SlowMoe

Not running a spacer plate. Running 21cc stroker domes with 150 psi compression. Squish at .048" Sent from my iPhone using Tapatalk

We figured my UCCR is about 12.5-13.0:1. I will pull back timing and watch for signs of detonation and if need be mix in some race fuel Sent from my iPhone using Tapatalk

How would your math look? 55.5mm bore 58mm stroke 21cc dome And at what UCCR is pump gas no longer safe? Sent from my iPhone using Tapatalk

It's cool. I've built like 5 motors from scratch but it just didn't feel right this time Sent from my iPhone using Tapatalk

^this is what the builder sent me Sent from my iPhone using Tapatalk

65.5x65.5x58x3.1416¿4000= 195.4346163+21 then divide the total of that by 21 which is the cc of the dome equals 10.30 compression which is safe for pump gas Sent from my iPhone using Tapatalk

The crank wasn't fully assembled with all the gears and stuff and I just didn't feel comfortable for some reason Sent from my iPhone using Tapatalk

Brandon: What size domes do recommend for pump gas? Recommended user: What kind of measuring device is typically used to measure the amount of oil poured on top of the piston, and you stop at the spark plug hole, correct? Sleeper06: What trapped volume and displacement did you use in your calculations? I'm just confused, as my builder is not a newb. Has clients bikes in his shop from two states over and assures me my bike is safe to run on pump gas. If indeed I have a problem on my hands I would rather just buy new domes than be stuck running race gas. FWIW I ran the piss out of it today at the dunes on pump gas with no issues. Mainly because I have faith in my builder. However you guys have me curious and I would like the peace of mind if doing the displacement calculations myself and coming to my own conclusion before moving any further. Sent from my iPhone using Tapatalk

So you're saying trapped volume will be significantly less than 21cc? Sent from my iPhone using Tapatalk

That was a typo I meant 221cc/21cc = 10.52:1 Sent from my iPhone using Tapatalk

The builder has told be more than once that 21cc domes are good for pump gas. I am doing 200cc / 21cc = 10.5:1. 10.5:1 is pump gas safe right? Sent from my iPhone using Tapatalk

None of what you just said makes any sense lol Sent from my iPhone using Tapatalk

And what is the UCCR formula? Is it cylinder displacement+ dome size/ dome size? Sent from my iPhone using Tapatalk

So for 14:1 you recommend 100% race fuel? Sent from my iPhone using Tapatalk

Well, is that race gas territory or what? Sent from my iPhone using Tapatalk