CB100: Rolling Chassis!

With 2 new CB100 top fork bolts in hand, had another go using the S90 forks.

Worked as expected, though didn't cinch everything down very tight.  At first, installed it with the S90 front wheel but then decided to test the CB100 front wheel/hub/axle but still using the early S90 forks.

Realized that the CB100 has the single diameter front axle but the early S90 forks would use the double diameter version.

So... either need to use late S90 forks (which are probably closer to the correct 1971 version) or just use the S90 front axle but with the CB100 wheel.

Unboxed the new tank and gave it a gentle clean.  Added the cheap eBay cafe seat and also the soft center stand spring.

And we have a rolling chassis!  Very cool to have her standing up on her own.  Kinda looks great with all the empty space in the frame.  Will need to preserve that as much as possible.

 

 

Roxy: Fork Oil Replaced

 

Changed Roxy's fork oil.  Was worried at first that the plug was clogged, but used a single strand copper wire to clear the muddy gunk enough to let it flow.

 Drained 125 mL and added the same amount back.

 

Forks Day

Red: drained the right fork and got a little less than 100 mL, refilled with 100

Ivy:
- right for a little less than 100 mL, refilled 100
- left was exactly 100 mL, refilled 100

Also, the right fork bolt on Ivy just spins.

Red: Epic, Forks and Leaks

Had put off these bigger jobs for a long time...

Started by draining the oil to take another look at the left cover oil leak.

Saw that there was definitely old gasket on the cover, so scraped some off and then also used 2000 grit and with cover flat on plexiglass tried to smooth it down evenly.

Went back to the regular paper gasket to get a "default" setting.  The cork-rubber gasket seemed to be holding up fine, though.

After that, swapped out the clutch.  Screen filter was VERY dirty.  Pretty much blocked solid.  Some sludge in the clutch basket trap (clutch got swapped anyway).

All that took three hours.

Then on to the forks.  Pulled just the right one and removed both of the ACE o-rings.  With wheel back on, the fork was spurting oil on every compression.

Put the ACE o-rings back but put some grease around them to try to prevent the forks from sticking.

EDIT (next day test ride results):  Unfortunately, still getting a small leak from under the left cover, but now a BIG leak coming out the top.  Did sanding the bottom introduce a warp at the top?!

Right fork still leaking but they don't stick anymore!

Clutch much better now.  No more "heavy" third kick.  Seems to start much easier, too.  Also ended up dialing the throttle screw way down.

Red: Fork Oil Stumper

Drained Red's fork oil thinking I'd be able to figure out how much had leaked out of the right side and replace it.

So was a bit perplexed when I drained exactly 100 mL out of each side.  Stumped...

Red's plug a bit sooty but ok.

Disconnected the Ivy's coil wire and cut the fuel line.

Pumped up Roxy's tires.  Need to watch out for the rust spot developing on her front fender.

Red: Fork Seal Saga, Part 3

Let's recap...

• Found the left fork leak quite early on, back in May
• Bought a pair of fork bottoms ($39)
• Absolutely destroyed one of them trying to remove the seal
• But used the other one to replace Red's left unit (Part 1, June 1)
• This seemed to stop the leak.. for awhile anyway
• Then in July, the right side starting leaking
• Bought a complete set of forks ($88, though very perished)
• Used one of the units to replace Red's right side (Part 2, July 21)
• But only a week later, found that both sides were leaking again

Realized I could gamble on eBay forks forever and it's just luck of the draw on whether I would get a decent one or not.  And forget about actually trying to swap the fork seal itself...

Then had the thought that the forks are not a precision unit.  If oil is leaking out the top, why not just try to "plug" the leak?  Thought maybe I could just add my own o-rings into the mix.

Got a bunch of different sizes at Ace for about $.80 a pop.

Had the day off of work (gotta love Summer Fridays) and plenty of time.  Getting at the forks is becoming routine at this point.

Removed both forks and swapped to the new "golden" colored springs, thinking that they were stiffer.

Then I added a #19 and a #20 on top of the fork seal unit but under the metal washer so that the spring would hold them tight in place.

Also switched down to 10 weight old (instead of 15).

Ended up being two steps back...

While it seemed to stop the left side leak, the right side was still leaking.  Not only that but the gold springs caused the forks to bind on compression and you had to force them back up into place.  Thought maybe that condition would only exist in the garage but an afternoon ride confirmed that they were binding no matter what.

Red: Fork Seal, Part II

Surprised when I realized I'd done a four-hour session.  Wasn't anything so epic, but perhaps I was taking my time.

Went through the now-familiar process of removing the seal unit from the right fork, but realized something was a bit off when I opened up the drain plug and nothing came out.

Pulled the bottom fork off and saw the opening was pretty gummed up.  Shined a light into the hole and it was completely blocked up.  Used a small allen wrench to poke around and finally saw there seemed to be not only fork muck but also some kind of residue, maybe very old gasket material.  Then used a longer bolt to clean the threads and push it out.  Sprayed the inside out with the hose to rinse it clean, then ran some WD40 through it.

Bolted everything back up and flushed it with a tiny bit more fork oil before filling it with 125mL of clean fluid.

Given how much muck was in the right, was worried same might be true on the left.  Removed the bolt and once again, nothing flowing.  Popped the bottom off and pretty much the same level of muck although no gasket residue on this one.  Just did the power rinse with the hose and the WD40, which seemed to clean it all out nicely.  Filled with 125mL.


Took a fresh look at the battery compartment.  Had hoped to use the new terminal block to attach all the positive leads together, but even though the block fit fine in the compartment by itself, once it actually had wires attached to it, it was just too clunky to fit clean.

But after untangling and sorting the wires a bit better, realized that maybe I could get away with just organizing the existing mess a bit better.  Removed the old "junction" and chopped each lead much shorter to get rid of the excess.  Also used a zip tie to lock all the positives together.

The negative bundle was the only one that attached to the battery so only those wires had to be long.  Shortened one of the kill wires and then used a bunch of zip ties to make it a little neater.

Putting everything back in, it's still a nest of wires, but when you pull them free, it's much more organized and clear where everything is supposed to go.  So good enough for now...

Still not sure why Ivy's compartment is so "empty" compared to Red's...

Also checked the plug and it was black and clean.

Garage Notes: All about Early Forks

Because for whatever reason, I always forget how this works...

The Early forks are nice and simple. 

You unscrew the fork seal housing unit (the one with the holes for the pin wrench).  Once that's unscrewed, you essentially can break the fork into its three main pieces.

The Early fork seal housing unit does have a replaceable seal, technically speaking.  But it is extremely hard to remove (and probably just as hard to install) so you're probably better off just trying to find a good complete unit instead of swapping seals.

You can easily swap out the o-ring inside the unit, though, which may help with some leaks.

Also, don't forget to always install the metal ring on top of the seal before installing (this is where the springs sit).

Also, don't forget that the springs are mounted with the narrower coils toward the top.

Red: Fork Seal Swap

One big job and lots of little ones...

The main event was swapping the left fork seal housing in the hopes it would fix the leak.  Got a couple of fork bottoms on eBay that were very perished and really almost the only usable thing was one good housing.

So the fender and wheel came off.  Then unscrewed the fork bottom from the housing.  Then unbolted the fork leg itself.

Examining the left leaky housing, it was obvious how worn down it was.  The new eBay one did look much better.

Swapped it over, flipped the spring right way up (the narrow coils go on top!) and put the fork back finger tight.

But I had also seen some weeping on the right side and sure enough, that housing was pretty perished as well.  Not having a second good housing to use, all I could do was clean it up as much as possible and replace the o-ring.  Hopefully that's enough.  At least it never leaked as badly as the left.

Added a touch over 100 mL of oil back to each side.


With the wheel off, also took a look at why the front brake seemed so weak (especially compared to Ivy's).  Didn't really see anything wrong with the brake itself, so I'm worried that maybe the drum lining is worn down, which unfortunately means a new wheel hub.  Though that kills two birds with one stone so that I could balance and true it at the same time.  A job for another day...

Also got excited fitting the speedo cable until I realized that there was no speedo gear!  Added the cable for now, but will need to wait for the part.


Then went to torque the rear flange bolts only to find that 3 out of the 4 would spin endlessly.  All I could really do was try to hold them in place with the tabs.  Will need to check them often.

Found a tiny leak from the bottom of the base plate, but it's a very slow leak.

Finally, added the new thermometer to the bars (the one that I got from an Instagram add and then took 2 weeks to arrive...)