This is the input shaft right-side bearing.  You can see the fretting on the inner race.  Also note the lengths Suzuki has gone to prevent the outer race from moving.  It has an anti-rotation pin plus a retainer plate.  I think the retainer plate’s primary mission is to lock the bearing axially.  It must handle thrust load off the helical primary gears.  This bearing was very difficult to jack out of the case.  It took a lot of force.  The right-side input bearing might be prone to spinning in the case.  Be careful with this bearing.  It also costs a fortune (about $75 bucks).

Right-side main bearing, no markings anywhere.  I get that I could simply measure the thing and go buy a 6207 bearing, but I need to know what clearance the designers intended (C1 through C5).  I think that’s important.  More to come.

I’m paranoid about balance shaft timing.  Recent reports from other forum members have shown ugly catastrophic failures caused by collisions between the rod and the balance shaft weight.  The only way that can happen is if the balance shaft timing gets out of whack.   For timing to shift, there must be a problem with the drive pin, drive key, or the cushioning springs.

Since my current problem manifested through noise & vibration, it stands to reason that I should be checking out the balance shaft system.

The balance shaft drive gear looks OK.  The teeth are not as smooth as I would like, but there isn’t anything ugly goin on.  The critical drive pin is tight and positioned where it’s supposed to be.   It hasn’t moved.

The balance shaft drive key is in good condition.  It’s tight and there are no signs of deformation or shearing.

Just look at the pits in the input gear.  A little more and I bet a tooth would have snapped off.

This shows the output gears for a 4-speed and a 5-speed.  The 4-speed top gear is on the left.  The 5-speed top gear is on the right.  Top gear on the 4-speed looks a lot beefier to me.

I’m currently running my spare engine that is set up with a 94mm flat-top Wiseco.  It’s running great and I intend to run it for a long time.  I’ve logged 3974 miles on it so far.  I want to do a long-term test on the flat-top piston.  I tore down the original 94mm flat-top engine when I started my Evolution of a HotRod project.  At that time, the 94mm flat-top had 2249 miles on it.  Add the additional 3974 miles from this current setup and the piston and rings have run 6223 miles.  So far so good.
 
When I reassembled the current engine, I just used the original 94mm flat-top and the cylinder it was running in.  I used the old rings over.  The Web 340b cam I had been running was pitted pretty bad, so I simply replaced it with my trusty old DR650 cam.  I left the heavy-duty RD springs and retainers alone (too lazy to change them).  The long-term test will provide an opportunity to see how the DR cam handles heavier springs.

So, I will continue to run the 94mm flat-top engine while I work on the Big Bore 4-Speed project.  I want to put 10,000 miles on it and then tear it down and report.  The focus will be the piston, rings, and cylinder to assess how the special piston holds up.

Regarding the transmission failure and the unusual bearing seats in the engine case, I solicit your input.

Have any of you seen the unusual fretting, tracking, chatter marks, dings, debris damage etc. that I show in my pictures of the main bearing bores?  If so, do you know what caused it?  How to fix it or prevent it?

Have any of you used Loctite 609 or 620?  What was your experience with the product?  Did you have to take the bearing out later and how hard was it to get out?

Have any of you experienced the tweaked crankshaft issue?  How did you deal with it?

Have any of you had a pitting problem with 5th gear?  What can you share?

Armen, throw me a bone.  What can you tell me about your Honda bearing failure?  Did the balls disintegrate?  Races spall?  Cages fall apart?  Outer races spin in the case?  How were the case bores?