the compression of the cannondale is 12.5:1. will this thing need race gas? that explains why there is so much power! forget efi!

 

if you got a 440 kit on a 400ex and a 12.5:1 piston, wouldnt it make about the same hp? it would save you about $8000!

 

No race gas. Why would it need it? It's less powerful than the 426 YZF...I kow race gas isn't a power matter, but it better run on pump gas!!

 

Horsepower is not the factor for the uses of a high oct fuel.Compression determens the type of fuel used. 8 to 8.5 on comp. can use reg. gas,9 to 9.5 pre. fuel, 10 to 10.5 pre. fuel with additive. 11 on up racing fuel. This saves the motor not nesseecery makes the power.Compression makes power the right fuel makes it work. This is over simplyifing the whole thing.But that how it goes.

RACERJIM

 

no, you need the race gas to prevent detonation. with the high compressions, the gas/air mixture explodes on its own, before the spark plug sparks, and that is not good. think of putting your body into a space that is 1/12 the size of it! you get the picture. i dont get why cannondale would put such high compression on a stocker! people are going to blow them up! hey, i get it, more money for cannondale!

 

I knew it was compression related, although didn't know exactly the ratios.
The Cannondale guys said it would run on pump gas (I read that in a Dirtwheels...don't remember when).
But how do you explain that the 426 YZF (whose compression is 12.5:1) runs on pump gas??

 

i wish i knew! it cant be a pressure relase type thing, because that would defeat the whole thing! have you ridden a yzf? it doesnt say that it requires at least 92 octane gas like the ds650 does? (ds says at least 91) mabey the cooling system is beefed up to demote detonation.

 

the fuel injection is the reason they can the high compresion. The injection controls the timming and the fuel delivery as well as the spark just like on a car, I woud bet it also has a knock sensor.

 

the 300ex is also recommended to have at least 91 ran in it..i use 87 lol

 

well, the 300ex is kinda tuned within an inch of its life! lol. really, are they just trying to keep the engines going longer, or what? high octane isnt good on electric starters, or a kick starters leg!