My 73 Yamaha TX750 Rebuild....

Discussion in 'Old's Cool' started by bulldog1980, Aug 28, 2008.

  1. SOS

    SOS Ignorance is a gift

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    I picked up a very ratty 1973 TX750 out of the junk yard last fall. Someone had given it a funky rat / cafe treatment sometime in the past and it had a cool rusty look to it so I stuck it in the window at the shop. Things slowed down over the last couple days so I put in on the lift to see what would happen. Cleaned the carbs, checked the timing and threw on an aux tank. Wiring was hacked so I put 12v straight to the coil. Scared the cramp out of me when it actually fired up and ran.:lol3

    I think it has the extended oil sump and I'll check for the hole at the points case (no evidence of oil though). I'm hoping to find the adjustable chain for the balancer. I really didn't expect it to run so now I'll look a bit more carefully. It should be a fun shop bike :evil
    #61
  2. ctune80

    ctune80 Been here awhile

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    I've always liked the TX750, and from what I hear the bike was great if you didn't live at the
    top of the rev range and kept up on routine maintenance. The balancer adjuster was
    also needed. A shame a little more development wasn't done before original release.

    I went to talk to the Yamaha Dealer in my old hometown recently, (I moved many years ago)
    We talked about the old days, reminisced about DT1's and XS's, when the talk
    turned to TX750's his facial expression said it all. That bike cost Yamaha and the
    local dealers a lot of money. I love the TX for it's uniqueness, but his experience
    was a lot different than mine!
    #62
  3. concours

    concours WFO for 41 years

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    Yup, no doubt the unhappy customers made headaches for the dealers, and the warranty work isn't lucrative either. This thing is faster, MUCH smoother, better brakes, better lighting, handles as well as my '77 Bonney.
    #63
  4. concours

    concours WFO for 41 years

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    I see the balancer chain retrofits on ebay once in a while. Be very carefull, there is a bunch of small parts (spacers, etc.) you really NEED to do this retrofit. The ancient parts retrofit list calls them all out.

    http://www.tobyfolwick.com/tx750/textual/pbadj_1.php

    http://www.tobyfolwick.com/tx750/bulletin.php
    #64
  5. lsettle

    lsettle Adventurer

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    Nice work on the TX.

    Question for you. When you check the oil level, is the dip stick inserted all the way down or should it be sitting on the tube?


    Thanks,


    Lawrence
    #65
  6. concours

    concours WFO for 41 years

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    Thanks! Seated all the way down is the correct method.
    #66
  7. concours

    concours WFO for 41 years

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    The spin on oil filter I fabbed up:

    [​IMG]

    [​IMG]

    [​IMG]
    #67
  8. far2389

    far2389 Adventurer

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    I just had a batch of aluminum oil filter adapters made for my 4 Tx's. These are the ones that replace the expensive stock filter and use the BMW R65 filter - work great. Have some extra's to sell if anyone interested. Comes with new filters and oring (the other parts are used from the old filter). PM if interested I can email pics.
    #68
  9. lsettle

    lsettle Adventurer

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    I am on the fence to install the BMW filter or the spin on type, I have the spin on set up already.

    I did change the oil today, 15w-40 Rotella is what I used. I have the 74 with the oil cooler. Thanks for answering my question about the oil dip stick!

    I bought this bike back in May when I was across the world off the coast of Libya, (Canadian Navy). My father went and pick her up for me, a bit of a gamble considering that she was not running at the time, since then I fixed the issues and ridden about 100 miles. She rides nice, she does like around 3000 rpm onward.


    Lawrence
    #69
  10. lsettle

    lsettle Adventurer

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    I forgot to include the you tube video of her running for the first time in about 10 years.

    http://www.youtube.com/watch?v=0NkTtHC6ZCI

    Another question; the tubes going to the oil filter, which tube do I use for the input to the spin on filter and the output? Thanks for the pictures of your setup, Concours!


    Lawrence
    #70
  11. concours

    concours WFO for 41 years

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    I forgot now... I have them marked with sharpie. A half stroke of the kick starter showed right away the oil "out" line.
    #71
  12. concours

    concours WFO for 41 years

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    She should pull cleanly down to idle, final drive tension is key, your adjustable balancer shaft chain must be set right. That involves removing the oil sump and extension and measureing backlash with an indicator on the tip of the counterweight, then loosening the locknot and adjusting the eccentric shaft JUST A BIT. Carbs are OK? Idle circuit clean and functional?
    #72
  13. SOS

    SOS Ignorance is a gift

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    I've been looking for the adjustment on the balancer. Thanks! :D I've been through Toby's site and there is a ton of good info there, but I couldn't find any actual adjustment procedure. The on-line fische show the differences, but I haven't taken mine apart to see it in person.

    I went through the rest of the motor adjustments and made a simple wiring harness to start it up without frying anything. It started and ran well yesterday. Got a quick adjustment done on the carbs and it idled fine, had good response and seemed smooth. The motor is smoking a bit, but it hasn't run in who knows how long and I did add a fair amount of oil in the cyclinders for the compression test. Also, I do not know if these bikes are prone to wet-sumping like the old brit bikes.

    I've got the extended oil sump so hopefully I've also got the balancer mod:norton
    #73
  14. concours

    concours WFO for 41 years

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    The retrofits were entirely peicemeal, so sump extension does not mean adjustable chain. The factory and dealers were all over the map with this stuff. Easy to check, look in under your shifter.. BIG hex plug? Or big jam nut woth the shaft having a slot milled in it, and a tab washer to lock the nut? Here are the links to the adjustment procedure:
    http://www.tobyfolwick.com/tx750/textual/pbadj_8.php
    http://www.tobyfolwick.com/tx750/textual/pbadj_9.php
    As for wet sumping, I've never experienced it, and never read anything about it for a TX. One of the Brit "quirks" they solved with some sound engineering.
    #74
  15. SOS

    SOS Ignorance is a gift

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    Thanks a ton! I don't know how I missed it on Toby's site, but I appreciate your help. I just started my own thread so I don't distract from this one.

    Thanks Again!
    #75
  16. lsettle

    lsettle Adventurer

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    Concours- Thanks for the replies, yes, the carbs are clean and the idle circuit is functional. Also, I did not know what to look for to see if I had the balancer adjuster fitted to my bike. Looks like it do ;-)

    Thanks to SOS for asking that question as I did not know....

    I have uploaded a picture of the adjuster and a picture of the bike.

    Here is one of the 1974 TX750 - http://img840.imageshack.us/img840/1995/picture001vq.jpg

    and another of the adjuster for SOS - http://img200.imageshack.us/img200/2420/picture004hy.jpg
    #76
  17. concours

    concours WFO for 41 years

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    Any progress?
    #77
  18. farmrjohn

    farmrjohn Been here awhile

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    Just joined after acquiring a '74 TX750 and already have a few of questions. 1. I've heard that synthetic oil is a problem with the clutches by being too slippery. Is that true for ones that are motorcycle specific oils and/or ones that aren't "economy" rated, ie. Shell Rotella T-6, Mobile 1 Diesel etc.? 2. Are there any diagrams for the spin on oil filter modification? That looks like it would work without removing the chain, unlike the BMW element option. 3. Does anyone have a source for an owners manual?
    #78
  19. vernon dent

    vernon dent Been here awhile

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    [​IMG]
    #79
  20. CalsXS2

    CalsXS2 Been here awhile

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    Do you have any filter's available. Thanks.
    #80