Yt60 porting and design 4 powah (safely) DUI bike edition

So last year I adapted a yt60 jug to them motorized bike kits. Made a reed valve bolt to the case, added a third case case transfer, made a bastard pipe out of scrap metal and what ever pipes I had lying around. The thing only hit 38 mph but it had great torque and I was even able to make good money doing food delivery with it. I eventually cold seized it unfortunately cause I was a scrub who didnt know better about letting cast iron cylinders warm up. A bunch of reading, experience, and builds later now I really want to revisit this build and max it out. The cylinder kits can be had for 40-60 dollars so fuck it ( mph per dollar duh). Some measuring and math later I figure to raise the exhuast to increase the exhuast timing and blowdown to 174 degrees EO and 25 degrees blowdown. I even calculated a tuned pipe for this cylinder with a pipe calculator online. My only question really is should I mess with the transfer ports? They seem to be angled towards the rear of the cylinder with the side transfers and the third transfers roof angle to the spark plug. My only thought is the floor of the third transfers dont really angle up like the roof where they could be shooting air and fuel out the exhaust.

yt60 pipe final.png

Re: Yt60 porting and design 4 powah (safely) DUI bike edition

I like this project.

I recommend comparing stats to other exhaust pipe calculators and seeing what they spit out, there is some variance.

Also, I’ve never heard of cold seizing, will be googling that.

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