450F Yz450F rebuild

Whats up everyone.

Im getting ready to do a top+bottom end rebuild on my bike.
Just wanted to know are there any tips you guys can give me that may be helpful?
I've been watching many YT videos on the topic, gaining as much information as possible, trying to retain all thats necessary so I dnt make any small mistakes like not lubing parts, anything.
This my first time and I dnt want to F any new parts I install in bike right away, lol, so please any advice/tips that you guys my feel I need, or wish you knew during your first process.
 

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SRAD97750

Moderator
Staff member
Clean everything. Extra time at the parts wash, or a wire brush are well worth it.
Label hardware in ziplock baggies. You don't know how long this project may be apart. Ask me how I know.
Pay attention to how each component comes apart, what orientation.
Take pictures of everything/anything you don't want to try and figure out later, such as all hose, wiring, and cable routing. "Did this cable go over this hose and through the frame?"
Dry assembly is a good idea before trying to finalize any step.
Rags or paper towels over/in openings keep hardware from falling deep into the engine.

Know that something else will pop up during the inspection (or reassembly) requiring replacement or delays you didn't expect. Just know it usually doesn't all happen in one 'shopping trip.'

Enjoy. If it's not enjoyable, take a break and come back to it.
-BIG DAN:thumb:
 
Thanks for the reply. I was doing just about all this BUT the zip lock baggies(being lazy thinking I can remember‍♂️). I brought some to the garage, just havent starting using any yet but will for sure later today when I take motor off bike and start taking off all the bolts on left and right side.
I think Im ready. Rest of my tools I ordered will arrive tomorrow, like my crank case splitter, Flywheel puller, ect. So hopefully tomorrow I will have case open.
 
Not sure what year you have, but I have a brand new hot rods YZ crank in the box unused for a 2007YZ 450. I would make you a hell of a DBA deal on it
I got 2008. I tore engine down and split it. Crank is still good. Just blew the piston, bunch of shavings inside bottom tho so gotta clean it.
Where I circled, chipped a lil of the inside of case, so gotta find someone to weld it, if possible, otherwise would be forced to get another case.
Thats the part where oil goes Im pretty sure, crank had to be knocking against it, chipped one side a lil, and put small crack on other.
Anyone think its possible to weld and be good to go? If so, what might be the ball park number ti weld it
 

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Looks like it's still possible to save it with JB weld!
-BIG DAN:thumb:
Im waiting on 2 people to get back to me about possible weld, but in mean time, can you explain what process is possible with JB weld? Like just use the weld and my fingers to like form the peice of metal that belongs there? Lol, sorry if my question sound stupid but just trying to get an idea of what you are suggestion. Or were you talkin aout jb weld being able to save the side thats just a lil crack?
 

SRAD97750

Moderator
Staff member
I must have misinterpreted the first picture. I was referring to the cracked bit, where all the material still exists.
Did you try to pry the cases apart with a tool, by chance?
-BIG DAN:thumb:
 
I must have misinterpreted the first picture. I was referring to the cracked bit, where all the material still exists.
Did you try to pry the cases apart with a tool, by chance?
-BIG DAN:thumb:
Crank case splitter is how I split it. Possible I did that when splitter case? Man I always have "great" luck
 
I’ve used JB weld on several different cases with damage much worse than that, all are still holding up after 10 years or more. Just make sure that when you’re done and ready to reassemble that the mating surface is true, with no high spots.
 
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