Did the 8000 mile valve clearance check/adjustment

The weather was very nice on March 14th in the far South Chicagoland suburbs. I decided to ready my motos.

I followed the How to written by Antarius in the how to section. Very well written with photos. The hardest part is removing the radiator and all that clips to it in the back.

My valves were all tight. one of the exhaust valves was .003th of an inch tight (.0762mm) Exhaust more out of spec than intake. I used my Honda valve adjustment/10mm locknut combo unit to quickly adjust the valves. That tool is awesome! I refilled the radiator with Honda/Acura Type II premixed blue coolant, Just as I have done with my 2011 125cc PCX. Oil changed @ 300 miles, then again at 3000 miles. And now I will do 5,000 mile OCI

Some photos:





I am going to check the valves again in 8,000 miles (16,000 odometer). Upping the interval if nothing moves. I general ride around in D mode on my DCT. I rarely give full throttle. I enjoy cruising, and moderately accelerating. These 8,000 miles consisted of every type of riding though, including two, four hour highway riding at 75mph. (4,000+ rpm for hours)

What is this "Honda valve adjustment/10mm locknut combo unit " you speak of?

bamamate said:

What is this "Honda valve adjustment/10mm locknut combo unit " you speak of?

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Is that tool made by Honda, or available at Honda Dealers? Do you have a part number or item number or manufacturer for this tool? Thanks

I don't have the official "jam nut" tool from Honda, 7 years ago it was priced above 150 bucks. I picked this one up:

http://www.amazon.com/Alltrade-648827-2-Inch-Valve-Adjustment/dp/B0002Q8TU0


It is called a Jam Nut Valve Adjustment Tool. The screwdriver is spring resisted in inside the half cut away 10mm socket, so the screwdriver stays up, or down, however you need it to be during the adjustment. And the cut out from the socket makes lining up the screwdriver easy. All this really does is save space and time, by combing the two into one, and allows you to hold the set screw in place as you torque down the nut.

That's a nifty tool...... thanks for the post..... Add this to my list......

I suppose if you DIDN'T already have a 10mm box wrench and a standard screwdriver, then this WOULD be a cool tool.

Just curious, were any of the clearances within spec despite being on the tight side ?

The Honda wrench is p/n 07708-0030200.

It's a 10 mm box end with a very long handle and deep offset which allows it to get over things such as the rocker arm stands. The long handle is not to put additional leverage on the nut but to keep your hand clear of obstructions. It lacks an integral screwdriver but it works fine for me and it's the same tool used for motorcycle and autos.

I've had for one years and I can't recall what I paid but Partzilla.com has it for $4+.

I am going to check the valves again in 16,000 miles

You checked them at 8k and they were all tight, yet you're going to double that and check at an interval twice as long? Or are you going to check again when you hit 16k on the odometer? Since they were tight at 8k I would check again at the same interval and not double it. Maybe I misunderstood you.

Griff said:

Just curious, were any of the clearances within spec despite being on the tight side ?

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Yes, all of the intake valves on the very end of tight spec. .001 of an inch.

The exhaust side were all .002-.003 of an inch tight.

Todd L. said:

I am going to check the valves again in 16,000 miles

You checked them at 8k and they were all tight, yet you're going to double that and check at an interval twice as long? Or are you going to check again when you hit 16k on the odometer? Since they were tight at 8k I would check again at the same interval and not double it. Maybe I misunderstood you.

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next valve check @ 16,000 miles on the odometer, sorry I worded that wrong. Then I'll compare notes and see if the valves held within spec. Working my way up to and past the 16k interval the nc750 has in Europe.

I have a 2011 honda PCX 125cc that the manual says check the valves every 2,500 miles, and change the oil every 5,000. YEAH CHECK VALVES MORE THAN OIL CHANGES!!! And to get to the valves you have to dismantle 60% of the scooter.

I checked them at the 600, and then at 3000, and again at 5500. At 600 I had to adjust them back into spec (slightly tight). But at checks 3k, and 5k, no movement at all from what I set them to. I'm now at 13,000 miles on the PCX and won't be checking the valves until 20,000 (15,000 mile valve check interval) If they don't move I'll up it to 20,000, and every time I check and no movement up another 5k, until I find the real interval to use.

I plan on doing the same with the NC700X. Check again at the proper stated mileage interval 8k, then add 5k each time the valves don't move.

OriginalRocket said:

Yes, all of the intake valves on the very end of tight spec. .001 of an inch.

The exhaust side were all .002-.003 of an inch tight.

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Thanks for that.

When I did my 2013's valves they were all in spec but I went ahead and adjusted each valve to be exactly to the middle of their clearance specs. The only thing I found out of spec were feeler gauges. Strangest thing ever for me as prior to adjusting my valves, on a whim, I went ahead and put a micrometer on all of my gauges and found 2 of my 5 sets were not accurate! In fact they were off a lot though I forget the actual values.

I went ahead and took all of my gauges and my micrometer to the nearest Advance Auto Parts store and used their micrometer to double check my findings and their gauge confirmed my readings. Then the store manager and I checked 4 sets of gauges they had in stock and only one set had a 100% accurate set of blades! I bought that set. Check your gauges before you check your valves people. Only one of the 12 or so inaccurate blades had enough use to consider wear as a factor and the fact new gauge sets sitting on the shelf are out of spec is quite disconcerting.

Like we need more work in our lives.

OriginalRocket said:

Yes, all of the intake valves on the very end of tight spec. .001 of an inch.

The exhaust side were all .002-.003 of an inch tight.

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Good Thread. I worked as a wrench for vw in the early 70s. Adjusted a lot of valves. The early 70s vw vans ate exhaust valves. You need to get to know the motor but most modern day mc motors are easy on intake valves. The spec above for intake is perfect for performance and I would not have touched them. Exhaust I always try to leave on the fat side of the spec.

Good advice on the exhaust valves. The little bit longer they stay on the seat the more heat transfers from the valve to the seat where it can be transferred to the cooling system. Intake valves have a slightly easier life. Modern engines generally have very durable

So. Another data point on the 8000 mile valve adjustments.
The younger son and I did the 8000 mi. service on his 2012 NC. The valves were all just a little tight. Only on a couple intake could we not get the feeler gauge in though.
I also adjust valves to err on the loose side.

On the NC700, do the valves ALWAYS go out of adjustment in a single direction or can they get tighter OR looser ?
If so, why would some tighten and others loosen. What would cause that difference?

BerndM said:

On the NC700, do the valves ALWAYS go out of adjustment in a single direction or can they get tighter OR looser ?
If so, why would some tighten and others loosen. What would cause that difference?

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Valves can loosen over time from wear on the valve tip, adjuster tip, the cam itself. It is also possible to insufficiently torque the locknut. It is further possible that they were not correctly set the last time. Clearances can change as you torque the locknut or the clearance could have been adjusted wrong, or at the wrong valve timing. When I have finished adjusting valves, I always rotate the engine a couple of revolutions in the direction of normal rotation and check them again. Normally they are fine, but I have had a few occasions when a valve needed to be re-clearanced. The valves tighten when they recede, or 'sink' into the seats, especially the exhaust valves. Unless there is some kind of mechanical problem going on like lubrication failure or moving locknuts, recession is generally much more than valve train wear and most times they are getting tighter. Since tighter valves are quieter than loose valves, that is why you can't just listen for noisy valves to determine when it is time to adjust them. Tight valves are generally more dangerous to engine health than loose valves. Valves are cooled by time in contact with the valve seat which becomes less as the clearance is reduced. At the point of negative clearance (possible as the engine heats up) there is actually exhaust gas flowing through the supposedly closed valve which heats it up to the point of failure.

If an engine is loose one time and tight the next, I would look at technique as the most likely cause.

Checked mine at 22k miles, 1 valve little too tight , one little loose.

Thanks antarius.

Valve Adjustment Step-By-Step

Thanks for the picture and findings, to add to the collective group's information