400ex to a 406ex

[bodfper]

I am rebuilding my 400ex to get reliability and performance. Here are my plans.
- wiseco 86mm 11:1
- crf450 cam chain
- stg 2 hotcam
- kibblewhite valve springs

Do you guys think that GTT studs are necessary? What would a perma-cool secondary cooler do for me? Is there any Head porting I can do alone? What do I have to do to the decompressor on the cam, anything? Thanks for any input.

[-TheDude-]

why not go to a 416???? it wont cost much more for the piston maybe 10 bucks

[mineralgrey01gt]

the only thing you take off the cam is the cam gear thats all. Id buy new bearings also for the cam and such. I agree with the 416. I did it and glad I did.

[Pipeless416]

10 extra CC's will give you a very insignificant bump in power. the power increase you'll feel is from the bump in compression. all you'll gain by going to a 416 is one less overbore that can be done before resleeving. not worth it IMO. as for the cam, take out the plunger and spring. the GTT head studs would add extra insurance, but before dishing out the money, i would try it. if it blows the head gasket, do the studs. again, thats more of a compression thing than a bore size thing.

[bodfper]

Do I need to worry about the plunger and spring when I put a hotcam in or can I just put the sprocket on the hotcam and be good to go.
Where is the plunger and spring, on the cam or in the head?
Also would the secondary oil cooler be worth it or am i wasting my time/money doing it?
THANKS

[VTredneckgames]

plunger and spring are in the head under the cam.

Im running a 11:1 406 with the factory studs. No problems so far. Im also running factory cam.

I would run a spal fan before adding a cooler. That and maybe some air scoops should be enough to cool the motor.

[jelrod05]

plunger and spring is in the head take it out and put the cam in and put sprocket on it.

[bodfper]

What is the best method for doing the SPAL fan? Is it possible to have kick on by a temperature? Any input would be helpful, THANKS

[jelrod05]

i bought the spal fan kit on ebay and it runs with a toggle switch very easy to install

[VTredneckgames]

there is a very good and lengthy instal thread that mentions how several members done the SPAL fan.

http://www.exriders.com/vbb/showthread.php?s=&threadid=391138

[bodfper]

Another Question I have is should I put a crf450 cam chain on? It looks a bit complicated and if it isnt necessary i wont do it.
Also I have kibble white valve springs, are these going to help me over stock springs? When I replace valve seals is there anything else I need to replace? Thanks

[VTredneckgames]

I would replace the chain. I did. It took only an extra 20 minutes to install it. Cheap insurance. They will need to be replaced at some point. Why not now when its apart?

Dont worry about the valves unless they are bent.