Atc90 compressiOn ? And timing ?

[vartiak15]

I am trying to get my modded 90 motor running but it doesn't seem to haVe A lot of compression for having a rocky 55mm, roller cam, sl90 tranny, 125 carb, home built exhaust, heavy duty valve sprins and more. Is there a minimum comp I need to have.???

Now for timing does it have to be perfect.? And when lining up the marks they match one on one rotation them it skips one then goes back right? Any tips for lining up timing?

[vartiak15]

Anyone..... Where all the 90 guys at