10:1 or 11:1?????

[Buffalo400]

If I put a 11:1 piston in my engine, the consuption of oil will be considerably higher than a 10:1??? What is the better set up for a good fiability engine and a little bit of more power???

407cc 10:1
407cc 11:1
I dont want grind it to 416 because if I have a motor problem, I will can grind it to 416.... And I heard someone say that the 426cc have problem of overheating with a stock oil cooler....
Thanks
Buffalo400

[RiPPiNiTuP7]

I'd go with the 11:1.

Originally posted by RiPPiNiTuP7
I'd go with the 11:1.

[Texan32]

from the factory, i believe the comp. is 9.5:1 ish... you are not going to see any gains unless ou go with at least 10.8:1 or 11:1 compression ratio. Since getting an actual 11:1 is so hard (decking cylinder, head/base gasket thickness....) you might as well go with 11:1. You will need to run 93 oct. gas at a minimum though.

stock bore is 397 cc
.040 overbore = 406
.080 overbore = 416
.120 overbore = 426

mose times .080 is as far as you want to bore a cylinder. But the 400ex sleeve has shown that is can handle a .120 bore. Yes, the 426 has a slight heat issue, but that is nothing that a set of air scoops, synthetic oil or secondary oil cooler couldn't easly handle.

Also, since you are thinking of pulling the motor apart for a rebuild, you might also want to think about putting a more agressive cam. There are MANY differnt companies that make cams. An inexpensive yet good cam is the Hot Cam.

[Buffalo400]

Yes, I Know for the gas... it's not a problem for me... I just want a good fiability bike because I dont want problems.... If a 11:1 is well, I'm gonna buy a 11:1....:)

[Texan32]

the only reliability problem i have heard of is really with gaskets. Its seems that some here have problems with Cosmetic head gaskets. Other than that....