It's really 10.75:1!!! So it should run on 91-93 octane pump gas just fine!!!!!!!!!!!![img]i/expressions/face-icon-small-happy.gif[/img]

 

I run a half and half mixture of super unleaded and 108 octane race fuel. 11:1 JE piston and shaved .015 off the head.[img]i/expressions/face-icon-small-happy.gif[/img]

 

now just motor mine is faster on gas than alky but it gets so hot down here and when on nos its just to much heat for the old bike thats the only reasons i run alky

 

11:1 is really pushing it for pump gas. If there is a lean spot at all it will detonate. Remember, detonation always leads to preignition, and thats not good. Can you say melted parts? Thats assuming that the top end withstood the hammer effect of the detonation. With the hemispherical head that the Raptor has, about 10:1 is the max safe limit on pump gas. If you dont want to buy race gas, run 100LL avgas. A 50/50 mixture of 91 octane unleaded and 100LL will give you a actane of about 95 and the bike will love you for it. To exceed about 10.5:1 even with aluminum heads, you will have to go to a combustion chamber design with a better squish band and one with preferably a bathtub design. If you choose not to spend the money on having your head redone, then you will need to consider alcohol as it is somewhat more forgiving. (all alky engines need to run somewhat richer anyway, and present their own set of problems) But thats another story alltogether.

Note:
detonation = uncontrolled burn(explosion) after timed igniition
preignition = uncontrolled burn before timed ignition(from the heat caused by either glowing parts or carbon, which is due to the heat from the rapidly expanding gasses from the detonation)

 

The hammerring effect could easily apply enough stress too overload the stock rod.

 

I know for a FACT detonation had nothing to do with it!!!!!!!!!!! That's not to say it couldn't happen!! It just didn't happen in this instance!! Just take into account that this happened about 4 weeks after installing the cam and piston. If it was detonation wouldn't it have happened from the moment it was fired up after assembly?[img]i/expressions/face-icon-small-confused.gif[/img]

 

Extreme, wht type surface were you riding on when she let go? The reason I ask is because I had a theory that you were on hardpack which provides maximum hookup which in turn is harder on the engine. Not like sand where you are spinning a lot more or gravel. What do you think?[img]i/expressions/face-icon-small-smile.gif[/img]

 

Delta- I was riding on a caliche road (which is a mixture of white colored clay and gravel) when she let go. Your theory sounds pretty good, but it still shouldn't have let go like it did! Just look at some of the set-ups being run on stock rods!!!!!!!! My set-up is very MILD compared to some of the other bikes on this forum!! XR