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Does this sound unusual (VFR engine)

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Hyssy, May 27, 2009.

  1. This is a sound that has been bugging me for quite some time now, but never brought any concern at service time. The linked file is a 16 second recording of the engine, with the mic held just over the right hand side engine cover. You can hear when I move the mic towards the top of the cylinder, which is where the sound I am concerned about is coming from.

    It is like a rattle every half second, that's the best way I can describe it, and coming from the top of the cylinder I was wondering (and I have less mechanical experience than a bar of chocolate) if it was related to the cams.. etc.

    Anyway, if anyone could take a listen and let me know if a) I'm imagining it, b) I'm being too critical and it's a normal engine sound or c) yes, there's something I should get checked out. I would really appreciate it.


  2. Sorry, I can't offer you direct experience of these engines. But you are not imagining it, it's definitely there.

    I would guess also that you are probably right that it's related to the cams, valves or Vtec. It seems to be every second stroke (ie. once in each four-stroke cycle), so it's not likely to be a small end bush or bottom end. Can't say for sure whether it is normal or not. I would definitely get it checked out.
  3. I agree. It doesn't sound like any VFR top end noise that I have heard. Time to trundle it off to the shop, I reckon.
  4. Looking at the fisch, the way the valves operate is via a direct,non-adjustable cam-and-lifter system with resizable shims or resizable lifter. I'd imagine it's be an easy (but a shit of a) job as the cams would likely need to be removed to access the shims.

    On the both cyliner banks, the outer inlet valves are shim adjustable, while the inner pair use an adjustable lifter (I.e, you switch out for a larger lifter as it wears.)

    (The opposite is true for the exhaust valves)

    Given the nature of the sound, simple overhead construction, and the fact you were recording on the outer side, the sound you heard is the clearance between the valve lifters and the camshaft being taken up (the camshaft "slapping" the valve shim/lifter assembly tight, taking up clearance.

    There looks to be a decent amount of mass in the lifter, so I can imagine excessive clearance causing a significantly loud noise.
    Checking another source, inlet clearance is between 0.13 mm to 0.19 mm, exhaust is 0.27-0.33 mm, I can imagine as the clearances approach 0.25mm and 0.35 mm, the noise would increase significantly.

    In short, it will be fine until your next service.

    What's your service history like? When were the valves checked last?

    It is likely the valves may have been approaching their outer tolerances, however due to the cost and labour required for the job, it is likely they were doing you a favour by putting it off til next service.
    (Unless it is second hand, in which case the previous owner was likely a tightarse)

    Would it kill bike manufacturers to design engines with hydraulic lifters?!?
  5. That is one awesome reply, thanks.

    Service history is by the book. From the 1k service to 6, 12, 18 and a couple of months ago the 24k. 1, 6, 12, 24 were done at the dealer and 18 at a different dealer.

    I did ask if the valves were checked at the last service, and had a chat with the mechanic about them. They were done, and I went through the list of required jobs in the owners manual. If it is a case of the mech not wanting to do the work, well, I'll have a chat with them first and see what's what.

    This noise has not suddenly appeared though, I did notice it on and off through the time I have had the bike (since Nov 07). But now it is consistently making the sound, which is what caused the concern.

    The bike is currently at just under 26ks, so next service isn't due for a good few months yet (daily commuter). Thanks for the advice, anything else would be greatly appreciated and I'll speak to the garage tomorrow perhaps.
  6. Ok, just got back from work and recorded both sides of the engine to see if it was coming from a particular place. It seems that it's the right hand side that has the noise. The linked file starts off on the right, moves to left, then back to right again.

    You can definitely notice the difference.

    So looking at the bike, it looks like it's the rear right cylinder that is making the noise (the cylinder you can see the top of, the other half of the Vee faces forward, behind the fairing.

    Anyway, here's the file: http://files.me.com/hyssy/drf15s.aiff
  7. Ah well I dropped by the dealer today. He reckoned it was a... shim..bucket that was rattling slightly as it wasn't full of oil, possibly because I have been riding quite gently. He suggested running it in 2nd gear up to the redline to get the oil flowing.

    Like I need any encouragement to give it a run.

    Still makes the noise, not quite as loud now.... Not convinced.
  8. Sounds logical, as it heats up there would be tighter tolerances due to expansion of the metal. So that would explain the lessening sound. The question is, is it as bad when it's cold?

    I'm not sure as to the methods of lubrication, though on the fische it seems like there are drilled holes in the lifter, a bit of sludge or swarf could retard oil flow, in which case the lifters would need to be removed anyway to clean out the oil galleries.

    Also, as a long shot, the wrong thickness shim may have been installed at some stage of the bikes life, though it should have been picked up by now.

    All signs point to only one solution though
  9. Righto, it doesn't seem obvious when the engine is cold. Home again from work and it's rattling away (didn't really give it some, residential areas so I didn't want to make a racket this late).

    So cold seems to = hardly audible rattle.
  10. if its the oil, pull out the dip stick n see what colour the oil is, if its black change it, might be able to dissolve blockages those suggested is occuring
  11. The oil is 2000ks old, the last service was just over a month or so ago. So I don't think (but again with my level of knowledge I wouldn't dismiss it) that it's the cause.

    Tonight it sounded a lot worse; faster, louder.

    Link: http://files.me.com/hyssy/9hyy7l.aiff

    Engine was ~80 on the way home (cold night). Didn't really rev as late night + residential. But if anything, since revving it hard on the mechs advice has made it... worse....

    I know this is kind of posting the same crap over again, I guess I should take it to them and insist they have a look. They wont listen to the recording because unless I can replicate it on the spot, he says he can't fix it. The trouble is I've spent 3 years training to be a sound engineer so have sharper hearing than most. And he's been around loud engines for god knows how many years....

    Sigh, it's there, I can hear it, I have the recording... Any ideas?

    EDITL Oil is dark colour, but has been like that since right after the service, which did make me wonder.... as they charged me for new oil.
  12. Definitely sounds like a shim bucket and something is not opening and closing properly.
    I would definitely change the oil.
  13. VFR Noise

    Sounds more like an exhaust header leak to me. Check that the exhaust headers are tight on the motor.
  14. Not changed the oil yet but...

    Gave my dad a listen, suggested that because the sound does not increase with revs, it might be something like the cam chain tensioner... He hasn't heard it 'in the flesh' yet, will take it over tomorrow.

    Will also be taking it to the dealer to have another chat as it has gotten worse, will be pretty sure he'll hear it this time.

    Sigh, I feel like a stuck record.

    Oh and this morning the battery cranked 5 times, went clunk, the instruments went off, on again then it started but reset the clock and counters....

  15. Dealer says it's a standard running sound. Not a problem, offered to put in a thinner oil.

    I left feeling pretty confused. Explanations went from fuel injection to idle speed...

    Will get this oil changed I guess then go from there. Will probably see if I can get an opinion from another mech that could take a look...
  16. thjinner oil? i havent heard of that before...

    Generally people put in thicker oils to make it quiter not thinner
  17. I have. That sounds very much like the same solution that was proposed with the dodgy cam chain tensioner on the old CBX550. Most owners used this solution as even Honda had admitted that the design of the tensioner was sub-par and that using thinner oil would make the tensioner spring back to the correct position more effectively.

    For the record, it did actually work, although it never completely solved the problem. Most owners of CBX's just learned to live with it.

    But I confess that I have never heard of tensioners being an issue on the VFR. Of course, I have gear-driven cams in mine so I never have to worry!!!

    (Sorry, cheap anti-Origami shot there)

    :LOL: :cool:
  18. Well... I'll drag this up again. I'm pretty certain it is a cam chain tensioner issue. After doing some poking around I've come across some other riders that have identical noises which have either been repaired by replacing the tensioners or that being identified as the cause (no sound when starting and cold, occasional noise when warmed up and in idle).

    Bleh, not sure what to do about it. Pretty sure a dealer would say it wouldn't be a warranty job because the tensioner isn't broken (yet).

    Must buy aftermarket pipe to drown it out.

    Suggestions welcomed.