Topic: question on vavle lash adjustment

[eldar]

Ok 78 750K

Trying to adjust valves and I have one hell of a tick now. It increases  with rpm.

My questions is this. The cam moves the arms up and down. Is up closed or down?

I can adjust fine with the adjustment part of the arm up but this caused ticking. Are they supposed to be down??

The bike runs and does not seem to be bending vlaves and I will not ride it till they are right.

I hope there is no damage.

Is UP closed or DOWN???

[DammitDan]

When the lobe hits the rocker arm, it pushes the valve open.  If an arm is on the top part of a lobe, then the valve is full open.  If it's on the flat of the cam, then it's full closed. 

A cylinder at TDC will have a very little bit of free play in the rocker arms.  Cylinder 1 and 4 move in sync, but only one is at TDC at a time (that's what I screwed up on).  On the 650, if cylinder 1 is at TDC, then #2 exhaust and #3 intake will be closed and servicable (e.g. on the flat of the cam) while #2 intake and #3 exhaust will be open (on the lobes).  The same vice-versa.

In other words, play with rotating the crankshaft until you get free play in the rocker arms on either 1 or 4.  Then you'll know which is at 1.4 TDC

[eldar]

Well if I have it done wrong now that method might not work. So when lets say #1 is at tdc on the compression stroke, Are the valve adjusters up oi down?? Thats what I need to know.

I need to know the position the screw/nut adjustment should be in.

Should they be higher to adjust or lower?                        Top
                                                                     
                                tappet side                                    N--------------------------  arm         cam side
                     
                                                                                 down

So which way should The nut (N) be?

[Bob Wessner]

When the cylinder you want to adjust is at TDC, both the exhaust and intake rockers should be loose, that is you can wiggle them side to side a bit. In adjusting the the valve, unscrew the lock nut and unscrewing the adjuster (counter-clockwise) widens the gap. Screwing the adjuster screw in (clockwise) narrows the gap. Is this what you are after?

[Dennis]

Eldar,

I think that this is the description you are looking for.
When the valve is closed the rocker arm is "UP"
As the cam turns the rocker arm moves so that the adjuster pushes the valve "DOWN" to open it. The rocker then moves back up to allow the spring to close the valve when the adjuster is in the "UP" position. At the TDC Compression stroke, both valves should be closed. As Bob says above the rockers will be loose. Unless they have been overtightened, then the valve will be hanging open, NOT GOOD!!
I hope that you find this helpful.
Please look at your service manual or the parts list for a picture so that you can see how the parts actually move and it should be a little easier to understand.

[eldar]

The manual did not help. The up/down part was what I was looking for. I cant remember how I did it the first time but the second time I did it that way. I ampretty sure I did it this way the first time too.

Now when doing valves, should the cam chain be done too?

[DammitDan]

I would do the chain before the valves.  If adjust the valves and then adjust the chain, the extra bit of tension that wasn't there before might slightly throw off the valve adjustments as well as affect your timing (depending on how loose your chain was). 

It only takes a minute or 2 to adjust it.  Go for it (with the engine shut off and hand-cranking the shaft...)

[eldar]

That sounds like it might be a plan...... Me? use a plan???

[Kelvin8]

I used to adjust the valve lash on my 350 by ear with the engine running. Faster and more accurate. Loosen the lock nut adjust the screw until the valve becomes quiet and lock it down. I was young and foolish then ... but it worked.

[eldar]

I dont know if I could move fast enough to keep a screwdriver and wrench on the nut while the engine is running!

[DammitDan]

Jesus... I didn't even think you could do it with the engine running... Unless you stop it to adjust the valves, then restart it and listen.