Rattling noise from rear cylinder at idle
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Squid
Joined: Aug 2012
Posts: 26
Rattling noise from rear cylinder at idle
Morning all,
I had my bike out last night for a run to town for dinner. It's been garaged mostly the last couple of months because it's cold and I'm soft. When I do get it out it starts fine, warms up reasonably quickly and runs well (this is all past tense...). On the way home last night I pulled up at the lights and heard a rattling sort of noise that seemed to be coming from the rear cylinder. Only at idle, and maybe very low revs (<1800rpm). Still makes the noise if I clutch in at speed. No noise when accelerating, cruising or engine braking. I ride with plugs in and anything I can hear over the exhaust is significant, so it's not subtle.
For the record, Kreiger mCCTs went in when I got the bike at 70,000km (now at 90,000) and I'm running old style 2bros exhausts. Recently did an oil and filter change with Motul 5100 10W/40.
Power does not seem affected at the low end - I didn't rev high on the way home with the noise because I didn't want to blow anything up, took it easy. Next weekend I will try pulling the valve cover and see what I can see. In thw meantime, any lightbulbs? CCT was my first thought but (a) they can't really fail, it hasn't moved from position and (b) no power loss or grenading.
Thanks team
I had my bike out last night for a run to town for dinner. It's been garaged mostly the last couple of months because it's cold and I'm soft. When I do get it out it starts fine, warms up reasonably quickly and runs well (this is all past tense...). On the way home last night I pulled up at the lights and heard a rattling sort of noise that seemed to be coming from the rear cylinder. Only at idle, and maybe very low revs (<1800rpm). Still makes the noise if I clutch in at speed. No noise when accelerating, cruising or engine braking. I ride with plugs in and anything I can hear over the exhaust is significant, so it's not subtle.
For the record, Kreiger mCCTs went in when I got the bike at 70,000km (now at 90,000) and I'm running old style 2bros exhausts. Recently did an oil and filter change with Motul 5100 10W/40.
Power does not seem affected at the low end - I didn't rev high on the way home with the noise because I didn't want to blow anything up, took it easy. Next weekend I will try pulling the valve cover and see what I can see. In thw meantime, any lightbulbs? CCT was my first thought but (a) they can't really fail, it hasn't moved from position and (b) no power loss or grenading.
Thanks team
Retired- but not tired!
SuperBike
Joined: Aug 2010
Posts: 1,481
From: Pittsburgh
I agree it's worth pulling the valve cover and inspecting for proper chain tension - the MCCT can't fail but the tensioner assembly it pushes against may have changed or deteriorated. But hopefully nothing more than some loose exhaust parts. Hope all's well once determined.
Thread Starter
Junior Member
Squid
Joined: Aug 2012
Posts: 26
Doesn't sound like exhaust, but I admit I cannot entirely rule it out. Sounded to me like something loose, but I hear that exhaust catches people that way
could be, but this came on quite suddenly, no build-up
it was still in place when I checked it at the servo, but can't rule it out so I'll re-tension front and rear to spec
Hopefully something simple like that, or exhaust. Seemed too loud to be an exhaust leak but saying that I've never had one
could be, but this came on quite suddenly, no build-up
it was still in place when I checked it at the servo, but can't rule it out so I'll re-tension front and rear to spec
I agree it's worth pulling the valve cover and inspecting for proper chain tension - the MCCT can't fail but the tensioner assembly it pushes against may have changed or deteriorated. But hopefully nothing more than some loose exhaust parts. Hope all's well once determined.
Thread Starter
Junior Member
Squid
Joined: Aug 2012
Posts: 26
Senior Member
SuperBike
Joined: Sep 2010
Posts: 1,994
From: Bisbee, AZ
You have MCCT with 20k on them. As Jerry suggested maybe it time for an adjustment. What doesn't fit is the sudden onset of the sound. If it were me I would dump the oil in a very clean pan (that way you can reuse if nothing shows up). Drain it through a screened funnel and look for pieces of the tensioner. CAM CHAIN TENSIONER #3
Maybe the MCCT was set too tight and the tensioner has partially failed . I know it's unlikely but I wouldn't run the bike until I solved the issue. Did the sound start on the first ride after the oil change?
Maybe the MCCT was set too tight and the tensioner has partially failed . I know it's unlikely but I wouldn't run the bike until I solved the issue. Did the sound start on the first ride after the oil change?
Last edited by xeris; Aug 11, 2014 at 05:36 PM. Reason: add text
Thread Starter
Junior Member
Squid
Joined: Aug 2012
Posts: 26
You have MCCT with 20k on them. As Jerry suggested maybe it time for an adjustment. What doesn't fit is the sudden onset of the sound. If it were me I would dump the oil in a very clean pan (that way you can reuse if nothing shows up). Drain it through a screened funnel and look for pieces of the tensioner. CAM CHAIN TENSIONER #3
Maybe the MCCT was set too tight and the tensioner has partially failed . I know it's unlikely but I wouldn't run the bike until I solved the issue. Did the sound start on the first ride after the oil change?
Maybe the MCCT was set too tight and the tensioner has partially failed . I know it's unlikely but I wouldn't run the bike until I solved the issue. Did the sound start on the first ride after the oil change?
Noise started about 400km (?) after recent oil change, third or fourth ride.
Thanks jerryh. I usually do the filter every second change (so about 10,000km/6,000mi), so it's done 5,400 odd km without issue, but a $10 filter is good insurance, specially if its gonna be full of bits of tensioner
Thread Starter
Junior Member
Squid
Joined: Aug 2012
Posts: 26
Ok I pulled the rear cam cover tonight to see what I could see. Everything looked fine, tensioner blade seems intact, tension adjuster not significantly moved. I re-tensioned front and rear mCCTs. Exhaust manifold (rear) also seems very snug, no movement. Can't rule out slight leak I guess, but I'm iffy about that, didn't sound anything like exhaust. So nothing to show for a few hours work. I'll fire it up on the weekend, I don't live in the sort of neighbourhood where cranking the two-brothers at 9.30 goes down well on a weeknight. I will record a video, too, and see if I can pinpoint the nosie
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