Want to rebuild 400ex

[alex10]

I have a 2000 400ex that smokes when cold and burns oil. The previous owner told me that it had a 406 piston kit. I'm going to install a 11:1 Wiseco 416 piston kit and new valve seals. Also what is involved with a valve job on these engines? I have taken my RM-250 apart and split the cases and put in a new connecting rod and piston so I know how to work on engines, how much harder are these 4 strokes to work on? I plan on taking off the cylinder and head and letting the machine shop bore and hone the cylinder and then have them do a valve job on the head. What jetting should I run for this at 1371ft of elevation summer temps around 80? How much is a good service manual and where can I get one. Is there anything else I should know about taking these engines apart? thanks

[alex10]

I found some parts.
Piston http://cgi.ebay.com/ebaymotors/HONDA-TRX400EX-TRX-400EX-JE-PISTON-2MM-OVER-10-8-1_W0QQcmdZViewItemQQ_trksidZp1742Q2em153Q2el1262QQ categoryZ43977QQihZ019QQitemZ290231099632
Cam
http://cgi.ebay.com/ebaymotors/HONDA-XR400R-STAGE-2-CAM-CAMS-XR400-XR-400-400R-96-04_W0QQcmdZViewItemQQcategoryZ35595QQihZ020QQitemZ 300232615088QQrdZ1QQsspagenameZWDVW
Service Manual
http://cgi.ebay.com/ebaymotors/Honda-400EX-OEM-Service-Manual-2005-2007-NEW_W0QQcmdZViewItemQQcategoryZ34237QQihZ008QQitem Z180252689719QQrdZ1QQsspagenameZWDVW

Do all these parts look good?

[drew416ex]

4 strokes arnt really too much harder. Its just those few minor things like valves and timing but its nothing to worry about. Go ahead and get some new valve seals while you have it apart and they are doing the valve job. I would say try a 42 pilot and around a 160-165 main jet on 93 octane. Thats what I ran in my 416. A clymer manual shouldnt cost more than $15-$20. I can see what cam that is, but that is a good piston. If you want to spend a little less you can get a wiseco for $110-120. They are good pistons, but I prefer JE or CP pistons. Also if you dont have on get a good torque wrench that does inch pounds and foot pounds.

[alex10]

How much is a valve job and do I need new valves?

[drew416ex]

They will tell you if you need new valves. They should lap them and see if there are any gaps or if they are warped. If they can they will grind them so they will seat correctly, if they cant you will have to get a new one. I think it is around $10-15 per valve around here and they should replace those seals at no extra cost since they have the springs and stuff off anyways.

[alex10]

Also do I need a different top end gasket set for a 416 piston?

[Honda#4]

Also do I need a different top end gasket set for a 416 piston?

NO, stock size gaskets is all you need, Cosmetic make great gaskets or just go with stock.

[alex10]

How much faster can I expect it to be with the piston and cam? Also my quad has a white brothers slip on.

[Honda#4]

You'll have alot more torque on the bottom end to mid range, i'll let ya know how mine is doing when I get it dialed in and my clutch gasket.