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Slide Hammer
May 15, 2009

helno posted:

Confirmed.

Bits of the spring fell out of the left hand dust seal so I imagine the real crank seal is hosed as well. Not unexpected since this bike sat in a shed since the mid 80's.



Is that a lean condition hole? (Meaning, the crank seal drying out is what caused this?)

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Slide Hammer
May 15, 2009

Taking care of any kind of actuated control really does wonders for every bike. Several months ago, I had to replace my clutch cable and my throttle cable at the same time, arguably the two most actuated controls. I also took that chance to replace the clutch lever. It totally changed the feel of the bike. Felt brand new.

Slide Hammer
May 15, 2009

Disconcertingly, all of my rear sprocket nuts had come loose. The sprocket had about half an inch of angular play... Yeah, I had bent the tabs down on those long tab washers! Maybe that's what stopped the nuts from working themselves completely off. Seems like it'd been like that for at least a little while. Tightened them up and re-bent the tabs as close as I could manage. I was able to do this with the wheel still on the bike.

Slide Hammer
May 15, 2009

knox_harrington posted:

I've finally got both of my wheels... and they're slightly different colours. gently caress. It'll probably look OK on the bike but I'll know, and now so will the internet.

The front disc is the SC77 type. Pics of SC59s all have a rim tape design, though obvs could have been removed.



From here, I can barely tell the difference, and I'm an artist. Which means people 10 feet away and/or even 5 mph slower than you won't be able to, either.

The wheel at the rear is already going to look darker due to being ensconced in the frame. Since that's the one that looks lighter here, they're actually well-matched. :hai:

Slide Hammer
May 15, 2009

Pushed it 4 miles when it blew a fuse and I didn't have a spare. Made the unpleasant discovery that multiple gas stations will stock 2-cycle oil but no fuses. At that point, it felt like my femurs were gonna fall out of their hip sockets, so I had to take a risk and connect the fuse terminals end-to-end in order to ride it the rest of the 4 miles home.

Slide Hammer
May 15, 2009

This is an old bike, so it had a single 15-amp glass cylinder fuse. The terminals are split collars that fit over the ends of the fuse. To connect the terminals, I just slipped them onto each other using the split in each one.

Slide Hammer
May 15, 2009

The ignition tumbler on my GN125 has worn out to the point that the bike shuts off by itself mid-commute multiple times. Reaching over to twist the key back into the < 0.5 mm contact point left with no divot to hold it has become a reflex action. I got the new tumbler in the mail recently (and the action is so nice. Funny how all of these Chinese parts are higher quality than the OEM, at least at first use/glance). Looking forward to finally changing that out this Thursday, my only day off.

Slide Hammer
May 15, 2009

Replaced my brake master cylinder again, getting rid of the weird rock-hard-lever-pull one for one that, on testing, demonstrates a more normal action. Hopefully the brakes won't drag as much on this one. It seemed like gravity made the fluid leak out of the old one too quickly, so maybe it was some kind of casting issue with the cylinder body that wouldn't seal.... whatever.

Tried to replace my worn-out ignition cylinder with another Ali Express special. First, I mistakenly ordered the six-wire version. Next, I ordered the correct four-wire version, but it lacks... taillight support. The taillight isn't on when the bike is on. I have no idea if this is a Chinese thing or not, where Chinese bikes might have an on/off switch for lights and it expects that. But, the headlight is on... Did a solder point break?? Switched back to my old jumpscare ignition cylinder with some rubber damping to help it not shut off in the middle of riding. Seems to work well so far—only one episode on the road for a month.

Slide Hammer
May 15, 2009

I love pressing old parts I kept around "just in case" back into service. The frugal bugle.

I'd had a few front brake master cylinders now that had the problem of dragging the brakes, even though they were new. Manufacturing problem? Who knows. Chinese parts, but, it can't be solely because they were made in China, considering the first replacement I got back in ~2014 was also from China and worked great. In fact, that's the one that I put back on the bike. Its reservoir had been destroyed by 8+ years exposure to UV, so I thought that I needed to buy new brake master cylinders, which is when I started having this problem.

At some point, I remembered that the reservoir, being mostly held to the master cylinder body with the reservoir cap screws, just pops off. I popped off the reservoir of one of these newer brake master cylinders and stuck it on the 2014 Chinese brake master cylinder... voilà.

Would like to know what the hell was going on with those other brake master cylinders. They started to drag when cold, then stopped when, I suppose, the friction heated up the caliper again. One was worse than the other. Maybe the caliper needs to be cleaned??

Slide Hammer
May 15, 2009

LimaBiker posted:

There is a little return hole in the master cylinder that allows the fluid to get back into the reservoir, when you release the brakes. It's tiny. If it's clogged, your brakes will drag.
You can diagnose that by intentionally making the brakes drag, and then opening up one of the bleed nipples. That will make the pressure in the system disappear, if it's caused by the return hole being clogged. If there's no change in drag, then it's the calipers.

How long have your calipers gone without internal cleaning or replacing the seals? The seals can swell up, the caliper body can corrode along the ridge that the dust/water seal sits in and squeeze the seal tighter against the piston. My experience is somewhat limited to my own 2 bikes, but if it's more than 15 years, just replace the brake seals anyway. It's not that hard of a job, and if you do it before everything jams up, it's much easier.

Disk brakes can always drag a very tiny bit. But if you ride for a while without touching the brakes and come to a stop with your non-dragging brake, they should be no warmer than like 30 degrees C - in other words, just above 'not stone cold'.

Thanks for the info. Getting to the hole on this model of brake master cylinder is difficult because the reservoir covers it up with a baffle. I had a GS 750 20 years ago where I was able to poke a strand of wire from a wire brush down into the master cylinder's relief hole to clear it, but that's not as easily done on this model. In any case, this master cylinder is working better than the other two, and I'm just wondering where the temperature element comes from.

I replaced the piston in the caliper recently because I was surprised at how cheap it was, about 3 years ago. I wasn't able to get one small nub of the dust seal all the way into its recess, though...

Slide Hammer
May 15, 2009

Changed my front tire last week and my rear tire this week. Like usual, bike is transformed, especially because the last time I changed them was 7 years ago.

Heavy wooden chairs make great bead breakers.

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Slide Hammer
May 15, 2009


Are you using the centerstand in this pic? It just looks like a jack stand and a jack. I'm interested in this because it seems like a way to work on bikes that don't come with centerstands i.e. all of them.

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