Topic: Valve adjustment

[Z-MO]

So I am putting my motor back together for the first time and trying to do my valve adjustment.  According to the manual, with the timing index lined up with the 1-4 cylinder T mark, #1 piston at TDC, I should be able to adjust #1 IN & EX, #2 EX and #3 IN.  Both tappets on #1 cylinder are no problem but #2 EX and #3 IN tappets are touching the valve with the screw all the way out.  Any ideas what my issue may be?

[MCRider]

So I am putting my motor back together for the first time and trying to do my valve adjustment.  According to the manual, with the timing index lined up with the 1-4 cylinder T mark, #1 piston at TDC, I should be able to adjust #1 IN & EX, #2 EX and #3 IN.  Both tappets on #1 cylinder are no problem but #2 EX and #3 IN tappets are touching the valve with the screw all the way out.  Any ideas what my issue may be?

I think you have piston one at TDC but not on the compression stroke, but on the exhaust stroke. To be sure you have it on compression, do this. Turn the crank thru while watching #1 intake go down. Then it comes back up. NOW watch for the 1-4 T mark. This will be #1 CTDC (compression TDC).

I don't know if the manuals fail to specify this or what, but that's the deal.

[Z-MO]

Thanks MCRider, I will try that.  Manual definitely did not specify that...I read that section over about 15 times looking for something I may have missed.     

[MCRider]

Thanks MCRider, I will try that.  Manual definitely did not specify that...I read that section over about 15 times looking for something I may have missed.     

I haven't read my manual on the issue in quite some time. That's just how i always do it. Never a problem.

As much as we would like to impart special authority to our manuals, we all have examples of inadequacies. We just learn them and work around them.

I was taught this method first hand, hands on, and may never have read a manual on the subject.

[bollingball]

Nothing wrong with MC way but as in a lot of things there are different ways to get the same results.
 First I take out the plugs to make it easy to turn the crank. then I put my compression gauge in #1. Then start turning the crank with the kicker slowly while watching the gauge. When it first starts to move I take out the slop in the kicker and bump it with my fist while looking at the index mark and stop when it lines up. different strokes for different folks.

Ken

[MCRider]

This got me to thinking... If the bike were running, and you went to do this.

My manual says turn to 1-4T. Then determine which is on compression, either 1 OR 4, by clicking the tappets. Whichever is loose is on compression. So my Clymers does refer to being sure the cylinder you start with is on compression TDC, just in a back handed kind of way. Check your manual. Then its the adjacent EX and the next over IN.

Quote: "At this point (1-4T) either No1 or No 4 cylinder will be at the top dead center (TDC) point of its compression (italics mine) stroke. Find out which one it is by feeling the rocker arms of both cylinders through the adjustment holes. A cylinder at TDC will have both its rocker arms loose, indicating that both intake and exhaust valves are closed."

Well this started out with promise, in search of the compression stroke. But it dropped the ball at the end by failing to continue to mention that the cylinder we want is at CTDC, not just TDC.

If as you imply you're motor is being reassembled you may not trust this technique as your 1 and 4 were never set to begin with. So you'd need to use a positive method to determine that #1 is on compression and not exhaust stroke. If it were on exhaust stroke you could still get the valves adjusted I think as they would be on the "overlap" area of the cam and it would fool you into thinking it was OK. The tip off would be that you can't get the adjacent EX and next over IN to adjust.

[killersoundz]

When I had my engine apart I just adjusted the valves when the cam lobes were on the "closed" positions. If that makes any sense. Seems to have worked fine

[lucky]

So I am putting my motor back together for the first time and trying to do my valve adjustment.  According to the manual, with the timing index lined up with the 1-4 cylinder T mark, #1 piston at TDC, I should be able to adjust #1 IN & EX, #2 EX and #3 IN.  Both tappets on #1 cylinder are no problem but #2 EX and #3 IN tappets are touching the valve with the screw all the way out.  Any ideas what my issue may be?

It can get confusing but let me make it simple.
When you are adjusting the valves for each cylinder. BOTH cam lobes for that cylinder, should be pointing DOWN at a 45º angle and the piston is at TDC.

THATS IT. That is all you have to know!  Forget all that other stuff.

[MCRider]

So I am putting my motor back together for the first time and trying to do my valve adjustment.  According to the manual, with the timing index lined up with the 1-4 cylinder T mark, #1 piston at TDC, I should be able to adjust #1 IN & EX, #2 EX and #3 IN.  Both tappets on #1 cylinder are no problem but #2 EX and #3 IN tappets are touching the valve with the screw all the way out.  Any ideas what my issue may be?

It can get confusing but let me make it simple.
When you are adjusting the valves for each cylinder. BOTH cam lobes for that cylinder, should be pointing DOWN at a 45º angle and the piston is at TDC.

THATS IT. That is all you have to know!  Forget all that other stuff.

Assuming no rocker box of course.

[Z-MO]

Thanks for all the input guys.  I feel like I am starting to understand all of this better.  Off work early today so will try your tips when I get home.  Let ya all know how works out afterwards.

[lucky]

So I am putting my motor back together for the first time and trying to do my valve adjustment.  According to the manual, with the timing index lined up with the 1-4 cylinder T mark, #1 piston at TDC, I should be able to adjust #1 IN & EX, #2 EX and #3 IN.  Both tappets on #1 cylinder are no problem but #2 EX and #3 IN tappets are touching the valve with the screw all the way out.  Any ideas what my issue may be?

It can get confusing but let me make it simple.
When you are adjusting the valves for each cylinder. BOTH cam lobes for that cylinder, should be pointing DOWN at a 45º angle and the piston is at TDC.

THATS IT. That is all you have to know!  Forget all that other stuff.

Assuming no rocker box of course.

I think you can peek in the tappet cover and see the cam.

[bollingball]

I think you can peek in the tappet cover and see the cam.

You either know or you don't. which is it.

[MCRider]

I think you can peek in the tappet cover and see the cam.

You either know or you don't. which is it.

I went and looked. All i can see is the end of the rocker with the adjuster and the top of the spring (retainer). Off to the side you can see a cyl head nut.  That's all.

So, good advice without a rocker box.

[w1sa]

Another approach to the 'inlet valve' position method (with adjuster screws loose and 'backed-off at re-assembly etc), is to hold upward finger pressure on the #1 inlet valve rocker as you turn the crank....that way,  the rotating cam lobe will still push the rocker down....as the rocker rises again (with continued finger pressure) the crank is now rotating past BDC on #1 (inlet stroke) and headed toward #1 TDC compression (at about  the next 150 degrees +/-say 30deg of crank rotation)...so you should now look for the 1.4 T mark to appear and align in the window.

[trueblue]

An easy way to tell which cylinder is on compression and which is on the exhaust TDC is look at the cam shaft.

[dave500]

i always do them in firing order,i just turn and watch which ever inlet closes,line up that cylinders t mark and go from there,ive never set tappets with the honda book method.

[w1sa]

That's a great method Dave........but, the OP's issue is that he has rockers/valves which aren't set/adjusted to run.......so he needs to identify when a cylinder/set of valves/cam is in a position to set and adjust for correct valve operation

[cgswss]

The way I do it...  I only adjust the valves one cylinder at a time.  I find TDC  for the compression stroke and sfjust #1.  Then I turn the crank 180 degrees (1/2 turn) and adjust #3, turn 180 degrees (will also line up with the TDC mark) and adjust #4, another 1/2 turn and adjust #2

Honda clearances are so tight that on the intakes you have to push on each end of the rocker arm to see if they have any movement.  Remember, when turning the engine always turn clockwise from the ignition side. I always just use a big socket on the crank to turn the engine.

[That 70s Bike]

Thanks MCRider, I will try that.  Manual definitely did not specify that...I read that section over about 15 times looking for something I may have missed.     

If it's a Clymer, Haynes or the like, they're good for leaving out critical info.
the Honda Factory Manual is a free download at the top of this SOHC/4 bikes page.

[dave500]

That's a great method Dave........but, the OP's issue is that he has rockers/valves which aren't set/adjusted to run.......so he needs to identify when a cylinder/set of valves/cam is in a position to set and adjust for correct valve operation

same way,even if the adjustment is way out too big or tight youll see the rockers open and close the valves.,rotate untill the inlet rocker moves up closing the valve,then line up you t mark.

[w1sa]

What bike???........or did I miss that??

When you install rocker shaft/rocker assemblies, the generally accepted convention (IIRC), is to ensure the rocker/tappet adjuster screws are backed right out....this is to ensure the valve(s) are not pre-loaded as/when you screw the rocker shaft/rocker box down onto the head.

Once you've installed the rocker assembly (for running),  you need to engage the cam lobes and their respective valves, in a correctly phased manner....until you do that, you cannot simply look for the valve to fall and rise..........(unless you install the rocker shafts with the adjuster screws turned in...in which case there is some added danger that they are not as you removed them.......and, even if they are, a rocker box which holds rocker shafts will not be torqued down correctly, if the rockers are pre-loading the valve(s) as you bolt/torque  it (the rocker assembly) down onto the head.

[MCRider]

What bike???........or did I miss that??

When you install rocker shaft/rocker assemblies, the generally accepted convention (IIRC), is to ensure the rocker/tappet adjuster screws are backed right out....this is to ensure the valve(s) are not pre-loaded as/when you screw the rocker shaft/rocker box down onto the head.

Once you've installed the rocker assembly (for running),  you need to engage the cam lobes and their respective valves, in a correctly phased manner....until you do that, you cannot simply look for the valve to fall and rise..........(unless you install the rocker shafts with the adjuster screws turned in...in which case there is some added danger that they are not as you removed them.......and, even if they are, a rocker box which holds rocker shafts will not be torqued down correctly, if the rockers are pre-loading the valve(s) as you bolt/torque  it (the rocker assembly) down onto the head.

Good point, we've been assuming a CB750, or at least i have.

On the CB750 you can back all the adjusters out to a minimum position, as you should as you indicate,  with the contact point just barely below the rocker arm, and all we've discussed as far as the intake valve going down and rising will still happen. It just has a lot of clearance.