Noisy valves after adjustment

[blan 5]

Inspecting the value clearances I discovered that the cylinders had been miss-identified at some point in the bikes life. Correct iD being cylinder #1 on left of engine as you sit on the bike as per the maintenance manual. Also given that the bike is the NC700X not the 750 the cam sprocket #1 position marker has to be in line with the upper cylinder head marker when T1 is in line with the position notch not the lower again as per the maintenance manual, all 4 cylinder #1 valves were in contact with the rockers. After resetting the clearances to 0.17 intake and 0.28 exhaust, the bike now sounds like it has a diesel engine installed. I've recapped through the procedure several times and checked the feeler gauges several times with a micrometer and a vernier caliper and can't find any mistakes but it ticks loudly like Hell now.  Performance wise the bike runs like a dream and has gained power, climbing hill's in gears it could never of done in before. Once the bike is hot the valve noise quietens to a degree but is still very much there. Has anyone experienced this before, any thoughts at all would be appreciated. I have a diesel engined bike andbits embarrassing.

[Scootabout 2,263]

At the risk of sounding facetious, people often describe the NC engine as being like a diesel. Usually they mean in the sense of high torque at low revs. As for ticking, I don't remember that being an issue on my 700X.  

 

[Slowboy 20,528]

I hope it doesn’t disappoint, but this noise is normal for an NC, it can sound like a knitting machine at max chat. The upside of this is it’ll keep on keeping on for well over 150,000 miles, (the record on here is over 250,000 miles with normal servicing).

Edited September 4, 2022 by slowboy

[shiggsy 529]

I believe there was a version of the manual which had incorrect instructions on how to line up the cylinders. Probably worth doing some valve adjustment searches on here.

[trisaki 2,029]

1 hour ago, shiggsy said:

I believe there was a version of the manual which had incorrect instructions on how to line up the cylinders. Probably worth doing some valve adjustment searches on here.

It's called  you tube 

[trisaki 2,029]

15 hours ago, blan said:

Inspecting the value clearances I discovered that the cylinders had been miss-identified at some point in the bikes life. Correct iD being cylinder #1 on left of engine as you sit on the bike as per the maintenance manual. Also given that the bike is the NC700X not the 750 the cam sprocket #1 position marker has to be in line with the upper cylinder head marker when T1 is in line with the position notch not the lower again as per the maintenance manual, all 4 cylinder #1 valves were in contact with the rockers. After resetting the clearances to 0.17 intake and 0.28 exhaust, the bike now sounds like it has a diesel engine installed. I've recapped through the procedure several times and checked the feeler gauges several times with a micrometer and a vernier caliper and can't find any mistakes but it ticks loudly like Hell now.  Performance wise the bike runs like a dream and has gained power, climbing hill's in gears it could never of done in before. Once the bike is hot the valve noise quietens to a degree but is still very much there. Has anyone experienced this before, any thoughts at all would be appreciated. I have a diesel engined bike andbits embarrassing.

If anywhere near Sussex pop it down to my wshop near Arundel and I would  have a listen etc  and also  compare with my own 

[Grumpy old man 4,682]

Yep! Had mine out without the helmet or ear plugs today and there's a lot of valve clatter.

Invest in some good ear plugs.

[blan 5]

9 hours ago, trisaki said:

If anywhere near Sussex pop it down to my wshop near Arundel and I would  have a listen etc  and also  compare with my own 

Cheers for the offer but I'm almost 180 miles from you, thanks though 

[Slowboy 20,528]

Here we are

 

Hope that helps

[Davidogilvie 3]

I do have a question about the valve clearance in the video shows the marks on the centre side of bike which mines doesnt have..but does have t1 and t2 marks so can line them up..after adjusting the valves there is movement in the arms is this normal..cos i do hate having the tinging noise..

[Andy m 23,584]

At 5:50 or so he shows the engine at TDC with the valves all closed. At this point there MUST be free play between the valve and rocker. This is what you are setting.

 

If you remove all clearance, no tapping, the valve will never fully close when the engine is hot and you will enter a world of pain. At best the compression is low and it overheats,  at worst the piston comes up and ****s the valve, dumping a load of shrapnel down the bore.

 

It's probably better to set the gap big than small, more tapping. This will only cause a bit of wear by vibration.

 

Not sure what you mean by marks on the centre of the bike? If the T1 mark can be seen and the rockers can be felt to rock you are there. Another half degree doesn't matter. If there is zero gap you either turn it a full turn, wait for it to cool properly (overnight) or try and work out what's broken.

 

Andy

Edited May 5, 2023 by Andy m

[blan 5]

After my initial post at the beginning of this thread ans now having run the bike almost every day I can say the valve clatter is very normal, not detrimental to the performance of the engine in any way and should be embraced as a personality trait of the NC. Since the valves were reset correctly my bike goes like the wind and the clatter becomes a roar at speed !

[steeve139 98]

Hi,  This is all a bit worrying.  I am about to pay a professional wrench a few hundred pounds to set my valve clearances, and I don't want valves tapping to be what I hear.

 

The valve clearances have a plus and a minus tolerance - so there will be a gap.  The valve clearances have to be set when the engine is cold (at least in the book), so we can expect a difference in the noise between when the engine is cold and warm.

 

Any valve noise has to be the result of two pieces of metal hitting each other.  Loud valve noise must be the result of two pieces of metal hitting each other hard.  We would have to expect wear to be the result of loud repetitive noises.

 

I'll be hoping for my tappet noise when the engine is cold to diminish.  And I'll be hoping that my tappets remain inaudible to my old ears, when the engine is warm.

 

I am hoping that the valves won't require any further adjustment after the first major service.  Would anyone like to comment on that expectation?  Did your valves need adjustment at 32k miles?

[Andy m 23,584]

Don't worry.

 

Aesthetically pleasing noises are not part of the spec. You set the gap. If the owner then decides they don't like it, hard chips. These engines last 100000 miles to the factory settings. Changing specs because someone thinks blue oil is pretty or the tappety tap noise is offensive, or the bores need polish to stop dirt sticking or the 101 daft things shiney bike owners want is simply bad practice. If the noise offends and you've seen them set correctly,the best solution is ear plugs.

 

I would not expect to adjust every valve every 32000 miles. I would however expect to check them and typically find a pair that are out. If the bike was new to me and they were all out, then you'd suspect the last person to have the cover off had decided to re-write the book.

 

Andy

[Xactly 5,435]

I don’t think you need be concerned at all, other than spending a lot of money for what is a simple diy task. These engines are noted for their longevity and I don’t recall a single thread about valve replacement or burnt valve seats, just a few about an error in the workshop manual about which cylinder is which - easily determined anyway by a competent mechanic, professional or amateur. The fact is that these engines are slow-revving and as such the wear on the valve train is not high. I can’t say that valve noise was high on my NC, certainly less than the clutch rattle (mine was a manual). I sold mine before it reached 32k miles but the reason there is adjustment to the valve train is because, even set correctly, the rocker has to make contact with the valve stem tip to open the valve. This wear plus valve seat recession is why adjustment is occasionally necessary. That said the geometry of the NC valve train is good, allowing the rocker to push down straight on the valve stem, minimising side thrust, which causes wear in the valve guides (ask any Meriden Triumph twin owner). In short, if the valves are adjusted correctly they are likely to stay in adjustment for long periods but not indefinitely.

[MatBin 5,097]

Mine is at 12k miles, the valves are not at all noisy even when not wearing a lid. This morning I changed the oil so ran the engine for a little while and I would say the valves are some of the quietest I have known on a bike, I have never adjusted them since I bought the bike 3 years ago second hand, what happened before I purchased the bike I can't say.

[Xactly 5,435]

Mine were the same, though I adjusted them myself when new to get an accurate wear start point. Waste of time really as I sold it before I fell off it with boredom. Handy for the next owner though....