I have 01 yz 426 and I cant figure out the timing. If the marks are lined up then the lobes on the intake cam are facing a different then ill the ones I see on youtube videos someone please help

the cam shaft may be identifiable but I doubt it as the lobes will be all the same .It may take a trial fitting of the cam shaft to determine which is which. Place the no 1 piston on TDC and install the cam in the exhaust side of the head. position a the no 1 piston cam lobe in the just closing position. Check where the timing mark will be in this position ( the engine make and sized would have been an enormous help here as the key position or timing mark on the gear would have revealed what cam it was). Place the other cam in the position where the no1 cam lobe is just opening.. This is called valve overlap and from the positioning of the timing marks will show if the cams should be interchanged . The marks will either both face down, face each other or face upwards. If they face out wards away from each other then interchange the the cams and if that makes the marks face each other then it may be right. Another way ( probably simpler will be to put a cam in place and the cam lobes will be directly in line with the rockers over the valves or directly over the valves. Workshop manuals are a big help when doing this work.

Hi mate didn't get any info on what bike you are timing but this procedure is simular for most and is specific for WR YZ 250 426 and 450

set piston to TDC (top dead centre) this can be done by spinning the fly around until you can see the (i) mark stamped on the flywheel line up with the marks on the inspection plug hole (engine case) good idea to probe the cylinder through the spark plug hole to confirm the flywheel mark is correct (I have seen several 426) where the TDC mark does not give accurate TDC on piston so worth second guessing this process.

once TDC is set do not allow piston to move from this point on - starting with the exhaust cam with no slack on the cam chain the dot stamped on the cam sprocket should align with the face of head with the cam lobes pointing outward roughly 45 degrees towards the front wheel when this in place

you do the same with intake cam except the cam lobe will face opposite direction outward and the should be a dot aligning to the head

double check before you go further that when you put your finger in the chain tension hole and you tension the cam chain that when all slack is taken from the cam chain that your dots on both cams align with head face and that you still have piston at TDC if all checks out then this is timed set correct so torque all the cam caps back up install chain tensioner and the recheck all fly wheel marks are in correct position and piston is at TDC and the dot on each cam sprocket aligns to the head if it doesn't then re do the process

don't be surprised if this takes a few attempts as it takes the best of us usually at least two attempts to get all marks to align correctly thats why best to check and double check before you bolt it all down then you can adjust just by lifting one cam out and moving one tooth either direction

You have little room to play with and when you start putting chain on the cam sprockets you will find very little extra chain length to play with you may need to wiggle tug and pull both cams together to get them back in each time but go slow and gentle they do go in they just need to be encouraged

I happy to elaborate on any point if you need - good luck

Regards Jamie

There is no real way to change timing on YZ except change the cam itself to YZ450 cam or simular etc If your wanting to find out how to re install the cams you have already and cam chain then it is simple process but sounds complicated when its written
set piston to TDC (top dead centre) this can be done by spinning the fly around until you can see the (i) mark stamped on the flywheel line up with the marks on the inspection plug hole (engine case) good idea to probe the cylinder through the spark plug hole to confirm the flywheel mark is correct (I have seen several 426) where the TDC mark does not give accurate TDC on piston so worth second guessing this process.
once TDC is set do not allow piston to move from this point on - starting with the exhaust cam with no slack on the cam chain the dot stamped on the cam sprocket should align with the face of head with the cam lobes pointing outward roughly 45 degrees towards the front wheel when this in place you do the same with intake cam except the cam lobe will face opposite direction outward and the should be a dot aligning to the head
double check before you go further that when you put your finger in the chain tension hole and you tension the cam chain that when all slack is taken from the cam chain that your dots on both cams align with head face and that you still have piston at TDC if all checks out then this is timed set correct so torque all the cam caps back up install chain tensioner and the recheck all fly wheel marks are in correct position and piston is at TDC and the dot on each cam sprocket aligns to the head if it doesn't then re do the process don't be surprised if this takes a few attempts as it takes the best of us usually at least two attempts to get all marks to align correctly thats why best to check and double check before you bolt it all down then you can adjust just by lifting one cam out and moving one tooth either direction
You have little room to play with and when you start putting chain on the cam sprockets you will find very little extra chain length to play with you may need to wiggle tug and pull both cams together to get them back in each time but go slow and gentle they do go in they just need to be encouraged
I happy to elaborate on any point if you need - good luck

the cams should face 10 and 3 with a 15 pin count on the cam chain pins from top marks on the cams the tdc mark make sure u turn it over by hand to make sure the motor is moving free

Line the (i) mark on the fly wheel to the inspection mark on the inspection plug hole then with both intake and exhaust cam lobes facing outward of the head aline the dots on the cams as best as possible to the top of the head it wont a line perfectly but will be pretty close - the timing on just about all YZ four strokes is exactly the same they all use this set up to install cams

make sure the pison is on top dead centre(look through the small timing plug hole down the bottom) There is a punch mark on each cam sprocket that aligns with the cylnder head surface. the cam lobes facing away from the lifters
Im trying to up load an image of the page in the manual
Comments: May 01, 2010- hope this opens for you

1st set piston at top dead center, which is the top of its travel. after you have verified top dead center, and you are 100% sure its at top dead, install the cams. first the exhaust cam, with you facing the sprockets, with the cam lobes facing up and away, about the 10 o clock position. once set there, you should see a refrence on the sprocket, with lines that will be parallel with the cyl. head surface. then install the intake cam, with lobes facing in the 2 o clock position. once again, you will see refrence marks on the cam sprocket that should be level with the cyl. head surface. after the cam caps are installed, and the cam chain tensioner, turn the engine with the flywheel bolt to verify you have no piston valve contact. after you turn over a few times, recheck timing.

take the sparkplug out and crank it over slowly when air pushes out is usually a compression stroke stop when the piston reach's the top..spin it over 2-3 times make sure you feel air rushing out the sparkplug hole put your finger in the hole it should push your finger out .

Hi there Longhatx....Ok...Turn the crankshaft counterclockwise until the " I " mark on the rotor is aligned with the stationary pointer on the crancase cover.Fit the timing chain onto both camshaft sprockets and install the camshafts on the cylinder head.The camshafts should be installed onto the cylinder head so that the exaust cam sprocket punch mark " E " and the intake cam sprocket punch mark " I " align with the surface of the cylinder head,both marks facing out of course towards their prospective ports.thats about it .Please leave some feedback if this has helped . ride on.

the cams should say ex, int on cam sprockets if not the cam with 3 lobes for intake cam with 2 lobes exhuast, piston at top then set the cams with cam lobes facing outwards almost like a VEE there is i think a dot on each cam gear which must line up with the head. then turn the motor by hand