TECH ADVICE ON POSITRON REAR DERAILLER

[Polly]

Hey there everybody on rec.tech

I am currently messing around with a very old shimano
positron rear derailler. Its a bit infuriating since I dont
really have much info on this. I was wondering if anybody
new of a website where there might be a diagram discusing
adjustment of this type of derailler. Or any type of
advice... woudl be appreciatted. Basically the derailler is
somewhat bent, that I fixed..however problem is it just
keeps shooting into the wheel. I am preplexed as to how one
adjusts the limit on one of these or perhaps that is fixed?

Thanks Polly

 

[S. Anderson]

Polly" <[email protected]> wrote in message
news:[email protected]...
> Basically the derailler is somewhat bent, that I
> fixed..however problem is it just keeps shooting into the
> wheel. I am preplexed as to how one
adjusts
> the limit on one of these or perhaps that is fixed?

I seem to recall there WAS a limit screw on there
somewhere..is there a screw in the middle of the derailleur
body? That one screw might be intended to do BOTH
limits..sort of a fixed amount of swing and you're setting
the bracket of swing. I also think some had dual limit
screws, like a normal derailleur, but I'm not sure about
that. Wish I could help more!

Cheers,

Scott..

 

[Polly]

Thanks Scott

theres no dual limit screws on this baby, or it might be the
case that they were and they are gone. I was thinking that
middle screw might adjust the limit as well. Its kind of a
weird situation as no one has really posted any diagrams as
to fixing it, I do seem to remember theres a really old
manual that might have a section devoted to it. I guess I
have to figure this one out and post the results, I was
kinda hoping Jobst or sheldon might pipe up with a response
to fixing it.. oh well

Thanks polly

 

[S. Anderson]

"Polly" <[email protected]> wrote in message
news:[email protected]...
> Thanks Scott
>
> theres no dual limit screws on this baby, or it might be
> the case that
they
> were and they are gone. I was thinking that middle screw
> might adjust the limit as well. Its kind of a weird
> situation as no one has really posted any diagrams as
to
> fixing it, I do seem to remember theres a really old
> manual that might
have
> a section devoted to it. I guess I have to figure this one
> out and post
the
> results, I was kinda hoping Jobst or sheldon might pipe up
> with a response to fixing it.. oh well
>
> Thanks polly

You know, now that I think about it more, I think that screw
sets the upper
limit. I think the chain has a disc after the last cog that
prevents the chain from falling off on the bottom.
Unfortunately, there weren't that many of those
things and they were rather problematic.

Good luck!

Scott..

 

[Dianne_1234]

On Thu, 29 Apr 2004 19:13:19 -0400, "Polly" <[email protected]>
wrote:

>Hey there everybody on rec.tech
>
>I am currently messing around with a very old shimano
>positron rear derailler. Its a bit infuriating since I dont
>really have much info on this. I was wondering if anybody
>new of a website where there might be a diagram discusing
>adjustment of this type of derailler. Or any type of
>advice... woudl be appreciatted. Basically the derailler is
>somewhat bent, that I fixed..however problem is it just
>keeps shooting into the wheel. I am preplexed as to how one
>adjusts the limit on one of these or perhaps that is fixed?
>
>Thanks Polly

My memory could be wrong, but I think the single screw
centers the range. I guess in a way that's limiting, but
I don't recall the instructions saying to set it as a
limit screw.

Try adjusting the screw while watching the effect on the
derailleur's movement. Even while not pedaling I think I
remember the derailleur's lateral position being affected.

 

[A Muzi]

Polly wrote:
> I am currently messing around with a very old shimano
> positron rear derailler. Its a bit infuriating since I
> dont really have much info on this. I was wondering if
> anybody new of a website where there might be a diagram
> discusing adjustment of this type of derailler. Or any
> type of advice... woudl be appreciatted. Basically the
> derailler is somewhat bent, that I fixed..however problem
> is it just keeps shooting into the wheel. I am preplexed
> as to how one adjusts the limit on one of these or perhaps
> that is fixed?

There is a single adjusting screw. It's accessed through an
aperture in the outer body plate. Double check, by getting
your head directly behind the changer, that the thing is
vertical and parallel to the chainrings. And oil the cable!
They are pricey!

--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971

 

[Leigh]

A Muzi <[email protected]> wrote in message news:<[email protected]>...
> Polly wrote:
> > I am currently messing around with a very old shimano
> > positron rear derailler. Its a bit infuriating since I
> > dont really have much info on this. I was wondering if
> > anybody new of a website where there might be a diagram
> > discusing adjustment of this type of derailler. Or any
> > type of advice... woudl be appreciatted. Basically the
> > derailler is somewhat bent, that I fixed..however
> > problem is it just keeps shooting into the wheel. I am
> > preplexed as to how one adjusts the limit on one of
> > these or perhaps that is fixed?
>
> There is a single adjusting screw. It's accessed through
> an aperture in the outer body plate. Double check, by
> getting your head directly behind the changer, that the
> thing is vertical and parallel to the chainrings. And oil
> the cable! They are pricey!

Hi Polly i have some diagrams and information on adjustment
i could e-mither to you if you are interested let me know
and i will try and zip it up for sending Leigh