Valve Adjustment Interval - 2012/13 Model Versus 2014/15 Model

[AnacortesArmyGuy]

I noticed in the service manual that 2012/13 model years have a valve clearance inspection as part of the 8,000 service, but for the 2014/15 model years it's not performed until the 16,000 mile service. Is anyone aware of some change to the engine that would cause Honda to make this change? I ask because I'm taking my 2012 in for it's 8,000 service next week, and I'm sure the valve check will be a hefty piece of the overall 8,000 mile service charge. The service manager mentioned when I set up the appointment that it's rare that they find a bike needing it's valves adjusted at the 8,000 mile service, which makes me think that Honda realized the bike did not need the valves checked at 8,000 miles, thus modifying the maintenance schedule for the 2014/15 model years. My bike is running great - great gas mileage, starts right up, and gives no indication the valves are out of adjustment. What do other forum members think?

 

[T S N]

My 2015 manual says to check/adjust every 8000 miles.

 

[ld_rider]

My 2014 <Factory> manual says check/adjust every 16,000 miles

 

[hojo]

No clue why the difference, but my "2012-2014" OEM manual says that for models 'after 2013', inspect valves at 16,000 miles.

 

[Juggler]

Is anyone aware of some change to the engine that would cause Honda to make this change?

Try to compare partnumbers on "old" and "new" versions. If they are the same I see only one reason - honda could change alloy/composition with same p/n, but it is rarely the case.
And btw, in EU there is the same situation - 700 models 12000km valves check, 750 models (no new 2014+ 700 models, they switched all versions to 745 engine) 24000 valves check. Maybe new 700 US models got upgraded valves from 745 engine?

 

[glencoeman]

Manufacturers tend to be more cautious when they introduce a bike with a completely new engine onto the market place. I think that is why early bikes had a 8000 mile valve check and then changed to 16000 mile check after it became clear that the 8000 mile check was not really necessary. Having said that, I will probably do my valve check at 8000 miles as I can change the coolant at the same time when I remove the radiator - makes more sense to me. I have only done 6500 miles in three years as I own a couple more bikes to play with.

 

[Deleted member 1183]

Manufacturers tend to be more cautious when they introduce a bike with a completely new engine onto the market place. I think that is why early bikes had a 8000 mile valve check and then changed to 16000 mile check after it became clear that the 8000 mile check was not really necessary. Having said that, I will probably do my valve check at 8000 miles as I can change the coolant at the same time when I remove the radiator - makes more sense to me. I have only done 6500 miles in three years as I own a couple more bikes to play with.

I agree with this assessment. I have been consistently lazy with first valve clearance checks on Hondas in general. My first check of my GL1800 was done at 38.000 miles and all was within spec. However the NC has a very different valve operation system which is also very new, and I decided I would not allow matters to outstand for that long. Folks doing the check at 8000 miles reported a slight tightness on the exhaust valve clearances in particular. However my understanding was that even then the clearances were just within spec or barely outside it.

Moving on to my own bike, I checked the clearances for the first time a few days ago at 17000 miles. The clearances on almost all the valves were a little tight, and slightly outside of spec, especially the exhaust valves. I needed an adjustment of between 2 and 3 thousands of an inch to set them on the loose side of spec. I probably could have gotten away with less, but the method of adjustment is very basic, and it will never be exactly right due to the wear pattern between the tip of the adjuster screw and the head of the valve stem. However there was still a substantial clearance remaining prior to the adjustment that I could feel manually without feeler guages, and there was no sign whatsoever that the tight clearances were a problem. The engine is running exactly the same after as before, albeit with a slightly louder rustle off the valves.

To summarise, I believed it would be ok to leave checking for 17000 miles, and I did so with no ill affects to the motorcycle. I would only do this with a Honda and under no circumstances would I do it with my KTM or indeed any European motorcycle.

 

[Old Can Ride]

I noticed in the service manual that 2012/13 model years have a valve clearance inspection as part of the 8,000 service, but for the 2014/15 model years it's not performed until the 16,000 mile service. Is anyone aware of some change to the engine that would cause Honda to make this change? I ask because I'm taking my 2012 in for it's 8,000 service next week, and I'm sure the valve check will be a hefty piece of the overall 8,000 mile service charge. The service manager mentioned when I set up the appointment that it's rare that they find a bike needing it's valves adjusted at the 8,000 mile service, which makes me think that Honda realized the bike did not need the valves checked at 8,000 miles, thus modifying the maintenance schedule for the 2014/15 model years. My bike is running great - great gas mileage, starts right up, and gives no indication the valves are out of adjustment. What do other forum members think?

I was in Anacortes, WA all last week for my grand daughter's high school registration. Beautiful island!

 

[Ruggybuggy]

Ok here's some info for thought. I've been an auto tech over 25 years and the adjustment style we see on our NC's was very common on early Japanese vehicle. When valve adjustment were needed the car would come in with the complaint that the engine was loud with lots of ticking and was worse once the motor warmed up. I would adjust the valves and by bring the valve clearance down to spec everything was quiet again. The valve tip and tappet tip would wear quicker than the valve/seat relationship. So the question is, should this be the same situation on the NC?

 

[Ruggybuggy]

Thinking about it some more. Bucket and shim style always get tighter because the valve/seat wears faster than the cam/bucket. This would be because the valve is operation in a worse environment with heat and no oil lubrication. The tappet style wears quicker at the adjustment screw because it has a small surface area with high loads. Opinions?

 

[showkey]

Sometimes valve adjustment are often a combination of many compromises. Marketing a low maintenance long interval between services is one of those compromises. In the automotive world ( which have similar valve trains (tappet type adjusters) the valve adjustment interval has lengthened to 105,000 miles or when noisy. ( not talking about hydraulic valve train system)

Same with applies to life time coolant, 10,000-15,000 oil changes and life time trans fluid in cars. The technology has changed and so has the marketing and competition in maintenance intervals.

 

[670cc]

Same with applies to life time coolant, 10,000-15,000 oil changes and life time trans fluid in cars. The technology has changed and so has the marketing and competition in maintenance intervals.

Yes the technology has indeed changed, but it depends who's selling what. If you're selling the vehicle, oil change is at 10,000 to 15,000 miles. If you're selling oil changes, it's every 3000 miles.

 

[mreric]

dont forget that valve adjustment are subject to EPA regulation. when a manufacturer decide on that valve adjustment interval they have to submit the owners manual to the EPA for review.

 

[Deleted member 1183]

Ok here's some info for thought. I've been an auto tech over 25 years and the adjustment style we see on our NC's was very common on early Japanese vehicle. When valve adjustment were needed the car would come in with the complaint that the engine was loud with lots of ticking and was worse once the motor warmed up. I would adjust the valves and by bring the valve clearance down to spec everything was quiet again. The valve tip and tappet tip would wear quicker than the valve/seat relationship. So the question is, should this be the same situation on the NC?

I tend to agree with you and would have thought that if anything the tappets would have loosened and become noisier. However mine very gradually became quieter and I do not understand this as the rocker arm system is as old as the hills albeit Honda has reintroduced it on this bike in its latest format. Would you agree that sometimes the wear between the tips can make it difficult to get a feeler guage in, giving the impression that the valves are tight when actually they are not, but just have a slight wear groove in them ?

 

[ST13Fred]

The Accord owner's manual instructs 'adjust the valves if they are noisy', indicating a long, long interval before adjustments are necessary. My ST13 was still in tolerance at 46K miles.

 

[Old Can Ride]

In the last 20 years the metals used have gotten stronger and wear a lot less than even just a few years ago. Even Honda has extended the time intervals on the NC7 recently. Too many folks over tighten the adjustment. I would rather the adjustment be loss, than too tight.

 

[Deleted member 1183]

Don't worry. There are no tappets in NC engines. This is old, proven OHC type engine. On cam side of rocker there is a bearing - insignificant wear there. Adjuster has a half-ball tip. Every time clearance needs a correction an adjuster is turner by less than a quarter of a turn so any eventual imperfection from wear got eliminated. Adjuster should easily last 200000 (miles or km).

Nope, I aint worried, just discussing the issue with Ruggy as to why the clearances on the NC system do not increase as opposed to decrease. I am aware that the NC is a very basic system, not too dissimilar to the system on the old CB750's on which I originally learned how to do valve clearances back in the 70's. The main difference as you suggest is the bearing on the cam side. Certainly that for one will decrease the wear aspect that could contribute to loosening, leaving only the adjuster tip to wear against the valve tip. Needless to say we are only talking about the first valve check here.

Ok. Technically speaking I suppose you are correct about "no tappets". I quote from Wikipedia.......

"The term tappet is widely used in relation to internal combustion engines, but imprecisely. It is most commonly encountered as a maintenance task for overhead valve engines, that of 'adjusting the tappets'. This operation adjusts the overall clearance in the valve actuation system:"

It was from that old fashioned imprecise description that I derived the word "tappets".

 

[showkey]

^^^^^^^^***. + 2

The tappet is a general term. Often refers to the adjusting point or adjusting screw.

It is common for valves to become tighter with use. As many have stated in the past......tight is bad and is as it should be a greater concern than loose. The valves become tighter as the the valve and valve seat wears and the valve reseeds into the head slightly. Wear on the "tappets", cam followers, cam lobes , rockers arms etc is extremely slow and almost none existent. On the NC valve train there are very very few parts or points that can wear to cause excessive valve clearance in the adjustment interval. The NC is valve train is simple and precise.

 

[pismocycleguy]

The valve clearance becomes tighter with mileage instead of looser because the valve seats are being hammered by the valves beating up and down on them and this causes the valve seats to become compressed and worn and the valves to be sinking into the valve seat. So the clearance at TDC is being reduced by the valve stem moving closer to the rocker arm. That is why the valve clearances decrease and need to be adjusted so that the valves fully close at TDC.

 

[MZ5]

Ruggybuggy, I'm not sure about the theory of operation, but not only do the NC700's valves tend to wear tight rather than loose (at least during the first 30k miles or so of its life), but Honda's automotive J35 V6 exhibits the same wear pattern, and it has the same type of adjustment system as the NCX. Much later on, sometimes the J35's valves wear loose, but they wear tight initially (the first several tens of thousand of miles at least). <shrug>