reducing

Good day all I need sounding board for my thoughts on how to reduce top end speed. Recently purchased what I believe is a doodle bug, and with the current gear and engine set up the online calculators show me a top speed of 31mph (stock tires, 1:5 ratio and 3600 rpms). Way too quick for my 8...

Hey, I just finished building an engine for my new style doodlebug. I am really pleased with the speed but the thing vibrates so much at and kind of speed that it is borderline unusable. Right now, the motor has a 14cc head, gx390 carb, rev s2 flywheel, 265m cam, billet rod, 18lbs springs, and...

I haven't had to deal with this problem yet because I am STILL putting my bike together but I read on here once that cutting a rubber muddflap to size and installing it under your engine helps. I'm just wondering if anyone has done this and what kind of results they have seen? Does it actually...