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yfz450 case


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it would be a pretty major job... if you havnt done any engine work before i would have someone with experience do it... probably the best way to do it would be to remove the head and jug and turn the motor on its right side keeping the crank and transmission shafts vertical... you should be able to remove the case half and replace it without anthing falling out... I have done this with splitting banshee cases and it works pretty well... if you do it i would get a service manual...

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If i do what you say and remove the head and jug keeping everything vert. do i have to worry about keeping from moving on the inside, or will everthing stay in place while removing the LH side of the case the only thing is on the yfz450 the swing arm is conected to the rear of the motor i cant remember or not if the part where the swing arm is conected to the motor splits or not

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I just got thru going thru the headache of the left case my self:aargh: i did all the work in a friends basement(minus machine shop work) it is a pain, but it's not that bad with a repair manual. after all the research i've done, from 04 to 08 all parts are interchangeble, some parts have improved since 06:yes: some have degressed since then(i cant verify it, but i beleive they changed the piston for better reliablity, and i beleive a loss of power) but thats just my :twocents:. the change in the cases is a plus. the 06 up has an added oil jet that lubes the bottom of the piston:yes: but you can get a kit to upgrade the 04/05 cases too. i'm not sure exactly about dirtbike to quad conversions, but I dont believe so.. the YZ has a smaller flywheel and stator, the YFZmotor is based on the WR version, but i dont know how close, i think the cases are different due to lack of oil res on the dirtbike.. DK for sure...:no:

alright for the task at hand..... the cases are matched from the factory:aargh: so you have to have a matching set to ensure proper alignment of everything (bearings and coolant chambers).. after the head and jug are off, if you dont have access to any special tools, leave the fly wheel ON the crank if it doesnt come off easily your supposed to have a puller to do it properly..(left side) the engine disassembles from the right side Up:bangheadc: the left case is the "base" so after you remove the right cases,(inner and outer) and the tranny,,,,, whether you got the fly wheel off or not you then take your old left case to somebody that has the tools and the stuff to Press the old crank off of the old left case and press it into the new case:rantc: be sure to have the head and valves checked and adjusted while its off and easy:wink: be sure to lube, loctite and torque every thing to spec, and stay calm while reasembling the tranny shift forks and shifting drum:err:..

Good luck with it! Keep me up to date on your project! Holla if you got any questions, I do the best i can to help out!! I'm out of breath right now..lol

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the only part of my quad that i haven't had apart is the carb.. that will be very soon tho:no: my airfilter took a dump :fart:in the last race and now i've lost some compression, not sure how much, but i can tell a diff in the way it sounds and feels. it's not smoking, but i'm not going to give it the chance!! I think its time for a GYTR high comp piston, GYTR full stainless exhaust, and GYTR air filter and jet kit:cheer2: that should bump it over the 65+ HP mark:wink: gonna be some dough tho!!!!!!!!!!!!!!!!!!!!:skeptic: atleast i'll have an excuse to tweak the carb!

So While your in there YFZ450.................. check on some of the GYTR stuff, its high, but its the best!

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