Clutch Stuck - 1977 Triumph Bonneville T140v

Discussion in 'Technical Help' started by Charles West, May 2, 2024.

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  1. #1 Charles West, May 2, 2024
    Last edited: May 2, 2024
    Hi Everyone,

    Need your help! I picked up a new to me T140v about a month ago and have been doing work on it to get it running and just have it at the point where I took it out for it's maiden voyage yesterday and it ran great!

    This evening I put my gear on to go out for another ride and when I go to put it into first with the clutch handle depressed, it immediately stalled. Did this a few times until I realized The clutch wasn't working. The clutch is stuck. I've read a few forum posts about putting it in gear and rocking it back and forth (engine off of course) with the clutch handle depressed, but no luck. The clutch cable is still connected and has the same tension as always when depressing the handle, so I am at a loss.

    Two key questions: Why do you think this happened given the bike ran great yesterday? What do you think I should do to fix it / What should I try first?

    I normally start the bike in neutral but do not depress the clutch handle when starting, but have seen others indicate you need to depress the clutch handle while kicking the bike over, so not sure that's the cause.

    Really appreciate the help!
     
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  2. ManInTheJar

    ManInTheJar Member

    Feb 4, 2023
    32
    18
    Scotland
    The clutches can be a bit sticky after standing. The normal starting procedure includes kicking the bike over with the clutch depressed and the ignition OFF until the clutch frees up (it is really obvious when this happens). Failure to do this can damage the gearbox when you select a gear.

    The clutch is located between the kickstart and engine which means that when the clutch is freedom off the engine will not turn over if you depress the kickstart with the lever pulled in.

    If you are having clutch issues it is maybe time to adjust it and maybe even service it. Adjustment starts with adjusting the pressure plate run- out (critical but needs primary cover off) before adjusting the pushrod and finally cable free play.

    In addition to cable/ pushrod adjustment, routine maintenance includes lubricating the cable and ensuring it has no sharp bends.

    Deeper maintenance includes removing primary cover and cleaning plates, checking basket (notched slots, roller bearings, shock absorbers rubbers) and checking spring lengths.

    All of this will help minimise clutch stiction.

    There are a few mods which can be made to improve the clutch action including a 7 plate conversion (with 650 springs), alloy pressure plate and smoothing out any notches in the basket.

    Servicing the clutch actuator in the gearbox cover and the gear index plunger under the gearbox also make a noticeable improvement to clutch/ gear operation.

    My TR7RV gearbox has all of the listed work and mods plus a belt primary, gear changes are siky smooth now plus neutral is a dawdle to find.
     
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  3. Hi ManInTheJar, thanks so much for the information! Since my initial post, I took the primary off and had a good look at the clutch. I tried to get it unstuck by kicking it over and rocking the bike back and forth repeatedly over the course of a couple of days, but to no avail. That's why I resorted to taking the bike apart to see what was going on. I found that the nuts holding the springs down were significantly out of adjustment, with the top of the bolts sitting more than 3/8" below the slot in the spring nuts. Given the nuts were this loose the outer basket and inner hub were able to 'wiggle' independently of each other, causing the clutch to bind. This is a new bike for me so a mystery as to why those spring nuts were so loose, but guessing it was an attempt by the prior owner to achieve an easier pull on the clutch handle. I measured the plates and springs and all were well within tolerance so reassembled it.

    Now that the clutch is properly assembled and adjusted, it works well but takes significant effort to pull in the clutch lever in.

    I am now seriously considering the 7 plate conversion kit. I am in Canada and the Aerco kit is more available to me than the Hyde and it appears to have good reviews so thinking I may pull the trigger and purchase it soon, as you're right. Curious to know which kit you purchased? Appreciate it!

    Here's the link to a video I did of the work showing the process I followed:
     
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  4. ManInTheJar

    ManInTheJar Member

    Feb 4, 2023
    32
    18
    Scotland
    I also have the Aerco kit with T120 springs and this works well. Adding an alloy pressure plate at the same time also helps, these have less flex and make it easier to adjust them to run true. I have an SRM alloy plate which also uses a needle bearing on the clutch pusher.

    A point to consider when fitting a 7 plate kit is the diameter of the pressure plate,. The ID of the friction plates is larger than stock plates so make sure whatever pressure plate you use is large enough to overlap the friction plates.

    I also found that a couple of often neglected items had a significant effect on the hear change. The index plunger under the gearbox is well placed to become clogged with sludge which can gum it up affecting gear indexing and the clutch pusher mechanism collects muck and grit plus the balls can become crusty affecting clutch operation. Both need the gearbox drained which is a good time to use a quality oil.

    The index plunger is easy to dismantle and clean. Once cleaned, check the plunger tip and replace if worn, also fit a new spring if you don't know when it was previously changed. Make sure you use the correct sealing washer as the wrong once affects the plunger preload. Finally prime the plunger assembly before refitting. This all gives a more precise gear change provided the cam plate is in reasonable condition.

    The clutch pusher on the inside of the gearbox cover benefits from a good clean, also check the balls and replace if worn or rusty. Oil on re-assembly This all gives a much smoother clutch pull. NOTE check the size of the old balls and replace like for like as different sizes exist.
     
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  5. Hi ManintheJar, thanks so much for this info! I have the new clutch bits on order, so very much looking forward to installing them. Cheers!
     
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  6. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    1,133
    243
    appalachia usa
    i have found that slathering the clutch plates with white lithium grease before installing them helps them to engage smoothly.
     
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  7. Hi SpeedRattle, thanks so much for that info. Due to the amount of effort it takes to depress the clutch handle I've purchased a 7 disc clutchkit and will be installing that later today. I've soaked the friction discs in 20/50 motorcycle oil, so hopefully that will work okay. I'll keep your lithium grease tip top of mind in the event I need to open it up again. Really appreciate the advice!!
     
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  8. joe mc donald

    Subscriber

    Dec 26, 2014
    14,360
    1,000
    slough / burnham
    @Charles West
    Welcome to the family. Do hit the upload a file button bottom right. Let the inmates see the Bonnie. Joe
     
  9. Hi Joe, here's a photo of the bike. Cheers!

    PXL_20240417_204455687.jpg
     
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  10. joe mc donald

    Subscriber

    Dec 26, 2014
    14,360
    1,000
    slough / burnham
    @Charles West
    Thanks for the picture. And it is a real nice machine beautiful in fact. Joe
     
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