416 compression

[FullBloodFreak]

With a 416 kit,XR400 cam,filter,pipe. Will higher comp. make a big diff in power? 10.8 vs. 12.5? How high can you go? Pro's/Con's.

[400exBro]

I would look at the 11.1 comp. you can run 94 pump gas but any higher you need a mixture of race fuel and pump. 10.8 is okay but the 11.1 gives out more torque.
Look in the ex tech or home page under mickey dunlop's answer that were sent in, there is some great stuff on what comprasion and set up to run ect..
lata
400exBro

[kabd69667]

with 12.5 to 1 you'll have to run 110 octane. You will get a lot more torque with the 12.5 than the 10.8. If gas isn't a prob. then go with the 12.5 to 1

[FullBloodFreak]

Gas not a prob. Other than more $ any con's?

[wyndzer]

Go with the 12.5:1, make sure it is a flat top not a dome. Also use an XR400 head gasket to keep compression ration 12.5:1. The TRX gasket will actually make it less than 12:1.

[Dave400ex]

If you get a 12.5:1 Piston, XR400 Cam, Air Filter, and Pipe you will have a Torque Monster. What kind of Pipe are you going to get?

[FullBloodFreak]

Probably Pro Circuit. I need the SA. Should be pretty quiet,too. I ride a lot in the Nat. Forest. Ride MX 2-3 days per week but don't want to change cans to woods ride 1 time per week.

[kabd69667]

I think the p.c's are kind of loud. If your worried about noise, try modifing your stock pipe

[Dave400ex]

Pro Circuit is very loud. The guy I ride with has one on his 400EX and it`s loud. It`s not as loud as mine, but if he gets on it hard, you know it. I would get a FMF Powercore Q and PowerBomb Header.