I need help with adjusting the valves on the 400 and the 300EX. I have both and they both need to be adjusted. It is like 85 bucks to have the shop do this and I really didn't want to pay it unless I have to. Could anyone detail the adjustmet. Also I assume plastic has to be removed.

 

Do you have the tools needed?

 

not sure what tools do you need?

 

What your going to need to do:

1) Remove front Plastics
2) Remove gas tank
3) You now have access to the top of the engine
4) Remove side bolt on left side of engine. (left if you where sitting on the machine. I think its a hex bolt
5) Before you can adjust the valves you need to be sure the piston at TDC (Top Dead center)
6) If you use a flash light and a socket, in the hole on the side of the engine you need to line up the marks(the lines will form a T). ones on the timing gear the other on the crank. you'll see what i mean when you remove the cover. Turn slowly
7) After you made it TDC you can remove the four caps on top of the head. The two in the rear towards the rear wheels are the intake the other two are the exhaust. This is where you'll need the valve adjustment tool(Can be purchased at your dealer) 20-30 bucks Instructions should be with the tool,
8) Make sure you also have something to measure your valve spacing. The intakes should be 4 thousands spacing and the exhaust valves 5 thousands.There are flat head screws to tighten valves, tighten them down then back off about a 1/8 of a turn. Important note: Before putting caps back on, tighten your valves.
9) Put your tank on and don't forget about the side case bolt ,fire that kid up. Listen for loose valves, adjust as needed.

I know this sound like a lengthly process but really it only took me about 1 hr. Its simple, If you know anybody who knows a thing or two about valves have them help you, I did at first now its a walk in the park. Hope this helps

99' 400ex, +2 Burguards, +4 Axcaliber axle, Works triple rates, Ultra cross rear, DG Alloy nerfs, DG Bumper, WB E-series full system, Race plastic, 18" mx holeshots, trekker fronts, Full skid, Nacs block off plate, motion pro twist, toggle kill switch

 

Spend half of what the dealer wants and buy the services manuals for the 400EX and 300EX (those from Helm are the best).

 

In the recent Issue of Dirt Wheels there is an article on how to adjust EX valves were they used a 400EX

 

December Dirtwheels had the article on 400EX.