SOHC.co.uk Forums > CB500/550
CB125 Pistons/rings suitable for 500/4 ?
Trigger:
--- Quote from: Oddjob on August 03, 2016, 02:48:37 PM ---What about a single pot then Graham, like say the CB100 or CB125. All areas are cooled but the front 2 would get more cooling, would this result in a double egg shape?
--- End quote ---
All piston's are oval shape when cold, with the narrowest area in the area of the gudgeon pin as this area is the hottest and expands more during running. You will always get uneven wear with a object that is not round moving that fast and hot in a round bore. All this with outside temperatures cooling it unevenly leads to uneven shaped bores.
Kawasaki got it all wrong with the KH 250 as the piston to bore clearance was the same on all three cylinders. This caused the centre pot to over heat and seize due to uneven heat displacement. Give the centre pot a tad more clearance and the problem was resolved.
AshimotoK0:
--- Quote from: Trigger on August 04, 2016, 08:04:28 AM ---
--- Quote from: Oddjob on August 03, 2016, 02:48:37 PM ---What about a single pot then Graham, like say the CB100 or CB125. All areas are cooled but the front 2 would get more cooling, would this result in a double egg shape?
--- End quote ---
All piston's are oval shape when cold, with the narrowest area in the area of the gudgeon pin as this area is the hottest and expands more during running. You will always get uneven wear with a object that is not round moving that fast and hot in a round bore. All this with outside temperatures cooling it unevenly leads to uneven shaped bores.
Kawasaki got it all wrong with the KH 250 as the piston to bore clearance was the same on all three cylinders. This caused the centre pot to over heat and seize due to uneven heat displacement. Give the centre pot a tad more clearance and the problem was resolved.
--- End quote ---
Any comments on the two types of oil 'spring' in my piccies from you Graham? Think I am going to use the CB125T rings on my 500K0 (3-piece oil control ring version).
Trigger:
I always favour the 3 piece over the 1 piece oil ring. Years ago I fitted 4 piece oil rings (Not to Honda's) but, don't see them around any more.
AshimotoK0:
--- Quote from: Trigger on August 04, 2016, 09:09:22 PM ---I always favour the 3 piece over the 1 piece oil ring. Years ago I fitted 4 piece oil rings (Not to Honda's) but, don't see them around any more.
--- End quote ---
What I meant tho' Graham is given that I accept that I am going to use 3-piece ring sets, the CB125A ring sets have a slightly different 'rail' section in the centre portion of their 3-ring oil control ring set ( see pics above).
Trigger:
That control ring is STD on a lot of 80's Honda's, including the CX. And I would not like to comment unless I have measured it to the piston.
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