going to be tearing my motor down all the way for the first time.all tips and tricks welcome

im tearing my 03 yz450 down to do the 5 speed wr swap here soon.ive done big bore kits and cams and what not,but have never been any farther down into the motor than that. i feel confident in doing this but would like to get all the info i can from you guys on this.thanks a lot!!


ha, man it just must be that easy then huh?

Just take your time and pay attention to how thing are when you remove them. Be sure to lay everything out nicely to make it easier when reassembling it. For some tips, go to youtube and search johnnyshop. He has an example of a yz250f rebuild. It's the same as the 450, just smaller internals.

Having a big work area helps alot.

Keep track of all the different sized orings!

Why yamaha used that many on 400,426 and early 450 is beyond me?

I take a lot of digital pictures for later reference if needed and put all related components into ziplock bags as I take them off the bike. I write what the component is on the bag with a sharpie to speed things up later. Hope this helps!

heres what i would say

first and formost get a manual and read it.

torque everything properly don't just assume you know how tight it should be.

tape, baggies and sharpies are your friends. bag up everything and write "tranny" or "clutch"

for case bolts, take a piece of cardboard and remove bolts in a clockwise fashion starting at top left, then stick them through the piece of cardboard in order with all wire/hose guides still on the bolts.

go to websites like mrcycles.com or ronayers.com and print out a fiche to help you remember how things go together.

washers are important, sometimes they aren't just washers they are shims or thrust washers and they need to go back exactly where they were and they may or may not be on the fiche, if you cant remember the order they might go in, zip tie them together.

if it had a gasket it needs a gasket. silicone is not a gasket. gaskets take up space and can cause thinks to bind up due to lack of clearance

piston pin clips do go in a certian way, gap goes either straight up or straight down..... seen them come out.

if you have any problems ...post. we will help you

Another important thing to remember is patience. Years ago I was splitting the cases and I got to a point were i was prying them apart, It appeared as they were coming apart, but then I couldn't get them any further. It was about 1/4" separated and i was losing my cool, figuring it was hanging up on something. well it was, i missed 1 bolt the was either behind the stator area, or in the transmission area, i can't remember exactly. But before I knew it, I heard it crack, and I had broken my case. It was very unfortunate, after I broke the case, I paid little attention to the order of disassembly of the tranny, and bottom line was, I never got it reassembled. I wound up selling off parts from the bike.

these days, with youtube, and all the other information available, I feel there is a much better chance for success, just take your time.

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