Tr7 Transmission

Discussion in 'Vintage Classics' started by watourec, Sep 4, 2021.

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  1. watourec

    watourec New Member

    Sep 4, 2021
    1
    3
    kentucky
    I have a 1977 TR7 I have been restoring, off & on, for a while now. The engine and transmission were supposed to be OK when I bought it. Most of what needed restoring was cosmetic, and suspension modifications, the previous owner had semi "bobbed or chopped" the bike but never completed it. It had not been started for 3+ years when I bought it. First I got it prepared to start, which it did and ran not great but just OK. I did not check the transmission other than seeing if it would shift, which it did. I therefor went on with the restoration, which I eventually finished. It was at that point that I was ready to test it on the road, and when the problem appeared. I cannot get the bike in neutral when it is running, it will not go into neutral shifting up or down no matter how softly I try to shift. It will shift in and out of all the gears smoothly, and it will shift into neutral easily when the bike is not running. I have removed, cleaned and reinstalled the clutch plates and balanced the spring pressure, and adjusted the cable, the basket showed very little wear, almost none. Does anyone know what my problem is, or what I am missing?
     
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  2. littleade

    littleade The only sane one here
    Subscriber

    Mar 17, 2015
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  3. Iceman

    Iceman Noble Member

    Apr 19, 2020
    772
    443
    Lancashire
    I would recommend you fit a 7 plate clutch conversion, it consists of 7 new plates with a smaller friction area plus one new plain plate. Compared with standard it reduces the problems of sticking, slipping, swelling, dragging and heavy operation (provided the other components are in good condition). To be used in conjunction with your existing 6 plain plates. You need to make sure the plain plates are completely flat with no sign of warping. Also use Bonneville T120 springs. This will totally improve the way the clutch feels, it will be lighter, the gear changes will be a lot smoother and you will be able to select neutral when you are stationery. Triumph started fitting the 7 plate clutches later on due to cure the issues you describe. You mention you have balanced the spring pressure, by that I take it you mean "run out", the best method is (with primary case removed) and turning the engine over with the kickstart, look at the plate and see if it really is running true, if not adjust the springs individually until it runs true, I use a DTI as it gives almost 100% accuracy.
     
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  4. Dartplayer

    Dartplayer Crème de la Crème

    Aug 8, 2018
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    Hi Watourec and welcome to the forum :cool: I hope trying the outer plate fixes your issue, looking forward to seeing your ride pix :p
     
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  5. darkman

    darkman Crème de la Crème

    Oct 26, 2015
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    My thoughts if the above has been checked are the cam plate or detent as its a well known problem.
     
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  6. watourec

    watourec New Member

    Sep 4, 2021
    1
    3
    kentucky
    Can you go into more detail about a cam or detent. Where and what they are, I am ignorant when it comes to a transmission, I know how to change the gear oil and that's about it.
     
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  7. watourec

    watourec New Member

    Sep 4, 2021
    1
    3
    kentucky
    Yes I "ran out" the springs. I used a straightened out paper clip attached to one of the sidecase screws and bent as a pointer just barely NOT touching the pressure plate edge. I then aligned the pointer to the plate where one of the spring allowed the plate to be the farthest out, then adjusted the other 2 springs out as I slowly kicked the engine over until the plate had no wobble. What is a DTI?
     
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  8. darkman

    darkman Crème de la Crème

    Oct 26, 2015
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    Hi, the cam plate moves the selector forks through the gears and holds them in each gear inc neutral and the plunger detent holds the cam in the selected position, there are plenty of online pictures and video's showing it all, just fitting a new detent plunger might cure the problem but i would strip the box and inspect the gearbox to be on the safe side as there are also other parts that could be worn.
     
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  9. joe mc donald

    Subscriber

    Dec 26, 2014
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    Watourec
    Welcome to the family. Yes i think i would have to agree with Darkman. And the seven plate clutch s are great. Drop some molly slip into the box to see if it eases up a bit. But i do feel you will end up stripping.
    Joe.
     
  10. watourec

    watourec New Member

    Sep 4, 2021
    1
    3
    kentucky
    Thanks, I also have a 78 Bonneville, I'll may take the detent from it and compare the two as I have no problems with it, or maybe I'll just order a new detent and spring if they aren't too expensive. It will be awhile before I will be able to start the bike anyway, because the last time I had it running,(last year) the head gasket blew on the left cylinder. Maybe since it had been sitting so long? Had the head checked out, no problem found. I will also buy a 7 plate clutch kit, maybe one for my Bonneville also. It will take awhile as I have too much other stuff to do to work on a bike every day, or even every week!
     
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  11. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    517
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    appalachia usa
    shortcut. listen to darkman, but think about this too:

    unscrew the hex plug on the bottom of the crankcases and remove th ecamplate detent spring assembly

    pull out the plunger and the spring and drop two 10-32 nuts into the plunger housing to preload the spring a bit.

    see whether that improves your ability to find neutral.

    else you may have a worn-out or incorrect plunger, as darkman suggested
     
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  12. Iceman

    Iceman Noble Member

    Apr 19, 2020
    772
    443
    Lancashire
    Hi watourec, The dial Test Indicator (DTI) is a sensitive instrument having a graduated dial and an indicating hand which is connected through a system of multiplying levers, or gears, to a contact point that is fastened to the end of a spindle. The contact point is placed in contact with the workpiece. Any movement of the contact point is transmitted through the spindle and measure run out, it is extremely accurate, for example if you experience "pulsing" at the brake lever you can use the DTI to check if the brake disk is warped. In your case it would give an accurate reading so you could readily see which spring or springs need adjusting to bring the clutch into alignment, much more accurate then "rack of the eye". Whilst you can improvise with all manner of techniques and they will work to an extent, they cannot give the same accuracy as a DTI. I have attached a link for a site in the USA so you can get a look at them, the prices are ok as well. Ride safe all.
     
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  13. watourec

    watourec New Member

    Sep 4, 2021
    1
    3
    kentucky
    I have ordered a new spring and detent. I can only hope they are correct. It seems there are at least three versions of each depending on the year of manufacture. MY TR7 is a very late 1977 while my Bonneville is a very early 1978. In fact according to the serial #s they were built less than 4 months apart. Therefor I am hoping the part #s in my 78 parts book will work well in my TR7. If that doesn't work I will try your 10-32 nut fix. If that doesn't work then I will have to disassemble the gearbox, which I really really do not want to do.
     
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  14. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    517
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    appalachia usa
    theres another aftermarket plunger with a ball bearing tip. people say they work well. i have one but the motor its going into is still in little pieces all over the shop
     
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  15. Iron

    Iron Guest

    #15 Iron, Sep 8, 2021
    Last edited by a moderator: Sep 8, 2021
    I've just installed a 7 plate on a '77 T140V as the one installed in the '72 was so much better. The sticking clutch and dragging are improved a lot. The dragging almost gone at high temperatures. The clutch still sticks after standing for a week or so but is easily released with one or two kick overs.
    It's still a bit touchy at finding neutral but easier done while rolling, there's even an extra one between second and third now :kissing:. I've ordered a new ball bearing plunger (not had one before) and will let ya'll know if that makes anything easier.
     
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  16. Iron

    Iron Guest

    #16 Iron, Sep 10, 2021
    Last edited by a moderator: Sep 10, 2021
    New ball bearing plunger came today. Supplied with installation instructions and a new ally washer, cor. Even though the bike has been standing for over a week the clutch wasn't stuck at all. That'll be the new 7 plate - much better. :)

    0001.jpg

    Installed immediately, obviously. Couldn't be arsed to drain the gearbox as I had a cunning plan. The large long headed bolt is the plunger assembly and the smaller twin bolts are the drain and level bolts.

    0002.jpg

    My plan was to take out the plunger and stop the hole up with some rubber bungs I have. (I used to use them when painting up hip flasks as personal remembrance pieces that looked like war commission gravestones). I forgot they have a hole through the middle. FFS.

    0004.jpg

    Here's the removed plunger and spring alongside the new ball bearing plunger.

    0003.jpg

    Give all a clean, assemble and whack the new plunger in. Only lost about half of the oil so the cunning plan worked a bit. Refilled to level through the fill hole.

    0005.jpg

    Typically, it's pouring down so I bombed around the garage. To be honest, I don't think it's any different but will report back once it stops raining and I have a poodle about. :expressionless: Over...
     
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  17. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    517
    143
    appalachia usa
    maybe it will improve shifting harder?

    i have a 1970 4 speed that bounces out of gear if i shift at a a high rpm, 7000 and above. i solved the problem by shimming and and counting a full second beteeen shifts.

    maybe the ball bearing will hold position better
     
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  18. Iron

    Iron Guest

    Yep. I'll have a poodle and maybe shim the spring just to see how it feels. Don't want to bind the spring though. There can't be much room though once it's screwed in tight.
     
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  19. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    517
    143
    appalachia usa
    mine fully retracts into the plunger housing even with shimming
     
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  20. Iron

    Iron Guest

    Well, that works. Snickety McSnickface. Very positive feel to the gear lever now. Neutral is exactly where it should be, gearchange is very positive, no dragging, no slipping. Luvly.
    I shot off to the Nailsea Bike Show this morning and it was mobbed. There was even a queue to get into the overspill car/bike park. I was enjoying the ride so much I turned around and went for a jaunt around the Somerset Levels to see where King Arthur was buried. :) Over...
     
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