Low rattle on cold start.

shahyaan_imp

Running like a top
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Heya

Is it normal for the CB to rattle a tad bit when cold? This engine is so smooth and quiet compared with my Harley. I’m guessing it’s the valve clearance that then shrinks when warm.


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At 1,000rpm at idle, a given valve will cycle open and closed at just over 8 times per second (8 & 1/3 Hz, or approx every 1/8th of a second). If the clearance is too loose or there is insufficient oil pressure for some reason, the valve will click.

Find yourself an engine stethoscope and see if you can identify the area the sound is coming from.

Between the injectors, valves, and all the moving bits, including external stuff like the PAIR valve, there are plenty of sources for minor ticking.
 
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LakeWylieJoe_imp said:
At 1,000rpm at idle, a given valve will cycle open and closed at just over 8 times per second (8 & 1/3 Hz, or approx every 1/8th of a second). If the clearance is too loose or there is insufficient oil pressure for some reason, the valve will click.

Find yourself an engine stethoscope and see if you can identify the area the sound is coming from.

Between the injectors, valves, and all the moving bits, including external stuff like the PAIR valve, there are plenty of sources for minor ticking.

This is usually during the warm up phase so idle is higher. Once the bike is warm I don’t notice it.


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I don't believe it is normal, though whatever it is, it might not be harmful. A valve with too much lash might tick, but likely not "rattle." The advice above to use a stethoscope when it is cold and making noise is sound advice.
 
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apex1_imp said:
I don't believe it is normal, though whatever it is, it might not be harmful. A valve with too much lash might tick, but likely not "rattle." The advice above to use a stethoscope when it is cold and making noise is sound advice.

I guess it could be described as a ticking. That’s a better choice of words over rattle.


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My engine has 35,000+ miles on it. The valves are all center of spec range (checked and adjusted every 8,000). My engine has no ticking at all when I first fire it up cold. It develops little ticks from several places as it warms up. I attribute this to the oil (Honda GN4 10W-30) getting thinner with the heat. It's done this since brand new. All the noises are quite subtle, though.
 
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LakeWylieJoe_imp said:
My engine has 35,000+ miles on it. The valves are all center of spec range (checked and adjusted every 8,000). My engine has no ticking at all when I first fire it up cold. It develops little ticks from several places as it warms up. I attribute this to the oil (Honda GN4 10W-30) getting thinner with the heat. It's done this since brand new. All the noises are quite subtle, though.

Ok looks like I’ll need to investigate.


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LakeWylieJoe_imp said:
My engine has 35,000+ miles on it. The valves are all center of spec range (checked and adjusted every 8,000). My engine has no ticking at all when I first fire it up cold. It develops little ticks from several places as it warms up. I attribute this to the oil (Honda GN4 10W-30) getting thinner with the heat. It's done this since brand new. All the noises are quite subtle, though.
Based on my experience, I generally concur.
 
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Actually now I read it in detail. It could be oil as well. Oil is a bit old from previous owner not using it much. I was planing on doing a quick oil change.

I’ll have to decide on the ideal choice for this bike. At the risk of starting another oil debate may go semi synth within the temperature range for my location.


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shahyaan_imp said:
Actually now I read it in detail. It could be oil as well. Oil is a bit old from previous owner not using it much. I was planing on doing a quick oil change.

I’ll have to decide on the ideal choice for this bike. At the risk of starting another oil debate may go semi synth within the temperature range for my location.


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I always used 10W40, and initially Honda GN4. I changed to semi and then full synthetic and the engine was quieter and clutch [even more] buttery.


(I think the statement covers much of the oil genre.)
 
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GoldOxide_imp said:
shahyaan_imp said:
Actually now I read it in detail. It could be oil as well. Oil is a bit old from previous owner not using it much. I was planing on doing a quick oil change.

I’ll have to decide on the ideal choice for this bike. At the risk of starting another oil debate may go semi synth within the temperature range for my location.


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I always used 10W40, and initially Honda GN4. I changed to semi and then full synthetic and the engine was quieter and clutch [even more] buttery.


(I think the statement covers much of the oil genre.)
I always used 10W40, and initially Honda GN4. I changed to semi and then full synthetic and the engine was quieter and clutch [even more] buttery.


(I think the statement covers much of the oil genre.)

That’s perfect. I like making a choice based on experience with. I’ll grab the oil as it’s needed and cheap.


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My bike has now done over 130,000 kms. I now find that, as the engine gets hotter, the gearbox gets stiffer. It shifts fine when under way, but finding first and neutral is tough at a standstill or low revs.
 
Cormanus_imp said:
My bike has now done over 130,000 kms. I now find that, as the engine gets hotter, the gearbox gets stiffer. It shifts fine when under way, but finding first and neutral is tough at a standstill or low revs.
Makes the bike harder to steal when you leave it running. :)
 
hadn't thought of that, GO. I should've been clearer: it's hard to get the bike out of 1st or 2nd and into neutral when it's hot. Goes in all right.
 
Cormanus_imp said:
hadn't thought of that, GO. I should've been clearer: it's hard to get the bike out of 1st or 2nd and into neutral when it's hot. Goes in all right.
Ah, okay. An annoying ownership distraction then, but partially tempered by the 130000+ kms of love.
 
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I can’t seem to get the GN4 oil here in the UK. Any preference with Castrol or Motul?


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I've nearly always used Castrol, it's easy to get hold of (Halfords for a start) and is a quality brand. If you Google reviews there's so many owners that use it and I couldn't find any negatives last time I researched it. Put it this way I will be using it again in my CB.
 
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Jfro5687_imp said:
I've nearly always used Castrol, it's easy to get hold of (Halfords for a start) and is a quality brand. If you Google reviews there's so many owners that use it and I couldn't find any negatives last time I researched it. Put it this way I will be using it again in my CB.

That’s what I was hoping. Euro Carparts doing 50% off the motorcycle fully synth version.


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Houtman_imp said:
I have always used the Mobil 1 synthetic motorcycle oils in my bikes , is this available in the UK ?

I think Mobil 1 is available. Though didn’t see it in my searches when filtering for CB requirements.


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