The only thing I found of any significance was the o-ring on the push piece.  I could tell as soon as I went to pull the release plate and push piece that it was loose.  The push piece came out of the input shaft with zero resistance.  It essentially fell out.  My experience with this o-ring has been that it fits super-tight into the input shaft.  Visual inspection revealed a flat o-ring.  It was worn out.  A leak here might reduce oil pressure at the input shaft spacer, clutch basket bushings, and thrust washer.

What’s causing the rattling noise?  While I was under the clutch cover, I checked torque on the primary drive nut and the balance shaft bolt.  They were right up to spec.  The only easy thing left to check was the flywheel.  I pulled off the alternator cover, alternator rotor, and the starter drive.  The flywheel looked tight, and I couldn’t rotate the nut with my fingers.

The splines looked good.

If you recall, I switched to the stock flywheel just to be safe.  I had some weird stuff goin on with the bearing bores in my other engine.  There was a remote possibility that the mini flywheel might have had something to do with mysterious bearing bore anomalies.

After lots of research and thorough inspection, I haven’t been able to establish any correlation between my messed-up bearing bores in the other engine and the 3-inch flywheel.   I decided to install the 3-incher on this engine and see how things shake out.  So, on went the mini wheel.  It got torqued to 110 ft-lbs.  You need the correct tools to do this job.  No more rattle wrenches for me.  When I start this thing up, I will know immediately if the mysterious rattle was the loose flywheel.

Time to put it back together and see if I corrected the loud metallic rattle.  Since I had the fuel tank off, I decided to lubricate my speedo cable.  I used a very light coat of moly lube.  Anyone have any thoughts on that?

It fired right up.  I immediately knew that the flywheel repair was successful.  The loud metallic rattle was gone.  The engine now sounds normal, quiet for a Savage.

The clutch squeal is gone, and engagement is smooth and progressive.  What the heck fixed that?  I’ve put about 300 miles on it since completing the service.  It’s still working perfect.  Might have been the push piece o-ring.  If it acts up again, I will focus on the input shaft spacer, thrust washers, and push piece o-ring.  It has a generic nitrile o-ring in it now.  I need to order a few of the genuine Suzuki o-rings.

I got so worked up over the noise and the clutch that I never inspected the intake port epoxy.  I’ll check that next time.

The PWK carb is still working great.  I did finally have to adjust it.  The light flywheel brought the idle down to about 1000 rpm.  I like it about 1300 to 1400, so I had to raise it up a bit.  First time I’ve touched the carb in a very long time.

The old S40 got a new set of rubber and a new front brake rotor.  Ready for safety check.  Amazing how much better it handles with new tires.  I installed Dunlop 404s.  Those were a $itch to mount.  Way harder than the stock IRCs.  It’s difficult to get tires out here.  Shipping is through the roof.  I don’t like the aspect ratio on the rear Dunlop, it’s too tall.  But I must admit, it handles nice with these new tires.  Cruising rpm is a little more relaxed too, but acceleration is a bit slower.  What ya gonna do?  Play the hand your dealt.

My plan was to tear the engine down at the 10,000-mile mark, but the Big Bore 4-speed isn’t ready yet, and this 94mm Flat-Top is runnin sweet.  I’m gonna keep runnin it for a while.  I have to admit, with this one runnin so good I’ve lost motivation to work on the other one.  I must focus, get the big one finished.

See you at 39,283 miles.  

Thanks for the detailed reporting!
So, a million years ago I built a hotrod Bultaco that ran in 250 and 350 GP in AHRMA. The guy who owned the bike (my dear friend David) had some quirks. One of which was the insistence on running the stock, external rotor magneto. Insane. As the revs and HP went up, this rotating boat anchor was more and more of a liability.
So, one year at Daytona, David gets towed back in with a dead motor.
I pull off the left cover, and the magneto and the end of the crank fall out. The quick transitions from full on to full off were too much for the crank.
As it was, Kevin Cameron (tech writer extraordinaire) was walking by and looked over. Before I could even ask what he thought, he said “What do you think?!?!”.
So, I built a new crank, and we went to an internal rotor magneto.
Problem solved.
So, yeah, I like light flywheels  when you tweak the bikes.

I hear what you are sayin Justin.  Don't look a gift horse in the mouth.  Time will tell.

Armen, that old Taco sounds like it was killer.  You've mentioned it a time or two.  I'd really love to see it.  There was a simplicity in those old Spanish hotrods that made them extra special.  There were only a few out here in the late sixties and early seventies.  Can you post some pics in the Cafe, or maybe email a few to me?

I always had a lot of respect for KC.  His articles in the old motorcycling publications were the best.  Always chock full of the theory behind the designs, loads of intricate and useful nuts & bolts meat & potatoes.  Cool that you got to hang with a guy like that.

I just don't get this flywheel on the LS.  I've converted several dirt bikes to internal rotor mags.  The rev factor was always a major change.  The little ringdings would rev instantly when you snapped the throttle.  My Harley Evolution dragster was a totally different animal when I removed the charging system and went to total loss.  Like night & day, whack the twist grip, instant revs.  This LS..... take six pounds off the wheel and you can't even tell the difference.  Crazy.

Regarding snapping off the crank, again I am totally bamboozled.  Look at the drive side vs the alternator side.  The alternator side is twice as robust, way more beef.  The left side also has that big, beefy roller bearing vs the whimpy ball bearing on the drive side.  But the drive side transmits all the torque, and also has to turn the cam.  Bizarre to say the least.

If the alternator rotor and flywheel require that much shaft, there must be an inordinate amount of inertia to overcome, yet I can lob six pounds of dead weight off and nothing seems to change.

You still chummy with KC.  Can you ask him?

39,357 miles.  Time for the next service.