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+--- Thread: Low rattle on cold start. (/showthread.php?tid=4694)
Low rattle on cold start. - shahyaan_imp - 11-09-2020
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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RE: Low rattle on cold start. - LakeWylieJoe_imp - 11-09-2020
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.
Low rattle on cold start. - shahyaan_imp - 11-09-2020
(11-09-2020, 02:56 AM)LakeWylieJoe_imp Wrote: 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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RE: Low rattle on cold start. - apex1_imp - 11-09-2020
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.
Low rattle on cold start. - shahyaan_imp - 11-10-2020
(11-09-2020, 09:52 PM)apex1_imp Wrote: 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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RE: Low rattle on cold start. - LakeWylieJoe_imp - 11-10-2020
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.
Low rattle on cold start. - shahyaan_imp - 11-10-2020
(11-10-2020, 02:55 AM)LakeWylieJoe_imp Wrote: 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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RE: Low rattle on cold start. - GoldOxide_imp - 11-10-2020
(11-10-2020, 02:55 AM)LakeWylieJoe_imp Wrote: 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.
Low rattle on cold start. - shahyaan_imp - 11-10-2020
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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RE: Low rattle on cold start. - GoldOxide_imp - 11-10-2020
(11-10-2020, 03:41 AM)shahyaan_imp Wrote: 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.)