Valve Adjustment Step-By-Step

[b_rubenstein]

With insufficient valve clearance the valves will not fully seat and give a gas tight seal. This results in a loss of engine compression which decreases engine power, and makes it harder to start. This also prevents the valves from properly cooling by transferring heat by conduction into the cylinder head. This is particularly true for the exhaust valves, and if run long enough without being able to fully seat cause the edge if the valve to melt. Even with the NC's very low state of tune, never adjusting the valves over 60k miles would almost certainly damage it.

 

[rmezei]

With insufficient valve clearance the valves will not fully seat and give a gas tight seal. This results in a loss of engine compression which decreases engine power, and makes it harder to start. This also prevents the valves from properly cooling by transferring heat by conduction into the cylinder head. This is particularly true for the exhaust valves, and if run long enough without being able to fully seat cause the edge if the valve to melt. Even with the NC's very low state of tune, never adjusting the valves over 60k miles would almost certainly damage it.

thanks for the input - what I hate doing is opening up an engine to adjust and check things just for fun - i am not that kind of person... I like to approach things proactively but not by poking things that run fine, especially engines... now I understand this is not something you can see it coming so I may just put it off to 40K to check them (40000 KM - not miles) and then again at 80000 KM depending on what I find - guess I probably should eventually 'inspect them'.

 

[b_rubenstein]

FWIW, I checked the valves around every 8k miles. The first time I had to actually make any valve adjustments was at 21,500 miles (35k KM) when two exhaust valves were out by +0.001". 40k KM should be okay.

 

[dduelin]

I don't think Honda recommends service intervals based on the fun factor involved. Service recommendations are based on reasonable data derived over many years and they don't really care if the dealer does the work or not so forget the "it's all about the dealer making money".

Maintenance is based on reasonable expectations of use and analysis. I personally think that Honda errs on the conservative side so owners can neglect maintenance and not affect their [Honda] hard-earned reputation for long service.

 

[showkey]

With insufficient valve clearance the valves will not fully seat and give a gas tight seal. This results in a loss of engine compression which decreases engine power, and makes it harder to start. This also prevents the valves from properly cooling by transferring heat by conduction into the cylinder head. This is particularly true for the exhaust valves, and if run long enough without being able to fully seat cause the edge if the valve to melt. Even with the NC's very low state of tune, never adjusting the valves over 60k miles would almost certainly damage it.

Not saying don’t check the valves in your NC............but..............
Then there is the thought that similar parts and similar engine design running in several million Honda cars and trucks have the first valve set interval at 105,000 miles.

 

[b_rubenstein]

I have a 2011 CR-V and the manual recommends checking the valves at 100,000 miles if they are making noise. Keep in mind that the CR-V is turning at less than 3,000 RPM at 75 MPH and the NC is spinning a lot faster at that speed. There are real reasons why Honda call for checking valves on the NC at 16,000 mile intervals and 4 wheel vehicles at 100,000 miles. EPA regulations probably come into play here also. Vehicles have to be able to meet their pollution numbers with minimal maintenance at 100,000 miles. This is why spark plugs aren't required to be changed before 100,000 miles.

 

[showkey]

It actually just the opposite on plugs and valve adjustment and other components. They know that the vehicle will pass emissions without plugs or valve adjustment. If they did effect emissions they would have replacement or service intervals at numbers of years past like 60,000 miles for plugs, valve adjust, O2 sensors.

 

[670cc]

It seems screw and locknut valve systems like on the NC, although easier to adjust, require more attention. My GL1800 (shim adjust) passed the 32,000 and 64,000 mile valve checks with no adjustment required. Next check is at 96,000 miles. My 4 cylinder car engine recommends the first check at 120,000 miles. The NC would have seen 7 valve checks by then (15 by the old 8000 mile standard). That’s just too maintenance intensive.

I sometimes wish the NC had a shim adjust valve system because them seem to require much less attention. My CRF250L uses shims. It will be interesting to see how much adjustment is needed over time, if any.

On the other hand, if we’re willing to put up with drive chain maintenance, 16,000 mile valve check intervals is nothing.

 

[b_rubenstein]

If they did effect emissions they would have replacement or service intervals at numbers of years past like 60,000 miles for plugs, valve adjust, O2 sensors.

Those are all things that fall under Emission System, and are required to keep emissions within limits for 100,000 miles without maintenance.

 

[TJW]

Hi guys,

I'm in the middle of checking the valves on my 2012 NC700X and having read the thread, another step-by-step guide and watched the video (which I think is spectacular) I can't help but say that I am properly confused by which cylinder is 1 and which is 2.

As per what it says on here cylinder 1 is on the left side (when sitting on the bike) or the clutch-lever side and cylinder 2 is on the right or the throttle side.

However, when I align the flywheel to 1T I can easily wriggle the 4 tappets (2x inlet/top and 2x outlet/bottom) above the right (throttle side) cylinder and the mark for the "cylinder 1" points upwards (to the opening of cylinder head/front of bike) in the inspection hole on the throttle side of the cylinder head.

Again, when I align the flywheel to 2T I can wriggle the 4 tappets above the left (clutch lever side) cylinder and the mark for "cylinder 2" points upwards (to the opening of the cylinder head/front of the bike) in the inspection hole on the throttle side of the cylinder head.

So basically it's exactly opposite to what's been said in this forum.

If I do it the way I described it above the most of valves are within specification whilst some need adjusting, which I would expect after 10,000 miles. If I do it the way it's been described on this forum (although I can't get the marks to align with the bottom notch on the inspection hole on the throttle side) basically all valves are way too tight.

Now, I know it sounds crazy, but can it be that European bikes (such as mine) are exact opposite to American bikes when it comes to which cylinder is 1 and which is cylinder 2 ??????

Also, am I right in saying that it would makes sense that if the European cylinders are opposite (1=right and 2=left) we need to align the marks with the "top" as compared to the "bottom" when 1=left and 2=right ????

Any thoughts, anybody?

Cheers
TJW

 

[lootzyan]

Are you adjusting valves based on instruction in 2012 Service Manual non-US edition? There is a known error.
This is a correct instruction:

 

[670cc]

Cylinder 1 is on the clutch lever side on all NC engines across the world.

After the first time I adjusted the valves, I’ve totally ignored the camshaft inspection plug. I don’t even take the cap off as it’s a waste of time.

What I’d suggest is to keep it simple. Align the crankshaft 1T mark. Wiggle the clutch lever side rocker arms. Turn the crank 360 degrees and again align the 1T mark. Attempt to wiggle the rocker arms. Whichever of these two positions has slack or the most slack is the top of the compression stroke and is the position where you want to adjust the valves. The position 360 degrees from this is the end of the exhaust stroke/beginning of intake stroke, so it is not the valve adjust position.

When that is done, repeat the process on the throttle grip side using the 2T mark.

Remember that it’s a 270 degree crank so the relationship between the two cylinders at any given point are not exact opposite. Just treat them independently and ignore the other.

I vaguely recall there was some early misinformation about the position of the camshaft mark. My Honda Service manual says that when crankshaft 1T is aligned, and camshaft 1 mark is pointing down toward the cylinder base mark, that is your cylinder one adjustment position.

 

[TJW]

Cylinder 1 is on the clutch lever side on all NC engines across the world.

Align the crankshaft 1T mark. Wiggle the clutch lever side rocker arms. Turn the crank 360 degrees and again align the 1T mark. Attempt to wiggle the rocker arms. Whichever of these two positions has slack or the most slack is the top of the compression stroke and is the position where you want to adjust the valves.



Thanks a lot for your quick reply.

I did exactly that: I aligned the crankshaft to the 1T mark on the flywheel but instead of the tappets above the LEFT (clutch lever side) cylinder - which should be cylinder 1 - the tappets above the RIGHT (throttle side) cylinder - which should be cylinder 2 - have slack. When I align the crankshaft to the 2T mark on the flywheel the tappets above the LEFT cylinder (which should be cylinder 1) have slack.

It doesn't really matter which notch (top or bottom) the 1 or 2 marks align as I can't get them to face the opposite way anyway.

 

[TJW]

Thanks for your quick reply.

Indeed my manual says the exact opposite. I'll check tomorrow what version my manual is.

 

[670cc]

Thanks a lot for your quick reply.

I did exactly that: I aligned the crankshaft to the 1T mark on the flywheel but instead of the tappets above the LEFT (clutch lever side) cylinder - which should be cylinder 1 - the tappets above the RIGHT (throttle side) cylinder - which should be cylinder 2 - have slack. When I align the crankshaft to the 2T mark on the flywheel the tappets above the LEFT cylinder (which should be cylinder 1) have slack.

It doesn't really matter which notch (top or bottom) the 1 or 2 marks align as I can't get them to face the opposite way anyway.

You did not mention trying the crankshaft 1T in two successive revolution positions. Forget about the 2T mark for a moment and forget about the camshaft indicator for a moment, and forget about cylinder 2. Try positioning the crankshaft at 1T mark, and if the clutch lever side cylinder 1 rockers are not loose, rotate the crankshaft one full turn to again be at 1T, and the rockers should be loose on the clutch lever side, cylinder 1. Understand that the crank goes around twice per camshaft revolution, so there are two different valve positions correndsponding to the 1T crankshaft mark.

When you do find the 1T position that has loose rockers, you should also find that the camshaft 1 indicator is pointing toward the cylinder base, or rearward, per post #191 above.

I think you got off on the wrong track because you have consulted the misprinted manual.

 

[TJW]

Are you adjusting valves based on instruction in 2012 Service Manual non-US edition? There is a known error.
This is a correct instruction:

View attachment 37246

View attachment 37248

Thanks a lot for that, I shall check what version my manual is.

 

[TJW]

You did not mention trying the crankshaft 1T in two successive revolution positions. Forget about the 2T mark for a moment and forget about the camshaft indicator for a moment, and forget about cylinder 2. Try positioning the crankshaft at 1T mark, and if the clutch lever side cylinder 1 rockers are not loose, rotate the crankshaft one full turn to again be at 1T, and the rockers should be loose on the clutch lever side, cylinder 1. Understand that the crank goes around twice per camshaft revolution, so there are two different valve positions correndsponding to the 1T crankshaft mark.

When you do find the 1T position that has loose rockers, you should also find that the camshaft 1 indicator is pointing toward the cylinder base, or rearward, per post #191 above.

I think you got off on the wrong track because you have consulted the misprinted manual.

Thank you very much indeed. I won't have time today or tomorrow, but will give it a try on Monday.

 

[TJW]

Thank you very much indeed. I won't have time today or tomorrow, but will give it a try on Monday.

Dear All,

I've had another look at things today and indeed, thanks to your kind help, it looks as if I got a grip on things now.

Just to clarify:

- When I turn the crankshaft counter-clockwise to align the 1T mark on the flywheel (so the mark for cylinder 1 lines up with the 'bottom' notch of the cylinder head index line) I can wriggle the 4 rocker arms of the clutch-lever side cylinder AND 2 (outlet) rocker arms of the throttle-side cylinder.

- When I turn the crankshaft counter-clockwise to align the 2T mark on the flywheel (so the mark for cylinder 2 lines up with the 'bottom' notch of the cylinder head index line) I can wriggle the 4 rocker arms of the throttle-side cylinder AND 2 of the clutch-lever side cylinder (I quite can't remember now which ones ...).

I was wondering if somebody could check the above?

I haven't had a chance to put it all together as I've given the radiator to a company for refurbishment.

Thanks a lot for your help.

TJW

 

[lootzyan]

Just concentrate on one cylinder at a time. Don't worry about other cylinder.

 

[670cc]

Ditto the above. It’s irrelevant what is loose on the other cylinder. Just be concerned about the valves for the cylinder you are adjusting. And again, understand that if you don’t happen to find the four rocker arms loose as expected when you’re on the crankshaft T mark for the cylinder that you’re working with, just rotate the crank one full turn and then you will be at the valve adjustment position.