The other night I finally got my build to run and I was able to go for and enjoy my first real ride on this bike. It ran AMAZINGLY...until suddenly it didn't. Right after the 2nd rebuild was completed it would turn over first pull. As the day went on it would take a couple more pulls, but it always would start. Then the next day it just wouldn't start at all. I have strong spark, compression, and fuel flow. I have checked my timing over and over again, checked/replaced so many plugs, checked all the seals, torqued down the head and every other part that could cause an air leak, I have inspected every millimeter of this engine inside and out and cannot find the problem. To my eye, on paper, it is a perfect build. But it absolutely refuses to start. Even shooting carb cleaner straight down the intake it won't turn over.
I have pestered all of my friends. Some say check the timing (checked and rechecked) some say it's too rich, some say it's too lean, there must be something I'm missing.
All I can get out of it is the occasional pop out of the exhaust at the end of every few pulls. I'm going mad and beginning to consider the problems may be supernatural in nature.
What could I possibly be missing? What could cause this bike to run perfectly and then suddenly not at all?
Set up the one and only time it ran correctly (has not changed):
Treats 70cc kit
16.16 Sha (77 jet)
Proma circuit pipe
B7hs ngk plug
Please help me. I've been working on this for months with nothing but problems, and I finally get it to run like I had dreamed of it and it just stops working with no explanation.