Starter clutch repair/mod

Discussion in 'User Mods' started by cd vemaxis, Nov 30, 2019.

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  1. Nov 30, 2019 #1

    cd vemaxis

    cd vemaxis

    cd vemaxis

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    I wanted to post a thread on my starter clutch repair/mod in case it might help someone. I have done some searching, and I have never seen a permanent fix for this, although many people may have already found one.

    You all know the problem of the starter clutch loosening up. Nothing locates the starter clutch in position on the rotor. It is up to the friction of the three bolt heads to hold it in position. This will never hold, and it doesn't. That is why the bolts are staked, and not just loctited. They knew at the factory it would come loose. The starter clutch starts to wiggle around, and the three clutch rollers destroy themselves. It eventually sounds like a box of rocks, and then you can't start your bike.

    This is just my opinion on this situation. There is nothing wrong with the design of the starter clutch. The problem is the way it is attached to the rotor. There should be dowel pins holding it in position, just like when you bolt crankcase halves together. Why Yamaha left these out is beyond me. Maybe they thought theses bikes would be blown up at the drag strip long before the starter clutch gave out? I don't know.

    If you just replace the starter clutch, it's going to happen again. So here's what I did. I bought the cheapest replacement starter clutch off ebay. The quality seems fine to me. I set everything up in my mini mill, and indicated the starter clutch concentric to the rotor. I located two spots where I could drill new holes, 180 degrees from each other, and centered. This maintains the balance of everything. I drilled and reamed holes for 1/4" dowels, and pressed them in. I then replaced the bolts as they normally would be, and staked them in.

    In this picture, the right dowel has been pressed in place. The left hole has not been drilled yet.

    20190602_171942_small.jpg

    In this picture, the left hole has been drilled, but the dowel is not yet pressed all the way. The duct tape is just to keep chips out.

    20190602_173606_small.jpg

    I have only ridden one summer on this, which, for me is less than 1000 miles. So far, it is working perfectly. Please let me know what you think.
     
  2. Nov 30, 2019 #2

    cd vemaxis

    cd vemaxis

    cd vemaxis

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    On the operating table.

    20190428_180841_small.jpg
     
  3. Nov 30, 2019 #3

    one2dmax

    one2dmax

    one2dmax

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    Or some may find it easier to simply use larger headed bolts
     

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  4. Dec 1, 2019 #4

    Julian Tomkins

    Julian Tomkins

    Julian Tomkins

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    for those of us that do not have milling machines or expert knowledge, what do larger headed bolts do :)
     
  5. Dec 1, 2019 #5

    cd vemaxis

    cd vemaxis

    cd vemaxis

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    Yes, I did read about that solution, but opted to go the dowel pin route. I was concerned that it is still the threads of the three bolts that are taking the starter torque.

    Do you fix yours this way? Did it hold up long term? It is definitely an easier way to go about dealing with this issue than what I did.
     
  6. Dec 2, 2019 #6

    one2dmax

    one2dmax

    one2dmax

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    We do a completely different solution. More expensive but permanent.
     

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  7. Dec 2, 2019 #7

    one2dmax

    one2dmax

    one2dmax

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    The larger headed bolts help prevent the rocking back and forth around the axis like the stock headed bolts do (which only exert clamping pressure to the body of the clutch).
     

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