Can't push thumbshifter past 4 of 9 cogs

[Damage98]

[ichitan]

There are various possibilities. Maybe the cable is not sliding freely. You may be able to resolve this by putting oil down inside the cable. You may need to replace the cable. Maybe it is just a long way out of adjustment.

I suggest keeping the bikes and fixing them up. New bikes break much more than older bikes.

[ReapThaWhirlwind]

That relic would fetch a pretty penny for the style and vintage.

I had to look it up, since lol, in 1996 I was 9 years old.

You could probably get as much for it now as it was brand new in 1996 ($1,800).

You do know how to index the derailleur, right? Undo the cable, dial all the barrel adjusters in all the way. Reattach the cable with a slight tug, just enough to remove the basic slack from the cable. Start dialing out the barrel adjuster and test the shift. If it doesn't shift, dial it out some more. Tune it from there for performance. Check the limit screws and dial them all the way out, then in until they touch and push the hammer inside just slightly. The Low Limit Screw needs the gears to be shifted all the way up for this, and the High Limit Screw needs to be shifted all the down.

Possibly humidity and heat have dried up the mechanism. Undo the face plate shoot some lubrication in there. Lube the pulleys and the hinges of the rear derailleur. I would personally get some ceramic pulleys to replace the old ones. They're about $25 CAD or so. If it's really trashed, you can get Alivio 9 speed, or Altus 8 speed shifters dirt cheap all over Amazon or AliExpress. If the brakes are hydraulic, you'll want to take them to a shop to be bled. That's going to run about $40 CAD. I'd also put fresh grease in the hubs, and I do that myself, but most shops might tax you up another $40 CAD at least.

[enkei]

Nice classic bike!

It's possible, but unlikely, that the problem is at the shifter.

More likely, you need a new cable and housing and/or the rear derailleur needs servicing.

However, you can start by watching this Park Tool video to get a better idea of what's involved in getting your shifting to work.

It might help us if you could post a few closeups of the rear derailleur so we can see the condition.

The first step is to create lots of slack in the cable to the rear derailleur, either by slacking it off at the cable adjusters or by disconnecting the cable. Then, you can try moving the derailleur in and out with your hand to make sure a limit screw isn't stopping it from reaching all gears. You also need to check that the derailleur hanger is straight. When you've verified that the derailleur moves freely in both directions, you can proceed with the next steps, as per the Park Tool video.

With a bike that old and neglected, I personally would want to go through every element of the drivetrain to ensure it's within specification and operating properly. So, I would remove the cables and housings, service the front and rear mechanisms, clean up the cable adjusters, lubricate everything, etc. If you're new to bike servicing/restoration, however, it's probably better not to pull everything apart, as you might end up with too big a puzzle to tackle.