Great tip Ed, your years of experience are priceless.
I'm adding the CA77 tip to my list of ideas for when I rebuild my CL77 top end.
Let me know next time you're in New Orleans and I'll cook us up some ribs in my CL grill.
Thanks.
are kenig hi comp.pistons any good ??I checked out a CA piston on ebay and sure as LM said, it's like a CB350 piston. Are the CA and CB combustion chambers the same with that recess around the edge?
Makes me wonder why Honda left that piston in the CA and lowered the outer ring on the higher revving CB. Maybe it touched the head at higher revs. My handbook says that the Dream has lower compression than a CB, so one of these days I'll have to get a CA piston and head and measure the volumes and maybe that will shed some light on what's going on there. LM, are CA and CB pistons the same height from the pin to the top of the crown?
I've installed several of the CA pistons in CB/CL engines and they ran/run well.
Both of the heads have the the same combustion edges but the CA has a deeper chamber and valves which allows for more volume there. I checked the reason for the difference in combustion several years back. For many years if ya asked anyone (even the experts) why the CA had less compression than the CB/CL the reply was "It's the Pistons". Well one day as I was rebuilding a engine and was looking at both style pistons on my bench I decided to get to the reason for the difference. To my surprise I found they both have the same measurement from wrist pin to dome. I installed both type in a cylinder assy. I had and CC'ed and found the CA type took less water than the CB/CL type. OK NOW THE CA PISTON HAS LESS VOLUME SO HIGHER COMPRESSION. Next I CC'ed both type heads and found the CA head took many CC more than the CB/CL. OK SO THE CA HAS MORE VOLUME SO "THERE IS WHERE THE LOWER COMPRESSION COMES FROM". I had a supplier with some good AM .25 and .75 CA pistons and I bought all I could. When I rebuild or sell these type pistons I always offer the CA types as they work well and I can ask for less $$$ for them. .............lm
FOOD FOR THOUGHT
My HONDA Little Red Book shows compression for each Design and at the top of the page 72/77. Would ya believe the compression given for ALL engines is """"""""150PSI"""""""". Figure that!!!!!!!. .....lm
Honda appear to not only change the specifications, but also change what they say. My Shop manual dated 1960 says Compression pressure C77 8.5 Kg/Cm2 (120.87 psi)
and for the CB77 they say 10.5 kg/cm2 (149.31psi). That copy does not quote a CR for the Dream but says that the CB was 9.3 - 9.7 The Dream 150 PSI number is quite possibly an error in the book. LM's measurements seem to support that the Dream CR was lower overall CR and that it was because the combustion chamber was larger.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
