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Thumper · 12-28-2022, 11:13 AM

Thanks Pete. That is a nice, complete comparison of 4stroke/2stroke engines.

That video shows the Yamaha power valve engineering to vary exhaust port size. The Loncin 249cc engine has a power valve. You can see the cam and control cabling on the port side of the engine. These cables are adjustable, so this means they can be tuned, but also can go OUT of adjustment! The Loncin uses the Yamaha power valve design, and there are videos on adjusting, or replacing them. Adjustment turns out to be easy.

The same exact Loncin engine is used in the KAYO. Piston/ring/gasket kits are available via AliExpress under $30. Cool!

12-28-2022, 11:13 AM	#6
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,423	Thanks Pete. That is a nice, complete comparison of 4stroke/2stroke engines. That video shows the Yamaha power valve engineering to vary exhaust port size. The Loncin 249cc engine has a power valve. You can see the cam and control cabling on the port side of the engine. These cables are adjustable, so this means they can be tuned, but also can go OUT of adjustment! The Loncin uses the Yamaha power valve design, and there are videos on adjusting, or replacing them. Adjustment turns out to be easy. The same exact Loncin engine is used in the KAYO. Piston/ring/gasket kits are available via AliExpress under $30. Cool! Last edited by Thumper; 12-28-2022 at 02:49 PM.
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