whine from engine

Hey every body, my Seca has intermittently been emitting a whine from the engine. The whine's pitch will increase with engine speed and is present when the machine is stopped or in neutral. It starts after High rpms and will stop at low rpms, though not right away.

Example: Im commuting on the highway, as I come to a stop the whine will become present as ambient noise dies off. After coming to a stop, with the machine idling, the whine is still present but will suddenly stop.

The whine may or may not return as i finish my commute.

In my Haynes manual under fault diagnosis the closest thing I can find, (that I believe is the source) is under TRANSMISSION NOISE: "worn or damaged bevel gear sets. a whine emitted from either bevel gear set is indicative of improper meshing"

Can any one explain this last phrase?

any ideas/advice will be greatly appreciated

p.s. the odometer just rolled over 30K

 

Alternator. At least that's my first guess based on the miles on the bike. While there are of course other possibilities, I'd start there. Check the battery, too. The alternator will "cry out" if it's having problems charging the battery.

Unless it has nothing to do with the motor and your mechanical tach (or cable) is having issues. Tachs have been known to howl loudly when in need of attention.

If it were the transmission/gearbox/drive train it would change between moving and not moving.

 

my xj700 speedo cable will scream when it's cold. ANY ride under 55 degrees, will guarantee a screaming cable if I go over 53 mph. It will do that untill I get down under 25 mph, and sometimes even as low as 15 mph, before it will stop. When the noise does stop, the speedo needle gives a small twitch as the sound stops. Just before it stops, the needle bounces a little bit then the twitch. Once it stops, I can speed back up but gotta stay below 53. If I'm in traffic, I'll just stay at 55-60mph, let it make it's noise until I can safely slow down or get to a traffic light or sign.

Once the temp gets to around 60 degrees it doesn't do it at all.

Dave F

 

Yeah, I second trying the tach/speedo cable. Disconnect and see what happens on your next ride. From what you're saying it would be the TACH since it happens at a stop.

Is it regardless of clutch action? Thinking throw out bearing, too.

How would you test the alternator? Unplug it, maybe?

 

The "throwout bearing" isn't enough of a bearing to really whine being just a wafer and all. Not impossible but highly unlikely.

You absolutely DO NOT unplug the alternator. You test the alternator by putting a meter on the battery terminals and running the motor up to 2500rpm and seeing if the voltage rises to 14.5 and holds there.

 

I say tacho, you wouldn't believe what a hideous noise could it can cause, one shot of lube up into the tach where the cable is should fix it.

 

Okay first off you guys are awesome,

Alternator is charging with 14.5 volts (replaced the battery with a sealed gel a few months ago). I removed the tachometer cable and the lower end was covered in black sludge, & the top end was as dry as a bone. I cleaned the cable and the sleeve with GUNK, these are drying now.

I believe the cap for the tach to the cylinder head came loose allowing the lube to drain out. Hopefully this will remedy the "whine", I will update after I ride home.

 

Yep that was it. I lubed the tach and she purred all the way home.

 

I didn't think these bikes were new enough to be equipped with a cat? :? :lol:

 

A quick note in regard to the accumulated black goo around the lower end of the tach cable: it's likely you need new tach drive oil seals. It's not covered in any of the manuals, see: http://xjbikes.com/Forums/viewtopic/t=19538.html