Waking up dad's TX650 in Colorado

[Leadville Bill]

Thanks for the link Gary. So it looks like I can order the kit from Partzilla that will work with a 73 TX650 provided the bore isn’t too corroded. I’ll pull that stuff out and see if it’s salvageable. I noticed the reservoir float isn’t available for the MC. What is the purpose of the float? I assume the system would work without it?

 

[gggGary]

Not really a float? the cap has a diaphragm.

 

[Leadville Bill]

OK. I guess I’ll leave it alone at the moment and concentrate on the piston removal.

Got a “squirrel” question. I was discussing the brake work with my other brother (a mechanic) and sharing photos and he was asking what the black knob was on top of the steering column. Figuring an easy answer, I looked in the TX650 Owner’s manual, my Haynes book and a couple other Yamaha sources and while some of them had photos of it, I didn’t see any mention of what this piece was called or what its purpose was. Can you guys educate me on this item? A photo of my freshly-washed bike showing the knob in question.

 

[Jim]

It's the steering damper.

 

[gggGary]

If the steering bearings and front tire are in good nick it's not really needed. But if the bearings are loose worn notched and or the tire is cupped a nasty front oscillation can ramp up at speed. Tightening the damper can reduce that. I had it happen in my feckless youth on a 71. Occurrence and amplitude are exacerbated by weight carried on the back of the bike.


exacerbate /ĭg-zăs′ər-bāt″/
transitive verb To increase the severity, violence, or bitterness of; aggravate.

 

[Wagner73]

Not really a float? the cap has a diaphragm.

And as mentioned previously, it "looks" like your cap has the diaphragm and plastic support ring within it in this pic(?).

 

[Leadville Bill]

If the steering bearings and front tire are in good nick it's not really needed. But if the bearings are loose worn notched and or the tire is cupped a nasty front oscillation can ramp up at speed. Tightening the damper can reduce that. I had it happen in my feckless youth on a 71. Occurrence and amplitude are exacerbated by weight carried on the back of the bike.

Thanks for the explanation gentlemen. So which direction do you turn it to “tighten”? I spun it one way for a few revolutions and then the other way and I couldn’t feel anything tighten up. Maybe it can’t be felt when the bike is stationary?

 

[Leadville Bill]

And as mentioned previously, it "looks" like your cap has the diaphragm and plastic support ring within it in this pic(?).
View attachment 371166

Hoping that’s the case. Someone on the thread implied some parts were missing and I interpreted that to mean inside the reservoir, Maybe he meant something else.

 

[Wagner73]

Hoping that’s the case. Someone on the thread implied some parts were missing and I interpreted that to mean inside the reservoir, Maybe he meant something else.

Well, the reservoir looks quite groty, but I don't think anything's missing. And you'll have to take the diaphragm out of the cap to see what it's like (the plastic parts are NLA but the rubber diaphragm is available).

The balance of the internal piston parts, etc are available. FWIW, I have had good luck with Brakecrafters rebuild kits.

Finally if the piston bore is slightly marginal, a gentle cleanup with an appropriate ball hone sometimes works well

 

[Leadville Bill]

Well, the reservoir looks quite groty, but I don't think anything's missing. And you'll have to take the diaphragm out of the cap to see what it's like (the plastic parts are NLA but the rubber diaphragm is available).

The balance of the internal piston parts, etc are available. FWIW, I have had good luck with Brakecrafters rebuild kits.

Finally if the piston bore is slightly marginal, a gentle cleanup with an appropriate ball hone sometimes works well

That’s encouraging. Dumb question- if you hone the piston bore, don’t you increase the clearance around the piston and increase fluid loss between the bore sidewalls and the piston? How much can you hone it before it negatively affects brake response?

 

[Wingedwheel]

I’ve used a small brake cylinder hone with good luck. One thing that wasn’t mentioned if the wheel caliper is froze up getting it moving with a c-clamp and then working it back and forth between air and clamping. Some members prefer a grease gun, I just don’t like cleaning the grease out. Just make sure if you use air put a rag or something over the caliper half because the ‘pop’ can be pretty crazy.

 

[Wingedwheel]

I will also say I’ve used the MC kits and been able to just clean them as well but the advantage of the kits is they have the rubber dust cap to put over the retaining clip.

 

[Wagner73]

All good info above ^^^^!

As far as honing goes, I would not hone unless the bore is questionable. That said, a gentle honing with an appropriate sized hone and WD-40 (or brake fluid) many times comes up quite good.

 

[Jim]

Cut a slot in a 1/4" bolt (or rod), cut the head off, slot some red scotchbrite in it and you have an excellent cylinder hone for things like master cyl bores. Nice and gentle on aluminum. Easy on the wallet too.

 

[gggGary]

Cut a slot in a 1/4" bolt (or rod), cut the head off, slot some red scotchbrite in it and you have an excellent cylinder hone for things like master cyl bores. Nice and gentle on aluminum. Easy on the wallet too.

View attachment 371217

Same, with a dowel and 600 or 1000 grit, wet.

 

[Raymond]

When the bore is not too bad, you can clean it up with solvol - other metal polishes are available - and if that's not enough move on to more aggressive methods.

 

[Leadville Bill]

OK. I got as much off the MC assembly as I could, but I can’t figure out how to get this brass sleeve out to free the handle. I assume once that’s out I can gently drive out the remains of whatever seems to be stuck in the bore. Thoughts?

 

[Raymond]

Do you mean the lever pivot? Mine doesn't have the brass sleeve, might have been fitted to deal with a slack pivot - looks like it wants to be driven out

 

[gggGary]

Do you mean the lever pivot? Mine doesn't have the brass sleeve, might have been fitted to deal with a slack pivot - looks like it wants to be driven out

This is a 72-73 M/C with the brake light switch held on by the lever bolt.
A cotter pin at end of lever bolt is not shown.
To remove the lever from the housing; the brass bushing is threaded onto the bolt, the steel sleeve is a slip fit, remove the cotter and nut, pry the brake switch off the retaining pins. Using aluminum or brass to protect the threads, tap the bolt and brass bushing together up out of the housing to free the lever.

or @GLJ can chime in.

 

[Wagner73]

I assume once that’s out I can gently drive out the remains of whatever seems to be stuck in the bore. Thoughts?

Umm, no. There is a circlip, etc underneath the rubber boot on the lever end. You must remove that in order to release piston, spring, etc. There will be no joy in driving anything out from the banjo end. And the circlip is often a super PITA to remove.