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T 140 shift plunger/quadrant spring

Discussion in 'Triumph (Classic)' started by xbacksideslider, Jun 23, 2019.

  1. xbacksideslider

    xbacksideslider VIP MEMBER

    Joined:
    Aug 19, 2010
    Bike fails to shift into 3rd. Not always but too often. Seem like it is not a problem with dogs but with cam plate and plunger. Replaced plunger spring with a stronger one from hardware store and that helped but not enough

    Before that I Ordered a spring from a proper source and the one I got was both shorter and weaker than the one I had.

    Previous owner had added a second copper washer to plunger to reduce tension. When I removed it and installed a stiffer spring, shifting seemed to improve

    No problems downshifting into 3rd or staying in 3rd gear once I find it
     
  2. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    This is an area where some ‘selective assembly’ helps with Triumphs.

    I had to fiddle with different plungers and different springs and different spacing on mine to get it nice.

    In my experience, Triumph boxes are also quite sensitive to gear oil choice. Molyslip gear additive always seems to help in Triumph boxes for me.

    But... your issue sounds to me like it could be related to the gear change quadrant and / or gear change quadrant plungers.

    The 4 speed quadrant and plungers are slightly different to the 5 speed. They do fit, but do not function correctly.

    It’s quite possible someone inadvertently fitted the wrong parts. And / or they could be nasty pattern parts. And / or they could be too worn.

    Some good info as to what to look for here:

    http://vintagebikemagazine.com/tech...ating-of-a-4-speed-to-a-5-speed-transmission/
     
    xbacksideslider likes this.
  3. xbacksideslider

    xbacksideslider VIP MEMBER

    Joined:
    Aug 19, 2010
    Thanks. I take it that the likelihood is that the camplate and shift forks are deformed or worn but that the plunger/spring and the quadrant/plungers are expedient/optimistic points on the diagnostic checklist
     
  4. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Yes, much easier to check the quadrant and plungers as they’re in the out cover.
     
  5. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    Ceturies ago , after having endured a lifetime of throwing out of gear , usually second , at maximum tourque ,-
    How it never blew apart is unknown .- and the odd marvelous grauch clunk using the heal to reingage , -
    still holding a Z-1 after the second ' occurance ' ,
    Some Time later ' we ' removed the index plunger , and thought squeezing it that the spring was a bit soft . Quite So ,
    A good tug had it two or three times its existing length.
    So a good sqish got it back 1 1/2 or more , Still fittable with a bit of dexterity .

    The comparison in shift was it was then a good deal stiffer , bot the ' indexing ' was decidedly more pronounced .
    And the ENGAGEMENT was definative . Descernable with the toes .

    So to get all worried when shuch primative efforts produce decided rewards , would be missleading in many ways .

    Id think initially , a ' Good ' tension would be a bit indeciseive stationary , but decidedly observable rolling .

    Scnick Clunk like .

    If youve got the cam plate out , doing the Mert Lawill massage with the eyes , a finger tip , and deburring with a stone if required ,
    then polishing the track . Or Tracks ( for the selector rollers ) seeing that theres no binding or rough spots . Nor excessive clearance .

    Remembering that the 500 cam plates had dual reinforcing straps welded acoss the cam plate ,
    it may require a tap here or there to remove slack to ensure accurate engagement . Like a well oiled whatever .

    The NZ terrific poll ease had WW1 era lace up knee length boots , and didnt get along with their Triumphs or their gearboxes,
    unless endowered with unusual degrees of sympatico . A rider on the Commando endowered with this footwear would
    inadvertantly produce a grauch at every shift . Clod Hoppers rather than toe action . Toes being comparable to fingers in sensitivity.
    Except amougst truck drivers . Who may not posses toes as such .

    Thus its not unkown for a previously employed transmission to be brutalised .
    HOWEVER , being robust as Triumhs generally are , at least in the larger twins,
    If its not making metal , it is likely generally sound ,
    but would likely benefit from selective fettling , as previously mentioned .
    And now you know why .

    Not to detract from previous advice .

    Looking at the spring , AND its operating length range , there should be firm and steady ( even ) pressure Through that range .
    If it only firms up through the lower part into the plunger housing , theres your probllem .
    And as its shot , giving the sping a fair heave will enable you to decipher its properties .
    So if like mine it stretches ludicrously , by the time you manadge to get it short enough to refit ,
    the sping pressure will likely be good , and ease in correctly within 20 miles of fitting .
    i.e. the shift action may be a bit stiff initially , but itll soon find its room .

    Recalling the pre unit were I think more coils of a slightly ( 20 % ? ) thinner wire .
    Once bitten twice shy . You want say 3/4 inch of compression , fitted . For a good shift .
    As was the wont after this humbling experiance ! .

    ( always save and inspect the oil s after changes , and setting for some hours. As to if theres any metalic contamination .)
     
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  6. xbacksideslider

    xbacksideslider VIP MEMBER

    Joined:
    Aug 19, 2010
    Thanks Matt
     
  7. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    So, how’s life with the Bonnie then John ?
     
  8. xbacksideslider

    xbacksideslider VIP MEMBER

    Joined:
    Aug 19, 2010
    Stalled. Wife is very ill, many of my posts on here are from hospital where I am driving and wheel chairing her.

    Changed oil lines (fuel injection hose) and installed new chain and 45 tooth rear sprocket. Oh, disassembled and tuned up the right hand headlight high/low horn switch. Found a stronger detention/plunger spring but it’s still on the bench

    Thanks for asking
     
  9. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Sorry to hear that John. Hope she gets well soon.
     

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