i run 11 to 1 on pump gas with no probs....done it with two builds, the 98" with 615/585 cams(one of the best and quietest cams IMO) and now on my 117 with Woods 9b's....my R&R cast heads allow for it and i rarely use the comp releases

 

10.:1. Woods 408B cams. Buckets of TQ.

 

and i might add that i make 129hp/139 ftlbs...with well over 100ftlbs at 2500rpm....dont hodpodge a build...talk to one of the builders and buy a proven kit...like GMR, Headquarters, Hillside, or KingofCubes...i've seen several WildThings builds that rocked as well...dont settle for a lazy big bore when you can have an angry monster for the same money....dont let anyone tell you "no, no, no", as they most probly got their info from the koolaid stand at the dealership on saturday morning

 

this is some funny chit "as they most probly got their info from the koolaid stand at the dealership on saturday morning"

 

Ok, build in question was a 10.5 to 1 pistons, originally used Woods TW6 cams=lots of detonation EVEN with octane booster. Swapped cams to an Andrews TW60, lost a bunch of low end TQ, but still over 100/100. Detonation was better, but had the fuel bumped to about 12.9/1 which only resulted in about 30 mpg. Obviously, this bike was not built for fuel mileage, but 30 mpg sucks. I went back in and used a 9.25 to 1 piston and changed to Andrews TW54 cams. ZERO detonation, 38 mpg and 98/101 on the wheel.

Oh, did I mention the overheating issues with 10.5 compression? 3 Oil coolers, parade fan, and about 3 red lights in the summer heat and you were in heat management. My point is that dropping the compression to a manageable level does not greatly affect your peak numbers. To put it another way, why would you risk all the aggravation of high compression when the same performance can be had at a lower compression?

 

proof positive to buy a proven kit....sounds like your combo wasnt happy

 

Not to start an argument, but if I did not hate to type so much, I could cite a dozen or so builds that were in the neighborhood of 10.5 compression that had similar and worse problems. If it works for you, great! It did not work for me, or several of my riding buddies, and we have all found that compression aint really all that necessary. I go all over the place on my bike, and have been in areas that do not even offer premium fuel. I will never have a high compression build again....

 

get a proven kit -- I have had two HQs Motor Kits a 103 and now HQs 107 both at 10.5. I have had none of the problems you mentioned even using 87 octane a couple of weeks ago (that is all we had in Atlanta).

I don't know much about motors but the first thing I learned and understood was to get parts that compliment each other.

putting a bunch of parts together that look good on paper may not work well together.

I have used HQs stuff twice now -- to tune of a lot of $$$ (motor work aint cheap) there stuff works for me.

 

95" - 10.5 Wiseco pistons, 577 Redshift geardrive, Baisley head mod, Feuling pump, roller rockers and a PCIII. NO pinging on 91 octane fuel and I'm in the 100/100 club. Power starts at 2K and keeps going all the way to 6K. Mucho Funno! I found "big torque down low" to be not as much fun as power all the way to 6 grand. Almost forgot: 40-45 mpg avg. (less if I'm twistin' it all of the time) on the crappy 10% ethanol gas we have to live with now.

 

I am running a 10.6:1 103 build, Wiesco forged pistons +5.5 cc domes, Tman Performance heads 88cc 1.940 intakes, Tman TR625 cams, .030 head gasket, roller rockers, SE 50mm TB. Have not done dyno tune yet, still dong breakin, this was after I had the same build except originally it was with Flat Tops. same build with Flat tops made 100hp 113 tq but I wanted to get all I could out of the cam and heads so went to the domed pistons. No detonation issues at this point. so by changing the pistons and using a .030 hg instead of .040 I went from 9.7;1 to 10.6:1. Before the piston swap the tourge would hit 100 at around 2700rpm and pull to about 5500rpm. . I suspect by increasing the comp it should drop that a little closer to the bottom and by going to a bigger tb should pull up to rev limiter. We will see next week.