09 Yamaha yz 450 engine rebuild

Hello it's my first time rebuilding a 4 stroke yz 450 engine. Not only that it's my first dirt bike engine rebuild ever. I'm looking at rebuilding the entire engine I salvaged what I could off my old crankcase as the old crankcase is garbage. I'm buying a new crankcase and other parts needed to do this build. I was just wondering if anybody could give me tips on how it's done and If anybody knows what kind of tusk tools are needed to do this build if you could let me know that would be awesome thanks.

Are you just getting a whole new bottom end or just new cases. If you are splitting the cases and swapping the good parts into the new cases I would recommend getting a manual. The $10 eBay ones are just fine but it will save you a lot of time and frustration. Also im guessing you threw a rod if you need new cases? So you will need a flywheel puller to get the old flywheel off so you can put in on the new crank. Case splitters are not needed, there are tabs on the cases where you can pry them apart with a screwdriver. You'll need feeler gauges for setting ring gap. If you plan of lapping the valves and replacing valve seals you will need a c clamp style valve spring compressor because the other style will not work on a dirtbike. Torque wrenches are a must for things like cam caps, head studs, magneto/flywheel bolt ect.
As for how it's done, just follow the manual. It will give you step by step instructions on how to do everything, disassembly and reassembly. Also Test the trans as soon as it's back together, before you but the clutch and stuff on because if something isn't right it'll save you a lot of time not having to take the clutch, oil pump, ect off to fix the issue. Other then that, keep bolts with their covers or what I've found is take a pick of cardboard and cut slots that max up to the cover bolt holes then stick the bolts into the cardboard so you know exactly which bolt goes where. Just keep things organized and follow the manual and it will go more smoothly, if you really want to be organized get a sharpie and a box of gallon freezer bags and label things and put them in the bags, bolts don't get lost as easy and parts stay cleaner.

I'll definitely follow your instructions on what you've given me I am doing a complete rebuild I just salvaged what I possible could so far I'm looking at replacing the crankshaft, rod, piston, cylinder crankcase along with all the crankcase bearings and such everything else looks good to reuse i plan to get wiesco parts im somewhat thinking of a big bore kit just can't really decide so far I have emptied the old crankcase just have to buy all the new parts and do my best to put it all together

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