I have had a couple of Zenoah manifolds fail, the brass insert pulls through the plastic and the intake leaks, I ruined one engine this way. This is what I do to the CY to make it "better". I did not port the inside yet, but this is what I do to increase the sealing surface
What it looks like when I start.
I screw a couple bolts into the threads so I can start a tap later
Fill er up with the real JB, the stuff that sets over 24 hours.
I remove the bolts once the JB sets and drill the holes through and tap the JB weld.
THen I sand it all flat on some 320 them 660 wet/dry.
What it looks like when I start.
I screw a couple bolts into the threads so I can start a tap later
Fill er up with the real JB, the stuff that sets over 24 hours.
I remove the bolts once the JB sets and drill the holes through and tap the JB weld.
THen I sand it all flat on some 320 them 660 wet/dry.