Can someone help me understand adjusting a Dura Ace AX derailleur.

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09-01-20 | 09:57 PM
  #1  
I have the instructions but can't seem to understand which screw is which on the diagram.
Is the gold screw in the photo the center adjustment screw? And then there is a select screw.
I can only find one other screw on the derailleur and it is the one right above the center adjustment
screw> It looks in a different place in their diagram. Here is a photo and the diagram.

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09-01-20 | 10:32 PM
  #2  
The screw in the upper body of the derailleur is the high-gear limit screw. Adjust the upper and lower limit screws, attach the cable, then use the "select screw" to fine tune the adjustments on the cogs.

I think. It's been nearly 40 years since I worked on one of those.
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09-01-20 | 10:50 PM
  #3  
Quote: The screw in the upper body of the derailleur is the high-gear limit screw. Adjust the upper and lower limit screws, attach the cable, then use the "select screw" to fine tune the adjustments on the cogs.

I think. It's been nearly 40 years since I worked on one of those.
There is no high or low limit screw. The only 2 screws are in the photo.
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09-02-20 | 10:31 AM
  #4  
Not to be flippant but if there are only two screws turn them and see what happens.
And if nothing happens turn them untill something does happen.
Be careful and take the weight of the screw by moving the derailleur by hand to a different position.
Use a good screwdriver because you don't want to strip those.
Bye the way I have never worked on one of these.
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09-02-20 | 10:51 AM
  #5  
There may not be any limit screws. But not certain. This is pre-indexed shifting and small cassette stack width.

Not sure but one of those screws you are talking about is the hold fast for the cable, isn't it? The smaller might be controlling how the pulley wheel springs back to a different position with shifting.

This type DR design was a one-off thing for Shimano back in the day. Probably just being ready to go in different directions if DR's of a different brand and design seemed to be the markets leaning.

This is the AX II. Not sure how helpful it is for yours........

https://si.shimano.com/pdfs/si/SI-M-86-000-00-ENG.pdf
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09-03-20 | 02:29 PM
  #6  
IIRC, one of those screws sets the derailleur to one of a number of # of cogs. It can be adjusted for 6 or 7 cogs. Also, I believe it was sort of index in theat the indexing was in the derailleur not the shifter.

When I set mine up, I used one screw to limit the travel to the largest cog but not beyond. I believe it's the small screw up near the mounting bolt. The other screw sets the # of cogs. Six cogs were the original Dura Ace AX number.
Cheers
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09-03-20 | 02:47 PM
  #7  
Quote: There may not be any limit screws. But not certain. This is pre-indexed shifting and small cassette stack width.

Not sure but one of those screws you are talking about is the hold fast for the cable, isn't it? The smaller might be controlling how the pulley wheel springs back to a different position with shifting.

This type DR design was a one-off thing for Shimano back in the day. Probably just being ready to go in different directions if DR's of a different brand and design seemed to be the markets leaning.

This is the AX II. Not sure how helpful it is for yours........

https://si.shimano.com/pdfs/si/SI-M-86-000-00-ENG.pdf
that sure looks to me like it matches what the OP has really different approach with no high low...... the whole AX group was a bit that way
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09-03-20 | 03:38 PM
  #8  
Shimano Bicycle System Components (1982) page 25
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09-03-20 | 04:45 PM
  #9  
Seems different in that you adjust the derailleur pully for each individual gear even though it is a friction derailleur.
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09-06-20 | 09:21 AM
  #10  
The instructions I posted don't make sense... If you adjust the pully for each gear doesn't each adjustment change all previous adjustments?
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09-06-20 | 04:10 PM
  #11  
take it off hold it in your hand and try to understand what the screws do.

RD really have a inner & outer stroke limit screw..
some have a B screw that forces it to rotate to increase inner clearance over low gear cog...

Found any more source material on this your self, yet?


1st bike you worked on? If so, it's an odd one to begin with ..

pick up Lennard Zinn's road bike mechanics book and a few more titles.. to understand the basics..






...
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09-06-20 | 06:04 PM
  #12  
Quote: take it off hold it in your hand and try to understand what the screws do.

RD really have a inner & outer stroke limit screw..
some have a B screw that forces it to rotate to increase inner clearance over low gear cog..
This derailleur is not like that,
See page 25
Shimano Bicycle System Components (1982)
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09-07-20 | 01:23 PM
  #13  
Quote: This derailleur is not like that,
See page 25
Shimano Bicycle System Components (1982)
Nope it's not like that .After messing with it a while I notice each gear has what
I would call a notch in the derailleur itself no click in the shifter and not a strong notch
but you can tell when it hits the next gear. Kind of between a pure friction and an indexed
system. I haven't ridden it enough to tell if I really like it. I do like friction shifting though.
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