Valve Adjustment

[cross]

Ok, so i took things apart to inspect the valve clearance and here are the results.
I did it by the book and the directions are easy but kind of different than what i'm used to. I helped my friend while back do his CB900F and i remember that on each cylinder, the cam lobes were pointing away from each other and then you do intake and exhaust valves on the same cylinder. When i put the cams in such way, i get different measurements. Still go by the book?
I will need 7 new shims (if i find the correct size) and can reuse 12 but with doing so, i'll have one exhaust valve at 0.14mm and 3 intake valves at 0.12mm
Is this ok? Otherwise i'll have to buy 4 extra shims.
I posted spread sheet with measurements, shim sizes and the ones needed. I color coded ones that i can reuse.
Any input appreciated
- I also need help with cam chain. Manual states to loosen up lock not and bolt in the back of the engine, those are two separate bolts, right?
And when i loosen it, what do i need to move with my finger so that the spring moves, i cannot put my finger anywhere and same goes for the front.
How do i know if chain is loose? It appears tight but when i rotated the engine forward for valve adjustment i can see that it was getting slack on the top, not sure if that is normal on this engine, on cars there is never any slack while engine is turned.
- Oil is leaking around the front adjuster bolt and rubber plug and oil line on the engine case side, i took it apart and cleaned it, hopefully it will not seep anymore.

[daves79x]

I think you have it about right. Yes, check them by the book, or it'll take forever. You see the zero clearance one is a big problem and why you needed to do this?

Replace O-rings in both places that you have leaks. Get them from Honda, although the one for the oil line is the same as the oil filter bolt o-ring and you might have lots of them laying around.

Camchain adjustment is very simple, but not explained in the manual well at all. It's been chronicled on the forum many times. Hold tension forward on the crank bolt. Loosen the lower rear chrome acorn nut a turn or two. As soon as you get it loose enough, you hear a 'click' and that's the rear tensioner tanking up the slack. Keep holding forward tension on the crank and tighten the nut. You can also watch the rear tensioner move as it clicks, but you have to be looking and hearing for it.

The front tensioner is the same. You can see it operate better than the rear one.

Dave

[EMS]

Ok, so i took things apart to inspect the valve clearance and here are the results.
i remember that on each cylinder, the cam lobes were pointing away from each other and then you do intake and exhaust valves on the same cylinder. When i put the cams in such way, i get different measurements. Still go by the book?
.

I am not sure if I understand this right, but if you measure valve clearance under a lobe that sits at 90 degrees to the valve, you may not get a proper reading. At this point, the cam lobe has started already and the clearance will be less than at the bottom (ground diameter) of the cam. I always measure valve clearance with the lobe pointing away from the valve.

[asacuta]

That no-gap on intake 4 is weird. I wouldn't worry about the exhaust at 0.14; it will become tighter soon enough. I point the lobes 180° from the valve when measuring clearance, but going by the book has to be OK. I also find that the clearance varies a little depending on how you do it.

If the main tensioner doesn't move, you may have to motivate it a little.

[EMS]

The no-gap measurement may be the result of measuring the way he does it.

[cross]

The no gap one, I should of explained that the smallest feeler gauge that I have is .04mm and it does not go in and no matter which way I position the cam I still have no gap.
I still have to check if cam timing is correct too.
Should I recheck torque on the head bolts?
Does anyone have spare cap for side of the valve cover?
One if mine has a crack around the bolt hole and it's where oils was seeping some

Thank you

[daves79x]

First of all, Honda's sequence for checking clearances requires the minimal amount of revolutions/screwing around. And their way has none of the lobes pointing directly away from the bucket. That way has served me well for 35 years and it's easy. Honda's base circle dimensions on the cam lobes is pretty consistent if you took the time to measure them from lift to lift.

Zero clearance on a valve means you can't spin the bucket, but if your smallest gauge won't go in, then for shimming purposes, you can calculate it a zero, as you did.

You can check the head cap nuts if you want, but they never loosen up in my experience.

Your oil leak has nothing to do with the cam end cap - purely decorative. They are still available from Honda - just make sure you order the late model ones - they're different than the early ones.

Reseal the valve cover gasket exactly as Honda describes and you'll have no leaks.

Do I sound like a Honda commercial?

Dave

[cross]

I swapped the shims around and got some gap in no gap valve (i checked valves by following procedure from the manual).
I got the shims ordered, adjusted rear chain adjuster and i did hear it click and move, thanks Dave.
I will do the front one when i get the seal and rubber plug this week.
Now to cleaning up and polishing a cam cover a bit.
Side cam cover, leak must of been from the gasket then, i should still replace it.

Thanks guys

[cross]

First of all, Honda's sequence for checking clearances requires the minimal amount of revolutions/screwing around. And their way has none of the lobes pointing directly away from the bucket. That way has served me well for 35 years and it's easy. Honda's base circle dimensions on the cam lobes is pretty consistent if you took the time to measure them from lift to lift.

Zero clearance on a valve means you can't spin the bucket, but if your smallest gauge won't go in, then for shimming purposes, you can calculate it a zero, as you did.

You can check the head cap nuts if you want, but they never loosen up in my experience.

Your oil leak has nothing to do with the cam end cap - purely decorative. They are still available from Honda - just make sure you order the late model ones - they're different than the early ones.

Reseal the valve cover gasket exactly as Honda describes and you'll have no leaks.

Do I sound like a Honda commercial?



Dave,

To replace "O" ring on the front cam adjuster bolt, the bolt has to come out. Is this easy as it sounds? what is going to happen with chain tension when i remove the bolt?

Thanks

Dave

[EMS]

And their way has none of the lobes pointing directly away from the bucket. That way has served me well for 35 years and it's easy.
Dave

I have no intention to argue with 35 years of experience and our Techincal Director, but when you follow Honda's direction, the lobes on the valves to be checked point pretty close to "away from the bucket". Definitely not "at each other".
Bear in mind, that the valves sit at an angle in the head. A lobe pointing away from the bucket will not point "straight up" or perpendicular to the valve cover mounting surface. I have only adjusted the valves on my own CBXes, so I have much less experience, but I have applied the basic rule that you should check valve clearance at the base diameter of the cam lobe and that has worked fine for me also. I rather take a little longer. I am not under pressure of the service manager to finish that job in a minimum amount of time.

[Rick Pope]

A long time ago, just because I never do what I'm told, or follow directions, I checked a CBX's vales by following the sequence as you would for an inline 6 diesel John Deere.

That being, rotate engine until the #1 cylinder is at tdc. See whether #1 or #6 has slack in the valves, then check both valves on that cylinder, and the adjacent valve(s) on the next cylinder. Continue with every other valve until you get to the last three. Now rotate the engine 360 degrees, and do the same thing, starting from the other end. Quicker than rotating the engine for each cylinder.

Is it correct? Certainly not by the Honda manual. Did it worK? To be honest, it's been so long ago, I forget (early 1990s). But the next time I have a CBX valve cover off, I want to try it again and see if it works. But keep in mind, the JD engine has a top speed of about 2300 rpm, so cam profiles don't need the gentle opening and closing ramps.

[asacuta]

Rotating the engine is the least of your problems when adjusting valves. As long as you're measuring the clearance between the shim and the base circle on the cam, any method you choose should be fine. That said, Honda is unlikely to specify an inefficient method in their service manual.

[EMS]

That said, Honda is unlikely to specify an inefficient method in their service manual.

Inefficient. In this case it has to take the dealer service department into account. This method is designed to make it efficient for a service dealer shop set-up. I am thinking about how many of us follow the exact directions in the service manual to adjust the cam chain tensioners???

[asacuta]

I like measuring with the lobes pointed exactly away from the valve. It may take a little more rotating, but I know everything is in the right position for an accurate measurement. I'm too much of a klutz to use a different method. Same with the tensioners: unless I can see and feel something happening, I don't believe it's working. Therefore, I can't use the SM method.

[cross]

I've tried measuring with lobes pointing completely away from the bucket and i do get slightly higher reading on some, (maybe 0.01) but i find it more difficult to align bottom to the center of the bucket. If the valves were flat instead of on an angle it would been easier though.
With Honda instructions i find it much easier to align the lobe over the bucket as you can see bucket compressing and when it stops, you are good. Plus it only takes 4 repositioning to check all.
But when you really think about it, valve gap should be in 0.06mm-0.13mm range and every which way we do it, we would not be off more then 0.01/0.02 which is not a big deal.
I've helped friend once adjust his cb900f valves and have done bunch of valve adjusting on older fiats and alfas and they both have similar shim over bucket setup but different lobe position for measuring per manufacturer.

Having done many repairs on my and friends cars since i was a teenager (out of a hobby) i should be having more confidence in projects like this so i do appreciate all the opinions and help!
This club rocks!