It's a shame that the EDPM doesn't tolerate the fuel.  I would be careful with the elbow also.  My ABS elbow was in service for a very long time, and then it just failed.  I was surprised.  A big chunk of plastic running through the intake valves could have been bad.

I tested the new PVC elbow for about one week, but I still don't trust it completely.  I inspect it every time I do a service on the bike.  It's been in there about 2.5 years now.  So far so good.

This failure occurred with no warning.  Seemed like one day it was good and the next it had failed completely.  And after I removed the elbow, it continued to deteriorate on the workbench.

Must have been handicapped when it was born.
They depart this life early for sure.

The first step was to measure deck height properly, and the vernier caliper said piston is 0.8mm below cylinder top surface.

I am no expert in terminology, but does that mean deck height of -0.8mm?

This is with an uncompressed base gasket.

Then it is just a matter of attaching the cylinder head to cylinder, torque the bolts to spec, and turn the engine back and forth over TDC a couple of times, disassemble again and see what gives. It was obvious to me that the solder had been compressed a lot, because the piston did not pass ovet TDC without a bit of effort. not massive, just enough to indicate that the solder had been flattened thoroughly.

Therefore I was not surprised when I saw this:

First set tappets to zero clearance, to get valves as close as possible to the piston, then rotate engine past TDC a couple times.  

After that, tear the engine down to the piston top and check the clay for interference.

Things are looking safe and sound, and it only took around 2 hours in total, hours well spent for certainty instead of guessing.

I only have to check the valve springs for pressure and reverse a couple of them, then the engine can go together for good.

Thanks for all the pics Finn.  Looks like you have plenty of clearance between the valves and piston, and the quench clearance looks good too.

I'm not sure how you arrived at the 0.8 mm negative deck and then ended up with .044" quench clearance.  The head gasket should be .028" and when combined with .031" (0.8 mm) negative deck you end up with .059 quench, but the real test is the lead wire.  That's the real deal.  I agree that it should end up a little less than .044" given how much you crushed the lead (you can almost see through it).

Your valve-to-piston clearance looks to be more than what I had.  I'm not sure why, but Lancer previously mentioned that I have an early prototype of the 94mm flat top piston.  I believe that Wiseco made some changes to the valve reliefs on the 97mm flat top, but I don't know if they did something similar to the 94mm.  Hey Lancer, if you are following this, did Wiseco increase the reliefs on the 94mm also?

I must apologize, I have forgotten what country you reside.  However, if you want an easy fix for your elbow and air boot problem, you can purchase those items off eBay, and they ship to both the Netherlands and Denmark.  The street elbow (spigot x hub) requires a short section of 2" pipe to set it up with a spigot fit on both ends.  If you can find a spigot x spigot would probably be better, but I can assure you the spigot x hub fits perfectly.  The street elbow has a larger radius so it will flow much better than a standard 90 degree elbow, and the required length for the air boot is reduced significantly.  Hopefully these two links will be helpful.

Elbow

[url]2" PVC 90 Degree Street Elbow Fitting In Wall Central Vacuum Pipe Suction Tube | eBay[/url]


Rubber Coupling

[url]Flexible PVC Rubber Coupling Connectors with Stainless Steel Clamps 1"in-8"in | eBay[/url]

Hmmm, still not active.  Let's try another way.

https://www.ebay.com/itm/235264292538?chn=ps&norover=1&mkevt=1&mkrid=711-1669...


https://www.ebay.com/itm/224480913284?chn=ps&var=523263414908&_trkparms=ispr%...