Billet cylinder head design for cg 125. ..HELP..
- Thread starter hidrojen
- Start date
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Seems like it would be easier to cast that piece, due to the fins and the small webs between the fins.
Here is a example of someone in California who cast their own motorcycle racing engine parts, and successfully raced with them.
https://www.homemodelenginemachinis...se-casting-motorcycle-racing-cylinders.35502/
.
Here is a example of someone in California who cast their own motorcycle racing engine parts, and successfully raced with them.
https://www.homemodelenginemachinis...se-casting-motorcycle-racing-cylinders.35502/
.
Why would you think the original head design would not 'withstand high revs'?
If the engine RPM is too high, I would expect the rod to be the first thing to fail.
Higher RPM may require higher valve spring preload, but that would not impact on the head design unless it became so ridiculously high that it deformed the ports.
If the engine RPM is too high, I would expect the rod to be the first thing to fail.
Higher RPM may require higher valve spring preload, but that would not impact on the head design unless it became so ridiculously high that it deformed the ports.
The material of the original cylinder head is bad, anyway, when a performance camshaft is installed, the engine goes to high speeds and produces excessive power. When the original valve springs are not strengthened, valve float occurs. This damages not only the cylinder but also the cylinder head, so I was planning to remove the cylinder head from the CNC machine with a different material.
If you have an original Honda engine, the material of the head should be good for some heavy use.
The CB125 (overhead cam) heads may be limited, but the CG125 is notoriously bulletproof.
The rest of the engine will not hold together at such high RPM as would require valve springs so strong that they would damage the original head.
Valve bounce will damage the valves and the valve seats, but the engine will stop before it damages the head.
I have been involved with drag racing engines which use original cast alloy heads from the 1950s, running with alcohol fuel and nitromethane. It's not easy to damage the head casting!
I suggest using the original head until you break it - then see what broke and think about what to improve.
The CB125 (overhead cam) heads may be limited, but the CG125 is notoriously bulletproof.
The rest of the engine will not hold together at such high RPM as would require valve springs so strong that they would damage the original head.
Valve bounce will damage the valves and the valve seats, but the engine will stop before it damages the head.
I have been involved with drag racing engines which use original cast alloy heads from the 1950s, running with alcohol fuel and nitromethane. It's not easy to damage the head casting!
I suggest using the original head until you break it - then see what broke and think about what to improve.
When you install a large piston in the engine, it starts burning oil because it cannot completely scrape the oil off the cylinder surface. How can this be solved? in addition, the engine scratches the surface by sticking to the cylinder piston at high rpm, so how to solve this?
Reduce the tangential pre-load on the piston ring. as it helps a bit. Reduce the side clearance of ring in the piston groove, which helps minimise the gas pressure behind the piston ring, providing the ring does not seize in the groove.
Use Molybdenum in the oil - After running-in! It helps prevent scuffing.
Use a finer grade of stone when honing bores, 1000 grit instead of 600 grit, or whatever is one grit finer than your current stone grade.
Increase cylinder cooling, if you can.
I heard of water spray onto the cylinder being used by a bloke racing an air cooled single, supposedly to help keep the Standard finning cool... to avoid it seizing with the high compression piston and larger intake and carb used for racing, with well advanced ignition. But hearsay isn't always reliable...
K2
Use Molybdenum in the oil - After running-in! It helps prevent scuffing.
Use a finer grade of stone when honing bores, 1000 grit instead of 600 grit, or whatever is one grit finer than your current stone grade.
Increase cylinder cooling, if you can.
I heard of water spray onto the cylinder being used by a bloke racing an air cooled single, supposedly to help keep the Standard finning cool... to avoid it seizing with the high compression piston and larger intake and carb used for racing, with well advanced ignition. But hearsay isn't always reliable...
K2
