Hi there, I'm after an exploded diagram of the engine on a Yamaha YFM400FA (5GHOO Y-2) Kodiac ultramatic quad bike. Can you please direct me. Thanks Mike Clark

https://www.manualslib.com/manual/1161671/Yamaha-Kodiak-Ultramatic-Yfm400fa.html

possible skipped tooth --installed wrong

IS THE CARBURETOR AIR FILTER CLEAN?

loose or pinched a wire under plastic

You will need to replace the head gasket. Tightening the head will not work once the oil has found a path to leak out.

rev high in first, shift to 3rd. repairing 2nd is a total pita

Hey Jason,

What?? .. slow down and give me more specific detail.. this is not a complicated problem .. just need more info.. could be a simple clutch adjustment... or you need new clutch fiber plates??

Forget the engine number it means nothing. The 17 digit serail number is what you need. It is on the black main frame L.H. side in front of footpegs. That will tell you what model year & size the bike is.
Next, No Spark (a very common problem) is never the ignition coil bad. First, ck that the plug is not black fouled (replace--don't clean). Second, make sure the kill switch is on run. Third, It is probably(95%) a bad Stator/Pulser coil in the L.H. side of the motor that can be checked with a ohm meter at a Yamaha dealership easily.

Go on ebay and buy a new CDI computer those bikes are notorious for computer failure.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/brandon_79b580f5a99c4386