Ivy: Cylinder and Piston Swap

Swapped Ivy's cylinder and piston for the ones just removed from Roxy.  Straight forward swap, but no joy.  Still smoking.  Which was somewhat to be expected given they were smoking coming off of Roxy, too.

Flipped the horn right side up so it wouldn't hit the fender, though... damage done.

Big Bore!

Got the Big Bore kit back from DRATV (Beatrice Cycle).  Bored out to 53.50mm (leaving that extra .5mm for the future. 

Kit comes with the 5 piece ring set, wrist pin & circlips, and also a thicker copper gasket you need to use because the piston's a bit taller.

I also got the racing camshaft.

Does this go into Red, or do we build a whole new bike around it?

Roxy: Bore Size Reveal

So turns out Roxy's cylinder is a standard 50mm. 

So why then did she always feel like she had a little more grunt?  She seemed both heavier and torquier than Ivy.  Or has it just been my imagination this whole time?

And why the breather tube on the tappet cover (as if it needed to bleed off loads of extra pressure)?

Red: Process of Elimination

Swapped in the "Flexhone Practice Jug #2" cylinder hoping that it would resolve the smoking issue, despite the fact that the walls were only marginally better than the original.

At first, there seemed like much less smoke (though it was still definitely smoking).  But then taking it around the block a few times showed that there was literally no change.  If anything, it was even a bit worse.

Summer Session #2: Jug Swap

Swapped out the jugs on the model engine.  Installed the new black media-blasted one from eBay for the orange +.25 one which could be a candidate for Red.

Red: Engine Investigation

Had the day off and decided to audit all the jugs and cylinder heads, starting by pulling the "Mystery" one from Astrid.  Simply can't remember its origin.  I know that I swapped whatever was on Viola/Ivy for the Astrid top end back when we were getting her running, but was that the original Viola top?  I have another cylinder head marked "Viola", but maybe that came as a spare part?

Regardless, I pulled that jug and head from Astrid and brought that up for carpet work along with the "Viola" one.

Stated by inspecting the valves, which I did on the Viola one (everything was within wear limit), but found the Mystery rocker cover screws were frozen and stripped.  Again, not sure why that never got addressed.

Tried to mate the Viola head on the Mystery jug and came to the realization that they are two completely different models.

The Mystery jug has a 68mm surface with no groove in it.  While the Viola has a 65mm cylinder surface.

Are these really 2 different S90 jugs?  I need to lookup the Yahoo discussions again.  I think the Viola 65mm is definitely stock S90 so if anything is different, it's the Mystery one.