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Project 1973-4 Yamaha AG100 Racer

Discussion in 'Other Projects - Other Bikes (non 250's)' started by Mike Fulcher, Feb 10, 2018.

  1. Mike Fulcher

    Mike Fulcher Active Member

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    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    Hello everyone, just a few pics of a project I have been working on for the last twelve months or so.
    It is based on a 1973-4 Yamaha AG100 & has been modified for use in Bucket & pre 73 classic racing.
    The engine uses the crank case, gearbox & clutch from the earliest version, allowing the bike to race in pre 73 events.
    The cyl. barrel comes from the later engine which has a much larger intake port & reed valve block.
    The piston also is a later version with narrow piston rings which will allow a higher RPM limit.
    The cylinder head has been highly modified to allow as high a compression ratio as possible & surfaces have been machined radially to help stop detonation.
    I have used dual stage Boyson reeds & a larger AG175 carb.
    The expansion chamber has been designed to give peak performance at around 8000-9000RPM
    Exhaust port has been widened & opened out to approx 210 degrees.
    Standard points ignition has been retained using a later model lighter flywheel.
    I chose an AG100 frame that incorporates a twin tube design, looks more period.
    Front forks are from the larger AG175, font brake is a twin leading setup from a YSD2.
    New alloy rims of 18" are laced to the brake drums with new 4mm spokes.
    Clip on bars, period style fuel tank, cafe racer style seat, home made rear set foot pegs, half front fairing & a Yamaha paint scheme to finish it off.
     
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    Last edited: May 5, 2018
  2. Mike Fulcher

    Mike Fulcher Active Member

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    My Bike:
    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    P1080134.JPG P1080135.JPG P1080281.JPG P1080282.JPG P1080283.JPG P1080284.JPG P1080285.JPG P1080297.JPG P1080298.JPG P1080299.JPG P1080300.JPG P1080346.JPG P1080347.JPG P1080348.JPG P1080349.JPG P1080367.JPG P1080368.JPG P1080369.JPG P1080370.JPG P1080371.JPG P1080372.JPG P1080373.JPG P1080374.JPG P1080375.JPG P1080376.JPG P1080378.JPG
     

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  3. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    Welcome to the forum
    That's a sweet looking bucket racer !
    That vented TLS front hub/brake look's good too.
     
  4. Mike Fulcher

    Mike Fulcher Active Member

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    My Bike:
    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    My next project is this 1985 Yamaha SRX250 Rego on hold, I want to complete the Cafe Racer look, follow the progress.


    P1080407.JPG P1080408.JPG P1080409.JPG P1080410.JPG
     
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  5. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    My Bike:
    1937 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, FT500 plus a few others.
    What a lovely little bike. :thumb_ups:
     
  6. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    Murdo means the AG100.. :) He isnt a big fan of Cafe Racers :)
    Both are lovely bikes.. nice to see another little SRX250 in here... not that I am a big fan of the Black on Black but gloss Black does go well on those tanks :)
    :welcome:
     
  7. Mike Fulcher

    Mike Fulcher Active Member

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    Thanks for the comments, this is how I received the bike, there will be a lot of changes, I will be highlighting the black colour scheme, the paint is in pretty good condition so no real need to change.
    It already has clip on's, (not set up right) the rear sets are standard & give a good comfy riding position.
    I will be fitting a proper cafe racer style seat & front mini fairing, all in black of course.
    I hate the exhaust, this will be changed to get rid of the horribly restrictive collector box under the engine to a 2 into one collector & a nice tapered megaphone.
     
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  8. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    Mike has done an excellent job with the AG100. This is mine and what it would have started out as.
    CJ250 011.jpg
     
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  9. Mike Fulcher

    Mike Fulcher Active Member

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    My Bike:
    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    Thanks for the comments, look I'm an old codger, I'm finding it very hard to navigate this site, How the hang do you start a questions & answer forum?
     
  10. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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  11. Mike Fulcher

    Mike Fulcher Active Member

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    I'm still having a lot trouble using this site, I'll try & download some progress pics on the Yamaha SRX 250. the following pics are of the Chinese "V" twins I was asking about previously. Does any one Know if they are still being manufactured?

    HTB1NxvsGFXXXXabXFXXq6xXFXXXF.jpg HTB1r4HsGFXXXXXtXFXXq6xXFXXXT.jpg oV4GJSV8D6185.jpg P1080424.JPG P1080426.JPG Yamaha SRX 250
     
  12. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    Same engine is used in the latest model 2018 Hyosung 250's


    hyo-gt250_01_small.jpg
     
  13. Mike Fulcher

    Mike Fulcher Active Member

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    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    Just a few more pics of my progress with the SRX250
    P1080436.JPG P1080435.JPG P1080437.JPG
     
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    Last edited by a moderator: Apr 7, 2018
  14. Mike Fulcher

    Mike Fulcher Active Member

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    My Bike:
    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    & a few more, just added some side panels made from marine 3 ply. P1080439.JPG
     

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  15. AGman

    AGman Active Member

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    Can I ask what seat and fuel tank you put on the AG (and where they were sourced from) and if you had to make a lot of changes to the frame for them to fit?
     
  16. Mike Fulcher

    Mike Fulcher Active Member

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    My Bike:
    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    Purchased from www.aliexpress.com. no frame changes at all, just used Aluminium adapter plates, home made.
    Just a word of warning, when buying from these guys make sure you buy with the freight free option,
    otherwise the shipping costs added on can be horrendous.
     
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    Last edited: May 11, 2018
  17. Mike Fulcher

    Mike Fulcher Active Member

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    My Bike:
    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    Final pics of completed Yamaha SRX 250, not a full restore, just completed the cafe racer to my liking's & made sure every thing working as it should.
    Just waiting for a new set of fork seals & I can go back for the WOF Recheck & then its up for grabs.
     

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    Last edited: May 25, 2018
  18. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    I like that megaphone on the SRX Mike.. care to share where you got it etc.. should sound nice too... hopefully.
     
  19. Mike Fulcher

    Mike Fulcher Active Member

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    Yep it sounds beaut. available from www.aliexpress.com & only about $60-70 NZ to the door.
    But once again don't get burnt by the freight charge ripoffs, take the freight free option every time.
     
  20. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    Do you have a link to the actual store you bought it from?
     

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