Engine Trouble Jerking

[SRPM]

So I had to replace the jug on my engine because my exhaust studs stripped out. So I put an old jug I had and rings that were used in that jug on the piston and put the jug on. The old jug ran nice I could take off nice and smooth all the way up to top speed. Now the new jug seems to run way more quietly and just jerks when I go to take off up to about 15mph then smooths out but seems weak I've tried almost all jet sizes I have and all clip settings. Also when idling it sounds like something is raddling or is lose, maybe rings?

 

[butre]

you can't use old rings in a new jug

 

[SRPM]

It's an old jug and rings that were previously used in it from an old engine

 

[crassius]

compare the 2 jugs to see if all ports are at same height & compare to see that distance from head gasket seat to base gasket seat are same - there are many different jugs out there