No go. The spark is a bit weak but the biggest problem is the damn crank seal blew out and got messed up on the rotor. Now another week of waiting for more parts....
    #47
  8. kenny robert

    kenny robert Long timer

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    yer welcome sucks about the no start seal blo
    i just rememberd that saddle went for a stint on my bsa for a while till i changed ed it up to a solo sprung seat
    hope you dont mind a bit of photo whore--ing bsa and a carb kawi 014.JPG ng
    #48
  9. RustyStuff

    RustyStuff Long timer Supporter

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    Nice Beezer, 350 or 500?
    #49
  10. kenny robert

    kenny robert Long timer

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    thanx m8
    500seesea:-) xb33
    #50
  11. RustyStuff

    RustyStuff Long timer Supporter

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    Today's discovery, the cause of the seal blowout was the CDI ignition plate. There isn't any sort of seal retention on the block, stock the MT125 uses it's points plate to hold the seal in. The CR plate doesn't do that. Looked at the parts diagram on Bikebandit, doesn't appear to be a keeper or c-clip on the cr125 engine, so I'm not sure what's going on there to stop it.

    and I'm tired of attempting to start this bastard tonight. I've got plenty of compression, a fat spark with the points ignition stuffed back on for testing, and I've got fuel, size 60 pilot and size 125 main as per the manual. Plug wet with fuel after a few pushes up the driveway and no go.
    #51
  12. OSR

    OSR Adventurer

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    Might be out of time, double check your ignition since you were fooling with it earlier.
    #52
  13. bbrock

    bbrock n00b

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    #53
  14. bbrock

    bbrock n00b

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    First time user here and looks like I’m not so sharp on replies. Here we go again
    I bought a 74 MT125 basket case without a carb and trying to decide on the CR 125 route or just an MT125 carb from eBay. How hard was your conversation and was the effort worth it.
    Not sure I really want to fab up all the insulators and airbox stuff
    Thanks
    #54
  15. RustyStuff

    RustyStuff Long timer Supporter

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    It would appear that the conversion is not as easy as the proponents have made it sound, in my experience.
    I have never gotten it to run. I did discover that honda might have made the rotor keyway on the MT crank 180* out from the CR to discourage this swap, the only way to get it to spark at the proper place is to flip the CR125 stator 180*. I would appear that the MT head needs to be swapped with a CR head as even with a fresh bore and weisco piston I can't get more than 120-125psi compression with a CR jug and piston and MT head. The CR CDI's seems to not exactly be reliable as they have aged too.
    Idk, if I was at the beginning of the project i wouldn't bother. Way too much money and time into it and it's never really worked. You might have better luck with it, Idk. The ignitions can be a problem. The factory CDI I bought was a dud, the only new replacement is like $500. I managed to homebrew a 12v battery powered total loss system useing a HEI moduel from a chevy triggered by the CDI trigger coil and a HEI ignition coil that seems to work but it's timing locked and again, even with that I still don't have the compression to make it run beyond pops apparently.
    #55
  16. bbrock

    bbrock n00b

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    Oh boy. Thanks for your candour . That all sounds beyond my capabilities. You saved me - Thanks again
    #56
  17. RustyStuff

    RustyStuff Long timer Supporter

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    I'm glad I could help.

    Way too much time invested with only frustration to gain.
    #57