sdhow Posted December 1, 2015 Share Posted December 1, 2015 Getting a pronounced "rattle" under acceleration that appears to be coming from the front of the motor; come off the throttle and it goes away. Is there a replaceable bearing in the alternator rotor that could cause this? Link to comment Share on other sites More sharing options...
czakky Posted December 1, 2015 Share Posted December 1, 2015 No bearing there. Are you sure you aren't pinging? If it is under heavy load (4-6th gear) and under 5k RPM more pronounced in the heat my bet is pinging. Sounds like a can of spray paint being shaken. Link to comment Share on other sites More sharing options...
Scud Posted December 1, 2015 Share Posted December 1, 2015 If it is under heavy load (4-6th gear) and under 5k RPM more pronounced in the heat my bet is pinging. Sounds like a can of spray paint being shaken. Agreed. I get that sometimes, and downshifting makes the rattling sound go away. It is replaced by a 6,000 RPM growling sound without the shaking paint can accompaniment. These motors do seem happiest in the mid to high RPM range. Link to comment Share on other sites More sharing options...
sdhow Posted December 1, 2015 Author Share Posted December 1, 2015 Nope, I know pinging when I hear it. It's more of a "jutter"ing sound, like vibration induced. So the rotor is just direct-mounted on to the front of the crankshaft? There's got to be some kind of bushing material or something, no? Also, do they balance the entire alternator (rotor/stator) assembly at the factory? Link to comment Share on other sites More sharing options...
docc Posted December 1, 2015 Share Posted December 1, 2015 Timing chain tensioner? Maybe a loose exhaust junction, or loose baffle inside the stock crossover (behind the gearbox)? Link to comment Share on other sites More sharing options...
GuzziMoto Posted December 1, 2015 Share Posted December 1, 2015 Yes, the alternator rotor is mounted directly to the end of the crank. Not much there to rattle. The rotor is balanced. Later bikes have a front crossover between the head pipes, and that is a common source of rattling. Or it could be a loose head pipe at the head. If it only does it under acceleration it would not be a balance issue, balance it not only important under acceleration. It could be a loose exhaust, but it really sounds like ping / knock. What rpm are we talking? Link to comment Share on other sites More sharing options...
gstallons Posted December 1, 2015 Share Posted December 1, 2015 Sometimes the rotor can come loose and make a knocking sound . This is a very small chance though . Link to comment Share on other sites More sharing options...
sdhow Posted December 1, 2015 Author Share Posted December 1, 2015 What's the torque call out on the bolt? I may pull the cover this weekend and inspect it just to set my mind at ease. The more I listen to it, the more it may just be top end (valvetrain) noise. I'm used to my 1200 Sport; this may just be louder and "tinny"-er due to the valve cover design. Link to comment Share on other sites More sharing options...
docc Posted December 1, 2015 Share Posted December 1, 2015 Checked your valve adjustment? Link to comment Share on other sites More sharing options...
sdhow Posted December 2, 2015 Author Share Posted December 2, 2015 Valves were adjusted at 6,000 miles. Not quite at 8,000 now. I was told these things have an inherently noisy top end. Is that incorrect? Would it only rattle on acceleration? I just got this thing balanced with the TBs and all, so I didn't really notice the noise before...because it coughed and sputtered so bad! Link to comment Share on other sites More sharing options...
czakky Posted December 2, 2015 Share Posted December 2, 2015 With stock exhaust I could hear my valves up to around 70mph with my helmet on. You would hear the valve clatter at idle and all the way up though. In my experience. What RPM are you hearing the rattle? If you're confident it's not pinging the front cross over and exhaust in general is where I would look. Link to comment Share on other sites More sharing options...
docc Posted December 2, 2015 Share Posted December 2, 2015 Sure the valve train is "noisy", but probably more noticable at idle. No front cross-over on an '02, but the exhaust is a good place to start. My lower "box" cross-over had a loose baffle that rattled. Also, the steering damper mount can loosen from the lower triple tree. Check also the sidestand fasteners and mounting bolts for the front sub-frame to engine, oil cooler brackets, and (again) the header pipe flanges. Link to comment Share on other sites More sharing options...
grossohc Posted December 2, 2015 Share Posted December 2, 2015 I used to get a rattle from the front of the bike, really annoying. traced it to the bikini fairing hitting the headlamp, small piece of rubber and it was cured, Link to comment Share on other sites More sharing options...
Stick Posted December 2, 2015 Share Posted December 2, 2015 What's the torque call out on the bolt? I may pull the cover this weekend and inspect it just to set my mind at ease. The more I listen to it, the more it may just be top end (valvetrain) noise. I'm used to my 1200 Sport; this may just be louder and "tinny"-er due to the valve cover design. Would be nice if you told us the bike your dealing with. I assume, from the above statement, and your "list"... 02 V11 Le Mans, '08 1200 4V Sport, ...that it's the '08 1200 4V Sport? Link to comment Share on other sites More sharing options...
docc Posted December 3, 2015 Share Posted December 3, 2015 What's the torque call out on the bolt? I may pull the cover this weekend and inspect it just to set my mind at ease. The more I listen to it, the more it may just be top end (valvetrain) noise. I'm used to my 1200 Sport; this may just be louder and "tinny"-er due to the valve cover design. Would be nice if you told us the bike your dealing with. I assume, from the above statement, and your "list"... 02 V11 Le Mans, '08 1200 4V Sport, ...that it's the '08 1200 4V Sport? Uh-oh . . . I was assuming the 2002 V11 LeMans? Link to comment Share on other sites More sharing options...
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