Run Ivy Run: The Sound of Catastrophic failure

Session actually started off very well.  I installed the stock air filter along with the S90B carb.  Everything went together very nicely.  This is the newish airbox, plus one good cover from the Viola original, plus a new repro air filter for 4-into-1.  Also confirmed the needle is in the middle position.

Before starting the next job of replacing the rear sprocket, I figured I'd torque the head bolts - a little job that just needed doing.

I use a 14mm socket on the torque wrench since they are 8mm bolts and start cranking away.  I'm then surprised to find that the socket starts slipping on the bolts when they get tight.  This strikes me as odd, but I don't actually PAUSE to ASSESS the SITUATION.

If I had, I would have seen that the bolts are in fact 13mm and not 14 like they usually are.  I was stripping them.

As I was tightening down the top left side bolt, there was a sudden CRACK and the wrench came off suddenly.  Apparently, I'd torqued the bolt enough that it ripped the bottom end rod in half.  Well, that's just great...

Though, if that rod was going to fail on torque, then it was always going to fail.  There's no way I could have under-torqued the bolts, somehow expecting the rod was weak.

Though I'm still not sure if the slipping socket had anything to do with it.  Did the slippage cause the wrench not to read the torque correctly which meant I was over-tightening?  I don't think so... but...

So definitely a major issue.  I think it's going to be a nightmare trying to remove the broken rod and replace it.  But I figure the engine should run with only 3 of 4 connecting rods???  Well, at least it that can't affect start up, can it?


After the shock of that wore off, I did the rear sprocket.  Pleased to find that in general, all the steps came back easily.  The job actually took a lot less time than I'd thought it would.

Run Ivy Run: Aftermarket woes

Freed the left throttle grip just because.  Took a lot of WD40 and elbow grease.

Found all 3 air boxes while also doing a big garage storage re-org.  Since the K&N didn''t fit the aftermarket carb, was hoping to get the stock box installed and just wait for the rubber hose to show up.

But the aftermarket carb can't fit the stock air box either!  Since the gas line sticks out the back, it totally interferes with the fit of the box.

New strategy:

First, setup one of the stock carbs plus the stock air box.  At least this maybe eliminates some unknowns by sticking with stock.

If that fails, or even in parallel, get the K&N RU-0100 offset version which should theoretically fit the aftermarket.


Carb and filter audit:

1. "$10" - has no covers but otherwise seems in good nick
2. Viola original - right cover is stuck on and there's an old filter bolted inside, so effectively useless until the cover is freed
3. "Number 3" - this came with 1 plastic cover, but the tab has broken off.  Otherwise in very good shape, so I stole 1 cover from the Viola box to make it complete.

Also, as of today, we have 3 used filters and a brand new repop one from 4-into-1.

Astrid: K&N

The K&N RU-0155 (38mm OD) was a perfect fit for the CM91 carb.  And more importantly, she actually ran with it.  But I actually started it with the normal airbox, let it warm up, then switched to the K&N.

What I discovered a few days later is that while she'll run with the K&N, she doesn't seem to be able to start with the K&N.  Must simply be too much air when the engine's cold (even choked).

Interesting...

Motor: K&N Pod Filter

Nice score with the K&N filter ($34 eBay).

Picked up an RU-0060 model with the 32mm inside flange diameter and it fit like a glove.  Might even be the same one Roxy uses?  Will need to check...

Spares: Unboxing Party

Haven't been in the garage for more than a month (life got in the way).

Unboxed the Early style airbox and intake.  Realized it's missing the right side cover and now I see why it's classified as unobtanium.

Unboxed another alt cover, this one to meant replace the "polished" one that seemed to nice to leave on the bike for now.

Unboxed Extra Sprocket Cover #2.

And finally, unboxed the old rusty cylinder meant to use for practicing honing.  But also discovered that the 51mm flex hone was a very tight fit in the 50mm standard cylinder.  You must have to really squeeze it in tight?  Guess we'll see....

Roxy: Annuals

Roxy got a new spark plug and I also cleaned and oiled the air filter.  Lubed the chain while I was at it, too.

 

Astrid: More Electrical 101

So I'm starting to understand the role of voltage in the overall system.  I'm pretty sure that when I was having issues starting recently, it was simply due to the fact that the battery wasn't putting out enough voltage to start the bike anymore.  I also clearly saw that just cranking it over and over again (causing spark but no start) is a sure way to drain any battery.

I feel like something about the rectifier wiring also affected the battery drain, but I have yet to prove that or understand it completely.

But I am sure that 5.9V is not enough to start the bike.  And on the flip side, 6.4V is indeed enough.  Not sure what the bare minimum is yet.

Also replaced Astrid's very perished rubber air hose with a 1 1/2" ID tube which I think is meant for a lawn water hose or something like that.

Roxy: Original Airbox

Took some time to open up and WD40 the airbox that came as spare parts for Roxy.  It's in excellent condition.  The only thing I'd replace is the plastic side cover on one side (the other side is chrome).

Even the air filter element was in good condition.