Time to build up top end:
I used a variety of techniques to measure squish and compression ratio:
I measure as low as 0.66 mm squish, and a compression ratio of 11.2:1 static. Squish is too low for a road bike really, and compression ratio i would like to see about 10:25 as per Wiseco piston design.
So i calculated i required an additional 0.7mm of clearance between the piston and the head, so i ordered some 1.5mm gasket paper to get the additional height from the original Cometic 0.7mm base gasket.
I then refitted the barrels and head onto the un-ringed pistons and re-did all my measurements with cams timed in properly. CR came out at 10.3:1 and squish at 1.40mm. Result!
Strip down again!
I then re-checked the piston rings for gap and fit and increased the gap on a few and sanded a radius onto both the edges of the ID of all the 2nd rings as it was a bit sharp. After ringing all the pistons and fitting 1 circlip and the gudgeon pin to each piston (1 and 2 on the rhs, 3 and 4 on the lhs) i fitted them to their respective homes:
And the reason for doing this
When i went to get my ring compressors out, there are only 3 to be found! The hazzards of moving house, grrrrr...
So the theory is:
Fit pistons into barrels individually easing each ring in at a time (there is a generous taper at the base of the Wiseco liners).
Fit my home made base gasket to bottom of barrels.
slide out gudgeon pins on 2 and 3 so the oil ring is just in the liner and the pin is out enough to clear the rod and can rest on the bottom of the liner.
Tip engine so it is resting on its front (so you dont have to fight gravity pulling the barrels down when you dont want them to go down)
Slide barrels on.
Rotate crank so rods 2 and 3 are at TDC.
Slide barrels down until they meet little end bore.
Slide Guineon pins into rods (can use a bar resting on top of the front head studs to support the conrods so they dont flop down and a phillips screw driver to locate the little end).
Fit the circlips in the pistons (can be a little fiddly as they are bastard tight anyway).
Slide pistons up bore by pushing down on barrels and rotating the crank.
Now push pistons 1 and 4 down so they meet the rods and repeat which is easier on the outer 2.
Applied RTV to base gasket in appropriate places, on barrels first, then block and pushed barrels down, head on quickly and torque down.
Next day, head off, head gaskets in and blue Hylomar applied around oil ways on both faces.
New Genuine cam chain tunnel seal and all new rubber blocks on the sprocket shafts.
Head on and torqued down for the last time.
I then re-checked the cam timing and adjusted slightly to get the 107/106 i wanted.
Wanted to get this all down so i have a record of what i have done and may be of interest to some??
Tried to re-use original cam end caps, half-moons or whatever
Either got pressed in or out on 2 of them, so ordered some TK Max ones off Ebay (seem good quality) and fitted them with no issues.
Slung the carbs on to get a feel for what its going to be like
Replaced comedy Athena tensioner gasket (thin and wrong shape) with home made one:
Gasket:1, Finger: Nil