The only way to test this with any degree of certainty.
Fit the water dome. I just fit them with silicone sealer. no more problems.
Blank off one hose
Pressurise the other if you can to about 20psi
Immerse in a bucket of water
Watch for the bubbles
My guess is a leak from the water jacket into the exhaust chamber
Because it is inclined forward, it will run into the exhaust rather than back into the crankcase.
If you can locate the position, you might be able to block it up with some thin epoxy
Best to clean and dry block,
Put some small stones or ball bearings in the water jacket
Shake it to try and clean soft calcium residues
Put some cleaning solvent in
Pressurise to blow it through the leakage cracks
Empty and dry
Put in some thin epoxy and incline to get it to run to area where the crack is. Slow set is best if you can get it, as you can put the top on and pressurise the sealant to try and get it to go into the cracks.;
Pray
If you could get thin silicone sealant, this might be good, as Hertel have stopped making “Slow set Plastic Padding” in Finland and I have not found an alternative yet.
No use getting worried too quickly, but the pressure test, similar to finding a puncture in a tyre is the best test.
If you do not have a compressor, cut up an old bicycle inner tube.
Fix one end to one of the water pipes. Block off the other water pipe.
Block off the open end of the cut inner tube
Blow up the inner tube and the elasticity of the tube will exert the air test pressure you require.
Let us know what you find
Kind Regards
Roger Moss
