Post by: SteveR on October 11, 2016, 10:06:02 AM
. The ST, however, had no dramas at all... except...On warming up I heard a sound I hadn't noticed before... it's a little concerning as it sounds 'metallic' and 'grating' to me. I'll try to attach a video clip: https://vimeo.com/186346460 (https://vimeo.com/186346460) it appears just after pulling the throttle, on quick revs you can hear it 'wind up' just as the revs are going down, on longer revs it starts up and keeps time with the engine. It 'appears' to be coming from the left side of the engine... I'd really appreciate any insight!
Post by: winston66 on October 11, 2016, 12:22:49 PM
Cheers ,
Winston66
Post by: Yorkie on October 11, 2016, 08:41:08 PM
Post by: SteveR on October 11, 2016, 09:01:31 PM
Post by: Biggles on October 11, 2016, 09:08:43 PM
I thought it was normal, but waited until a couple of real experts confirmed it. :grin
Post by: Greencan on October 14, 2016, 07:37:32 PM
Is it that metallic clicking you refer, the noise immediately after you tweeked the throtle as the engine returns to idle?
Post by: SteveR on October 14, 2016, 09:29:56 PM
Hi Steve...
Is it that metallic clicking you refer, the noise immediately after you tweeked the throtle as the engine returns to idle?
Yes, that's the one. It's also present when holding the throttle open for longer too, it's probably just obscured by the normal engine noise in the video though.
Post by: Greencan on October 14, 2016, 10:29:40 PM
OK...what you say makes sense, as the torque of the engine either on acceleration or deceleration the sourse of that noise it loaded. So movement that contributes to noise is muted.
You need to think of a component (like the steel disc that's affixed to the left bank timing belt pulley). I havent a clue where precisely that noise is coming from, just by listening to the vid. But I make mention of the timing belt guide simply as a thought, you can imagine if that 8mm guide bolt were to come loose, then that belt guide disc would rattle against the alloy gear, except when the engine was under load (the belt would mute it).
Other possibilities are, loose exhaust heat shield, stone or a detached nut caught in the header heat shield, something broken off in the exhaust header pipe collector (tho these last suggestion are more likely to produce rattles when the engine is loaded), damaged alternator drive coupling, or any component thats driven, that if it either damaged or loose, might cause noise when not under load.
Dunno if your going to Hepburn tomorrow, but I will put a stethescope with a probe in my pannier tomorrow. I am meeting a Mate in Gisborne for a coffee at 10, so if the weather gods are kind, will pop over to the pub at lunchtime.
Sorry but best I can offer on an iphone.
Cheers.
Post by: SteveR on October 15, 2016, 08:30:36 AM
Post by: hobs on October 15, 2016, 10:01:16 AM
May be way off, but testing under different conditions may help.
Cheers,
Hobs
Post by: Greencan on October 15, 2016, 03:47:31 PM
Twas good to catch and sort that pesky metallic rattle out... if and when you want I'd be happy to repair that shroud, or take up Onsie's offer and get a replacement from him...in the meantime if you were to place a washer either side of shroud that are marginally larger than bolt flange and are thin enough, that too would in all likelihood solve the problem.
Too easy :-)
Cheers, Dick :-)
Post by: Brock on October 15, 2016, 03:55:44 PM
Post by: Jdbiker on October 15, 2016, 08:58:29 PM
Hiya Steve...
Twas good to catch and sort that pesky metallic rattle out... if and when you want I'd be happy to repair that shroud, or take up Onsie's offer and get a replacement from him...in the meantime if you were to place a washer either side of shroud that are marginally larger than bolt flange and are thin enough, that too would in all likelihood solve
Cheers, Dick :-)
Well done Dr. Greencan on diagnosing SteveR's rattle :like :like
Post by: Greencan on October 17, 2016, 01:51:13 PM
Funny how sometimes run in pairs or 3's...well have found another heat shield I thought was either cracked or broken generating an aweful rattle around 2200RPM...turned out to be no more than 2 of the 3 retaining fasteners were approx a turn loose and the 3rd just needed a spanner to it.
So Steve, as that section I suggested may be damaged...may not...it might just need U to check the fasteners for tightness, no more than that and the 3 fasteners (2 top and 1 facing fwd at the front) can be accessed without any fairing removal...yes it is a little arkward, but after replacing all the coolant hoses beneath the inlet manifold without removing the carburetors...this check will be a doddle ;-)
Post by: SteveR on October 21, 2016, 09:09:54 AM
It also makes sense why I hadn't noticed it when I left home that morning (or any other time before I posted the question here); When the bike is cold, it's ok, as it warms, the thin metal of the shields would expand just enough to let that crack vibrate. By that time I've usually got my helmet on and am down the road, but when I shot that video, I had the bike running for a while trying to jump-start another bike. Last Saturday I 'thought' I heard it after filling up, probably just far enough down the road for the engine to have warmed slightly... Anyway, whatever the reason, at least now I know what to do about it, Thanks again!!