Clutch Assembly Etc

  • 13 Dec 2020 2:10 PM
    Message # 9426654

    My Winter Project for 2020:

    The last few times I rode my motorcycle (1973 Tiger 750) for the 2020 season.

    I notice more noise than normal from the Primary side of the engine - this noise was at slower speeds approximately 35-40 mph. I tightened up my primary & final drive chains & it did not fix noise. The motorcycle had good performance.

    My motorcycle has approximately 62,000 miles & I have owned since May 1977. It is on its 3rd Primary Chain. The first two I replace at about 20,000 each, so I figure it is probably time for a new Primary chain.

    I currently have the Primary Chain & Clutch Assembly off of the motorcycle.

    I disassembled the Clutch Assembly & I am currently inspecting the components & would like your comments etc, since I am no expert:

    The Clutch Basket/Housing; sprocket teeth appear in good condition, the inside slots for the clutch plate tabs have peaks & valleys (which maybe normal & I could file down), the outer race for the Roller Bearings measures within tolerance (mean condition) using my dial calipers - I can see impressions or color on the race where the rollers have been.

    The 20 roller bearings all measure at correct size: .250 Diameter

    The clutch Hub ~ Inner Race for roller bearings - measures low limit in some spots & .002 out of tolerance (under size) in other spots. The shop I retire from last year, would probably chrome & regrind the race for me, but due to Covid they may not want me coming to the shop?

    The Rebound Rubbers look like they have been melted into place & the rubber even covers up most of the Shock Absorber Spider. I think the rubbers may be hard to replace, I did find a YouTube where they mounted an old hub in a vise & used as a fixture to load the Rubbers.

    The Clutch Center: the outside slots for the clutch plate tabs have peaks & valleys (similar to clutch basket/housing).

    Anyway, I think my best option might be to replace the whole clutch assembly, which according to the internet is part #57-4903. Baxter Motorcycle appears to have in stock for $675, others are listed cheaper on the internet but come from Overseas & may not be same quality etc? It seems to be $100 plus over others listed? British Cycle Supply - I think has listed for $550 approx, but I don't think they have in stock?

    Baxter seems to have all the other components such as new Adjuster Shoe. But I think they are out of "Clutch Operating Rods" but my existing Rod seems to be in Good Condition. Do we get any club discount from Baxter?

    I learned years ago not to reuse the Lock Nut that holds on the Clutch ~ I watched a YouTube recently that the person used Red Loctite, but he was reusing the old nut.  I will use a new Lock Nut but should I use Loctite too?

    Also of concern - if I purchase a new assembly - the new clutch hub may locate differently on the Tapered portion of input shaft to the transmission. According to the Workshop Manual the primary chain needs to be in line w/in .005 & checked with a straight edge. There is a shim between my engine sprocket & crank bearing.  Does anyone know how much this can vary? The work shop manual has shims listed #70-8038 (.010) & #71-2660 (.030) ~ I will order a few shims & fit at assembly.  


    Don Chambers

    Just a Historical note: back in about 1979 the "thrust washer" broke in the clutch. I took the clutch assembly to Don Henderson Triumph Dealer & they installed a new "thrust washer" for me.

    Last modified: 13 Dec 2020 2:16 PM | Don Chambers
  • 14 Dec 2020 9:38 AM
    Reply # 9428481 on 9426654
    Robert Harris (Administrator)


    Before replacing the whole clutch, I would get new rubbers and a new thrust washer. Classic British Spares, one of our Gold Sponsors, has the drive and rebound rubbers in a set for $16.95 and the thrust washer for $15.50.


  • 15 Dec 2020 10:14 AM
    Reply # 9431486 on 9426654


    Sounds like a good idea!

    I don't need to throw the baby out with the bath water.

    I will inspect the Clutch Plates & Springs too.


  • 05 Feb 2021 8:07 PM
    Reply # 10064708 on 9426654


    I bought new Clutch Plates & have two questions:

    1) Do you think it is a good idea to soak the Friction (Bonded) Plates in oil before installing

    2) Also, I purchased a New OEM style Locknut to secure the clutch.

    I don't think it is necessary since it is a New Locknut, but should I add Loctite (blue 243) to the nut?

    The torque spec is for a dry thread, so maybe no Loctite is better?

    p.s. - I replace my Clutch Hub Complete Assembly - the spider for the rubber cushions had worn deep  grooves into the inside end plate.  I replace the tapered mounting sleeve too, so then I had to add additional shims to the engine sprocket for proper chain alignment. When the weather warms up I will complete the project in my garage. 

    I hope you are all doing well - Sorry about Charlie! I talked with him last summer at a Car Show.

    Anyway, I appreciate your advice.


  • 08 Feb 2021 9:47 PM
    Reply # 10070881 on 9426654
    Robert Harris (Administrator)


    Check the Bonneville Shop

     measure the diameter of the 57-0394 roller bearings. These are .2495”-.250” in diameter new, so if the used bearings measure less than .245”, it is recommended to replace them, as they may contribute to excessive wobble in the clutch basket.



























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