Just some hints I collected over the past 3 hours installing an '06 YZ cam into my 2012 WRF:
- you have to get the park plug out, make sure you have a socket for it
- after removing the whole tank loosen the two screws that hold the electricity panel in place.
these screws are on the underside of the left and right side studs of the frame.
You then have a chance of relocating that dreaded electricity rack a little bit fore, aft and up(!)
- while you are at it do make sure the cables above the cylinder head cover are CLEAN, or you will drop debris into your engine
- you need a lot of light from the left side, just saying, for those guys with dark garages
- tuck the spark plug connector and the engine ventilation tube (1/2" tube coming out of the cylinder head cover) out of the way
- make sure the rubber gasket stays with the cylinder head cover. it's easier to reinstall that way.
tilt the cover to the left to loosen the right side. when trying to lift up the cover "help" the big rubber sections on the left side by pushing them upward, too
- you only have to reomve the exhaust cam cover, intake can stay installed
do NOT try to grab these four bolts singlehandedly, they are oily and might vanish into the engine
- be very careful when removing the cam cover the first time.
it might be very well seated, but it contains three items that very easily might fall into the engine:
two hollow dowel pins and the 180° circlip positioning the cam bearing.
DO NOT remove the cover by passing it over the cam chain cavity
- don't forget to remove the cam chain tensioner, we need all chain slack we can get
- grab some wire and fix the cam chain to the intake cam sprocket tightly. it is possible to remove the exhaust cam with the intake cam seated and still wearing the chain
- the 3 'o clock and 9 'o clock punches WILL align perfectly with the cylinder head top IF you tension the chain by pressing your finger into the chain tensioner openeing while checking their positions.
Did I mention you do need lots of illumination from the left side?
- do not rely on the number of pins between the 12 'o clock punches on the sprocket:
my WR'12 had 14 pins stock, with the '06 YZ exhaust cam there were only 13 pins between the 12 'o clock pins with the cams perfectly aligned to the cylinder head
- never turn the crank 360° w/o the chain tensioner in place and active. the cam chain WILL skip one tooth per revolution on each cam, even with the cam cover tightened, BTDT.
If that happens you have to realign both cams!
- should you have to realign the intake cam be very careful not the drop the chain into the engine
route a thicker isolated wire across the cylinder head through the chain.
It IS possible to get the chain back over the intake cams sprocket w/o removing the cam or even its cover.
You might not believe it but the is enough clearance between sprocket and cylinder for the chain so it can be moved "in front" of the sprocket.
But you won't need to do that beacuse you payed attention and 1) fixed the chain to the intake cam sprocket and 2) did not turn the crank w/o chain tensioner installed, right?
- don't try to reinstall the cam cover with the 180° circlip installed.
Put the circlip onto the bearing (make sure the bearing sits snug in its boss) and hover the cover over it. it's hard enough to prevent them dovel pins from falling out
Edited by WRF-Rowdy, June 02, 2015 - 06:15 PM.