Looking at your replies.i would suggest to change engine oil and observe it.
Llpw power is due to the gasket used. Metal gaskets come as a set of three sheets which decreases the compression ratio. Use fiber gaskets. They Are close to real gaskets.
Kia a carburettor bhi change kia ha?
Also male sure that openings of all pipes are inline. Ie carb to its haddi and hadi and head joints
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