Ok, i heard that on the yamaha website it says that this bike(atv) has like an 11:1 compression, and somebodytold me that the mx bike has 12:1.....hmmm would yamaha really do a thing like thi sto us? i guess the carbs are the same, but as for the cam/ exhuast pipe, who knows......the end hole on the pipe stock is really small, like a z400, i know that the mx bikes come with a nice free exhaust, and loud...whell, thats and easy fix anyhow!!

 

The specs on the yamaha site say 11:9:1 compression. Thats 12:1 if you ask me.

 

Yamaha lists the compression at 11.9:1 which is slightly lower than the 12.5:1 of the bikes. I would presume this is due to the added weight of the quad for keeping detonation in check.

I think it was ATVNews that said the quad has the YZ intake cam and the WR exhaust cam, which means that very little detuning has occured.

The exhaust (muffler) looks like the same one on the Raptor which means that it can be uncorked some by removing the spark arrestor.

It is my guess that very little detuning of the motor has been done. I don't expect it to have the HP of the YZ bike, but it should be very close to that of the WR, which is the motor used as the platform for the quad.

I would really like to have one myself.

Buttermilk385