Vader 150 -> 250. - Page 2

delzy · 11-07-2024, 10:24 AM

I bought an OHC engine off Amazon for my RPS Condor. I also bought one of those 4-valve 23hp engines from ALIbaba and they simply stole my money.. $550 out the window. Oh, well. I guess that's what I get for trying to trade directly with the Chinese. I have yet to start the conversion, but my original CG150 is running great with just a few mods. The winter project awaits.

ProDigit · Yesterday, 10:25 PM

Since I forgot to record my bike's odo before I swapped the 150cc engine to the cg250, I'd guess there is now roughly 500+ miles on the new engine.
I just did my oil change.
Last time I did the oil change, I tightened the valves, both intake and exhaust.
The bike lately started quite hard cold, and I heard the valves ticking.

After opening, I found that the intake valve was ever so slightly loose, enough to give a faint ticking sound when riding.
The engine power seemed to also have dropped somewhat gradually over time, making it difficult for the engine to push the bike past 5.3k rpm.

The exhaust valve was still pretty tight, so I tightened the intake valve once again on a hot engine.
It now starts right up again, and the ticking sound is nearly gone.

Just showing that the intake and exhaust valves need to be butt clenching tight at zero miles, and tightened again when they make sound.

Performance also increased noticeably, after tightening the intake valve.
I've mentioned it before, but the cg 250 engine suffers from air starvation at higher rpms. Tightening the intake valve helps tremendously. If only someone could make a camshaft where the lines are a fraction wider. It might make the bike run slightly worse at idle, but should do wonders on increasing HP at the higher rev range.

The second best thing is getting valve springs that are a bit weaker. They could keep the valves open a bit longer.

I don't know enough about this, but it may be possible to use a vice grip to tension the valves, and heat them up with a propane burner, then let them cool. Should reduce tension, by a bit; but I haven't tried yet.You could also screw up the engine if the valves stay open too long and hit the piston.

It'll be interesting to see who can find a way to get more HP out of these engines for cheap.

11-07-2024, 10:24 AM	#16
delzy Join Date: Jan 2024 Posts: 36	I bought an OHC engine off Amazon for my RPS Condor. I also bought one of those 4-valve 23hp engines from ALIbaba and they simply stole my money.. $550 out the window. Oh, well. I guess that's what I get for trying to trade directly with the Chinese. I have yet to start the conversion, but my original CG150 is running great with just a few mods. The winter project awaits. __________________ My ongoing build: https://www.chinariders.net/showthread.php?t=33747
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Yesterday, 10:25 PM	#17
ProDigit Join Date: Aug 2013 Location: FL Posts: 372	Since I forgot to record my bike's odo before I swapped the 150cc engine to the cg250, I'd guess there is now roughly 500+ miles on the new engine. I just did my oil change. Last time I did the oil change, I tightened the valves, both intake and exhaust. The bike lately started quite hard cold, and I heard the valves ticking. After opening, I found that the intake valve was ever so slightly loose, enough to give a faint ticking sound when riding. The engine power seemed to also have dropped somewhat gradually over time, making it difficult for the engine to push the bike past 5.3k rpm. The exhaust valve was still pretty tight, so I tightened the intake valve once again on a hot engine. It now starts right up again, and the ticking sound is nearly gone. Just showing that the intake and exhaust valves need to be butt clenching tight at zero miles, and tightened again when they make sound. Performance also increased noticeably, after tightening the intake valve. I've mentioned it before, but the cg 250 engine suffers from air starvation at higher rpms. Tightening the intake valve helps tremendously. If only someone could make a camshaft where the lines are a fraction wider. It might make the bike run slightly worse at idle, but should do wonders on increasing HP at the higher rev range. The second best thing is getting valve springs that are a bit weaker. They could keep the valves open a bit longer. I don't know enough about this, but it may be possible to use a vice grip to tension the valves, and heat them up with a propane burner, then let them cool. Should reduce tension, by a bit; but I haven't tried yet.You could also screw up the engine if the valves stay open too long and hit the piston. It'll be interesting to see who can find a way to get more HP out of these engines for cheap. __________________
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