KC
Just had a look at your page , you build nice bikes ( love the MP bike ) they all look good . I have the banana shaped chrome expansion chamber on mine but didn't notice a great deal of gain apart from noise . I made a small muffler out of some one inch pipe and gave it a little back pressure and got a nice bottom end from it . Do you have a preference as to which one works best ? Mine is a 66cc all stock except some better bolts with a 44 tooth rear . Have you tinkered with different carbys ? Are the internal hub gears any good ? If so what brand is holding up to the extra power put through it ? Cheers Rob