yfz rebuild

[hammertime55]

this will be my first rebuild on a 450 and i had a few questions. My case got busted so i figured while it was completely apart it was time to freshen it up. Its an 04 and i was thinking about going with the 449 crank (1.4mm bigger? i think?) if i go with this do i have to have any kind of machine work to the head or anything? i plan on running my stock head for a while until i can afford all new valves and cams. Also i was gonna go with the stock bore wiseco. Im assuming its the same compression but if the crank is 1.4mm wouldnt the compression go up as well? Any better ideas for piston im always open for. Ive heard good and bad with wiseco. Again this is the first time ive had a 450 apart and i have an experienced buddy thats going to do the work with me so it doesnt grenade as soon as it fires up lol Any input is much appreciated, thanks in advance.

[hammertime55]

according to motosports website if you buy the 1.4mm kit you have to machine the head 2mm for clearance?

[Ride1Rob]

You don't have to do any machining. The heads are all the same. I've rebuilt 3 yfz's with the older motors and dropped the longer cranks in them. It will raise your compression from 11.5:1 to 12.5:1. Have the valves and springs been replaced?

[hammertime55]

No. Its still got the stock valves and springs. That's next on my list

[2muchquad]

i just dropped the 06 to 09 crank in my 05 yfz.It will drop right in,nothing xtra is needed.:)