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Remove Top End Without Removing Engine?

Discussion in 'The Garage' started by Jim, Feb 13, 2019.

  1. Jim

    Jim The thrill of victory and da agony of da feet. Top Contributor XS650.com Supporter

    I found this tip in the Yamaha Racing Tips Manual. You slot the top end studs so you can remove the top end with the engine still in the frame. Anyone here ever try this?

    top1.png top2.png
     
  2. Signal

    Signal XS650 Junkie Top Contributor

    No but I saw a photo of an Australian XS race bike with the top end off and noted that the studs were slotted.
    Cant remember if it was in the frame still or not. Have a look around the XS 650 club of Australia website.
     
    Jim likes this.
  3. Rasputin

    Rasputin XS650 Addict

    I heard tell the studs were a very tight fit in the crankcase. Not sure if you could turn them out with a screwdriver, straight off. Velocette used the same approach on their singles. Worth thinking about.
     
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  4. Signal

    Signal XS650 Junkie Top Contributor

    I agree Rasputin the studs are very tight in the cases. They would need to be removed slotted and reinstalled for this to work.
    I think small flats milled on opposite sides of the stud top to suit a 10 or 8mm spanner would be better. There is enough thread going into the head nuts for this.
     
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  5. grizld1

    grizld1 Grumpy old man Top Contributor

    Removal of factory installed studs tends to be difficult not because they're installed under heavy torque but because of the locking compound Yamaha used. A race motor typically gets very frequent teardowns. For street/highway use, I don't know if you'd want to trust studs installed in a way that would make the slots useful.
     
  6. angus67

    angus67 Welder's penetrate deeper!!

    if we could, we would........
     
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  7. MrBultaco

    MrBultaco it ran before being parked Top Contributor XS650.com Supporter

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    I've got that same article for Yamaha XS650750 race bikes. I would bet that the engine is out and apart when the studs are notched.
    They also probably used Champion, Trackmaster and C&J frames where there is lots more room on between engine and frame. I might scan these pages and post it sometime. Has lots of racing tips including porting the head.
     
  8. Jim

    Jim The thrill of victory and da agony of da feet. Top Contributor XS650.com Supporter

    Agreed.
    On my 80 frame, there's plenty of clearance for the inner studs. The rocker box clearing the frame is another question. Just as a guess, the gap 'tween the box and frame looks to be about the same as the alignment bushings. Of course if one was to do this.... trimming a tad off the bushings would work.
     
    Last edited: Feb 13, 2019
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  9. Bigfeet

    Bigfeet to many projects

    I think Hugh posted something similar to this. I just can't remember when.
     
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  10. MrBultaco

    MrBultaco it ran before being parked Top Contributor XS650.com Supporter

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    This isn't a very good pic.(taken in 1980 when I built it), but it shows the outer studs.The Champion StreetTracker.jpg backbone was narrower than the Yamaha is.
     
  11. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    One of these days...............
     
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  12. Jim

    Jim The thrill of victory and da agony of da feet. Top Contributor XS650.com Supporter

    Drag it outta the barn and get to it.... :rolleyes:
     
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  13. 650Skull

    650Skull Dinosaur Lives Top Contributor

    talking about this to people i had an argument put to me being against doing this, due to not having the studs locked in, (as per Factory), getting the head torqued could be problematic, studs could turn in the case, and has the potential to strip the threads in the bottom case......or uneven torque
     
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  14. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    dunno, don't see a problem, turning thread at either end of the stub applies the same torque. There's deep thread in the cases, typically it's a racer, parts get used up.
     
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  15. On some old Honda Cb 750 I use to slot the top rail so motor didn't have to come out
     
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  16. xjwmx

    xjwmx XS650 Guru Top Contributor

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    Eccentric locking stud remover tool like 4g has, and I don't see why you'd need either slots or flats to get them out. Protect the threads if needed. Agreed, could be a bear to get them out the first time, w/ engine out of frame, ..but with that same tool, maybe not...
     
  17. Ipa62

    Ipa62 XS650 Addict

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    I've been putting off doing my top end, mostly because of having to pull the motor again (no space to work, no time, no....) anyway this is intriguing. found these stud pullers, upload_2019-2-14_17-4-51.png
     

    Attached Files:

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  18. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    There might be some confusion here; this thread is dealing with studs that have already been freed from the crankcase and the adhesive removed.
    In my fairly experienced opinion; you will NOT remove the studs from a stock motor with the head and cylinder still on the engine. To remove you have to heat the studs where they go into the crankcase. We ain't talking a match, play a propane torch over the stud pretty good. Some long socket extensions to get the extractor down near the base of the stud really helps.
     
  19. Ipa62

    Ipa62 XS650 Addict

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    I was also thinking of this, wondering how much torque you could apply to a tool like the one shown above and would the stud break free of the case or would the tool damage the threads. Hmmmm…. it's been more than once where a shortcut has cost more time and money.
     
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  20. 650Skull

    650Skull Dinosaur Lives Top Contributor

    +1 ............Red highlight is the bases of this thread............Not to be confused with.............. "oh ok i can do this to make my cam chain guide removal easier the first time, so i don't have to remove my motor"
     

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