Western Flyer 10- spd with Shimano positron shifter and disc brake, help please

[genesmachines]

I recently purchased this bike, it looks to be 70s-80s, and am working to fix it up for resale. I need help to find the model of the shifter so i can adjust it so it goes in all gears properly. Its a 2 cable push-pull deal, if i adjust it to go in highest gear, it won't go in lowest. the chain tightener runs at an angle to the gears, is this normal for this shifter? I am a single speed guy so I know enough to be dangerous. I tried to show this in pictures. Also the disc brake stops like its working in poop, can this be made to work better. It looks to be about 1/16" space between pad and rotor with cable loose. Any help will be appreciated. Thanks much

 

[bloo]

One thing that stands out is that the jockey wheels don't look parallel to the freewheel sprockets. That is universally wrong, positron or not.

If that is not a trick of the camera, then something is bent. If the derailleur hanger is part of the dropout, the dropout might be bent. If the derailleur has a claw, that might be bent.

I don't know much about positron, but I would start by getting that in line.

 

[sykerocker]

Gotta agree with bloo on this one, you definitely need to figure out where the bend(s?) is (are?).

The main reason for this is that the Shimano Positron was the first ever commercially available indexed shifting, and, as any other form of technology that 'first' and 'new', there's usually the too seldom mentioned third adjective: 'half baked'. This design is usually considered more a curiosity than anything else, if you're serious about wanting to fix and flip the bike (it's going to be for minimal gain), you're better off digging thru your junk box and finding an old Shimano Eagle and a equally cheap downtime shift lever. It'll work a hell of a lot better, and give you less risk of a customer complaint once the sale is done.

Do not, however, throw out the Positron and lever. That is something worth keeping and cleaning up as a bit of cycling history. Just not as a useful bicycle part. There's a reason why the line disappeared within two years of introduction, to be replaced by SIS. Which worked.

 

[Archie Sturmer]

Maybe a bit of gentle persuasion will bend the part back into alignment.
I was thinking maybe laying the bike on its side and using a little heel, foot, or leg power.

And maybe a light sanding of the friction surface of the rubber brake shoes?

Is the bike frame a Murray built?

 

[genesmachines]

yes its a murray, just checked, I noticed the rims are Wald S-6 and have "287 76" stamped on them. Would that be the date of mfg making them 1976? My bending of the railleur was too persuasive and messed it up so will try a different one on it. Will try to do a better job on the brake!!

 

[The Spokemaster]

sykerocker ....what he said ....the first 3 letters in the word 'Positron' say it all​

 

[williebill]

Late to the party, joined today, and having a ball roaming around the site. I've been a bike dealer for 47 years.
Positron is only adjusted to line up 3rd position to the middle sprocket. No traditional high-low adjustment. Compared to later SIS, they did suck. But they could work. Got a few of those pieces around here somewhere.
Took at least 50 of those brakes off back in the day and replaced with regular sidepulls. Wish I hadn't thrown them all away. The cable was always too long and sloppy to make them work well. Maybe a piece of 5mm SIS housing would make them work better, with less mush. Always wanted to try that, never did.
Got a ton of old stuff I'm going to list for sale as soon as I get it all in one place. At 70 years old, thinking about retirement a lot these days.
Sorry if dragging up old threads is a problem.