AT WHAT COLD CRANKING COMPRESSION DOES THE RIGHT GAS BECOME A PROBLEM

[GoFast.....]

Do you think maybe 195ccp and above

[Jeffd]

mine is at 190-192 CCP at 3400 feet and never a problem.  I can run on 85 octaine if I have to.  I was at sea level and never checked CCP but did not give me any problems and I could not make it ping even during 50 mph roll ons.  It never pinged on the dyno either.95" FT's, 26G, carb, stock ignition.  The only diff. I noticed at sea level is once at sea level my clutch started slipping and I have a VPC with stock spring.  Never once slipped prior to this or since  etc.

[Quick_2s]

It greatly depends on the variables, mine for instance is at 12.55:1 comp and 230 a hole and on pump 93 which is readily available all over my neck of the woods I'm not having issues winter or summer but CCP and dynamic compression due to cams I have learned is two vastly different things. My cam closes late so my dynamic is 10.39:1. I was worried I was detonating and just not hearing it but I just tore down the motor yesterday and the only problem I can see with it is that I'm still a little rich overall and more so on the front cylinder judging by heavier carbon buildup on that piston. I however from various conversations with "race" builders "THINK" that my problem lays more with lack of good spark due to the fact that it is a proven fact that spark is reduced by high compression and since to the best of my limited knowledge that there really isn't a hotter firing bolt on coil for the injected TC motors. So I think my solution probably lies in finding hotter plugs and the gap that makes them happy. Now all that being said I have not ran anything other than 93 in mine with the exception of once I got way out in the country and had to settle for 91 but again with no "noticeable" problem. I have since however kept a small bottle of octane boost stashed on the bike just in case I get caught out like that again. I think to get the answer your after you might want to clarify what the "right gas" is just for the sake of discussion. This is all just IMHO, I'm curious to see other more seasoned input.

[Hillside Motorcycle]

Have you changed the gear ratio of that bike?

[Quick_2s]

Which one?

[Hellraiser]

It greatly depends on the variables, mine for instance is at 12.55:1 comp and 230 a hole and on pump 93 which is readily available all over my neck of the woods I'm not having issues winter or summer but CCP and dynamic compression due to cams I have learned is two vastly different things. My cam closes late so my dynamic is 10.39:1. I was worried I was detonating and just not hearing it but I just tore down the motor yesterday and the only problem I can see with it is that I'm still a little rich overall and more so on the front cylinder judging by heavier carbon buildup on that piston. I however from various conversations with "race" builders "THINK" that my problem lays more with lack of good spark due to the fact that it is a proven fact that spark is reduced by high compression and since to the best of my limited knowledge that there really isn't a hotter firing bolt on coil for the injected TC motors. So I think my solution probably lies in finding hotter plugs and the gap that makes them happy. Now all that being said I have not ran anything other than 93 in mine with the exception of once I got way out in the country and had to settle for 91 but again with no "noticeable" problem. I have since however kept a small bottle of octane boost stashed on the bike just in case I get caught out like that again. I think to get the answer your after you might want to clarify what the "right gas" is just for the sake of discussion. This is all just IMHO, I'm curious to see other more seasoned input.

Previous build 220PSI per cylinder, 98 octane pinged like a mad cow in temperatures above 95F

[Quick_2s]

I rode mine all through the summer last year sometimes at 100+ temps, the only thing I can think of that may restrict mine from acting up in warm weather is the fact that it runs so cool, it is like pulling teeth to get the thing up "to" 200 on the dipstick, but I would think the combustion chamber temps ( where the pinging occurs ) would be more constant but I don't know.... that's above my head. Anyone want to chime in on that subject?

[GoFast.....]

I rode mine all through the summer last year sometimes at 100+ temps, the only thing I can think of that may restrict mine from acting up in warm weather is the fact that it runs so cool, it is like pulling teeth to get the thing up "to" 200 on the dipstick, but I would think the combustion chamber temps ( where the pinging occurs ) would be more constant but I don't know.... that's above my head. Anyone want to chime in on that subject?

How much compression were you running, compression builds heat

[Hillside Motorcycle]

Which one?

The overall gear ratio of the motorcycle.

[jsachs1]

Hellraiser,you made me roll off the couch,I was laughing so hard.About peed myself. 
John

[skyhook]

it depends a lot on the tune...i have a 110" dyna 200 ccp below sea level in new orleans...i keep the timing advanced as much as possible...if i get caught in stop and go, it will get really hot and ping...as long as i ride away from the city, no problems...just cant make myself retard the timing???!!!???

high comp just requires special care and feeding...if i wanted a bike for parade duty or cross country touring, it would be small cubes and 185 ccp max