1978 XS650E Standard - Consistent Whining Engine Sound

authenticnovelty

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Hi Everyone,

In the last month or two my bike started making this whining noise. I've changed out a number of parts recently while restoring the bike, specifically the clutch plates/springs. I have tightened and loosened the timing chain and adjusted the ignition timing to match since this sound has appeared. Have also cleaned and greased the cam shaft between the points and timing advance unit. So far no adjustments have made an impact.

The noise begins when the engine starts and ends when the engine stops, in gear or in neutral, same intensity throughout. It changes pitch with the speed of the engine. It's a very smooth noise, almost like an electric motor. I feel like I've heard similar noises come from modern fuel injected cars, like perhaps an alternator whine? I honestly initially thought it may be related to the charging system. My existing wet battery had sulfated and was having trouble holding a charge at the time. I've since replaced the battery for a new AGM and have followed the multimeter diagnostics for the charging and ignition system from the Clymer/Yamaha Manual, replacing the brushes, regulator and rectifier shortly after the battery. I have not disassembled the rotor/stator or looked closely at that area yet, but the resistance for the rotor appears within spec.

The sound has not appeared to impact performance of the engine. Planning to pick up a mechanics stethoscope this week and listen around to see if I can narrow down to an area of the engine.

I've seen number of posts inquiring about odd engine sounds. Not much luck in finding similar with audio samples or solutions on the forums yet. I've attached a video of the whining noise my '78 is making below for reference.

Any suggestions are greatly appreciated. Thanks in advance!

 
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xjwmx

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Check the ends of the crank for wobbling, using just the starter

Other than that, another likely candidate is front cam chain guide. If tilting the bike affects the sound, it would be a good indication. Since you're going to open it up anyway, you could loosen the bolts for the cam chain guide and move the guide around using the bolt heads. If that affects it, it's the cam chain guide. Loosening the adjuster at the back might possibly affect it too.
 
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authenticnovelty

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Thanks for all the suggestions thus far. I checked around on the engine tonight with a stethoscope and seems most pronounced when listening to the engine casing just behind the silver oil delivery pipe, about where the cam chain guide would be. I did not notice the noise from near the cam chain tensioner with the stethoscope. Just seeing all the replies now. Will recheck the specific areas mentioned above. Would be a dream if as simple as the tach cable, willing to check. I did not notice abnormal noise when using the stethoscope near the oil pump/tach cable/side oil screen area today though. The sound was more pronounced near the stator cover than the clutch side. I don't believe I've noticed a change in sound when leaning the bike, but will look more closely again this week.

Regarding filters, I had a couple plastic chunks in my sump filter on the last oil change a few weeks after the noise had appeared in December. Small metal shavings and black plastic debris were also in the side oil screen (photo attached).

I have tested the bike recently both with a very loosely adjusted cam chain and with the tension set at initial cold idle, as suggested on this forum. The clanking of the cam chain becomes audible when loose, but this whirring noise remains unchanged regardless of adjustments, which leads me to believe it may not be the chain. I did notice today that it started out quiet and reached the full volume matching the video once warmed up. I assume the part in question is expanding with heat?

The link TwoManyXS1Bs suggests is promising, but video samples seem to only demonstrate the noise when in motion. Definitely a similar sound. Haven't had a chance to read through the full thread yet.
 

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5twins

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The rubber "shoe" on the aluminum front guide may have fallen right off. They do that sometimes. The front run of the chain is pretty much always under tension from the crank spinning and pulling down on it. Adjusting the tensioner loose or tight on the rear might not change the front run of the chain much, or the sound it's making. Check the drained oil to see if it's full of fine metal flakes. That usually means the rubber is gone on the front guide and the chain is running against aluminum .....

GSzF2dl.jpg
 

gggGary

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Any history on the bike? miles, how hard it's been run, lack of oil etc?
Yes, 2M, XJWMX: open alternator cover, watch the rotor for wobble. crank spreading...
 

MaxPete

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Hi AuthenticNovelty:

Interesting noise you’ve got there. IMO, it isn’t likely the speedo or speedo cable because they only turn when the front wheel turns. I do have couple of other thoughts:
  1. Simply disconnect the tach cable under the instrument (15 seconds with some pliers on the knurled connector nut) and see if the noise is gone. If so - you’ve got a bad instrument.
  2. Disconnect the other end of the tach cable (identical knurled nut down on the RH engine case) - if it goes quiet, you’ve got a bad tach cable.
  3. If you’re getting lots of plastic in the oil >>> suspect your front timing chain guide. I had a similar thing with my 1976 Standard XS650C (aka Lucille). I was riding when suddenly, I heard what sounded like a soft knocking sound in the front/top end of the engine. It turned out that the front guide had shed its plastic “shoe”. The sound was the suddenly-loose timing chain slapping against the bare metal guide.
I cannot explain why your noise is a whine rather than a knock, but maybe your chain is tighter than mine was.

My entire tail of woe is covered in a thread entitled “Lucille pulls another one on me”. I’m sorry, but I can’t recall how to pull up the actual link (on a lot of meds right now). The thread contains quite a lot of info on front timing chain guides including where to get them and comparisons of various sources of supply.

Best of luck!

Pete
 

authenticnovelty

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Unfortunately i don’t have much history on the bike before me. I have owned it about 7 months. Bought it with roughly 11,900 miles. Now has about 14,500 miles. Previous owner was a dealership technician in western Pennsylvania. He bought it for a personal cafe project when someone traded it in. He used it around the dealership and on short runs around town when working there. Then winterized and checked up on it for four years in his garage when the dealership closed. Claims to have never personally run ethanol in it. The carbs were super clean. cleaner when I bought it than the most recent time I opened them last month. He was moving and had to Sell. Seemed very knowledgable and responsible. Luckily he kept the bike almost entirely stock. A previous owner before him apparently installed an exhaust from an XS650 Special in the last 40 years, for whatever reason.

Gave the whole bike an initial once over and properly welded exhaust brackets on the frame the weekend it was purchased. Before this noise, the biggest issues I’ve had so far have been related to dried/cracked seals leaking oil (cam shaft, valve covers, shifter seal, etc) and air leaks on the BS38 carburetors that ive been slowly troubleshooting (what seems like a perpetual fight with leaking throttle shaft seals and good carb boots).

I did have some fine metallic sparkle in the oil change last month, but not so bad as in 5twins photo.

I changed the oil, replaced oil filters, replaced friction plates and clutch springs all in the process of accessing the electric starter bendix to tighen. I dont have access to a garage space (usually work on the street), so i figured i would cover all my bases at a friend’s place in one afternoon while the case was open. the clutch seemed to be slipping between 4th and 5th gear and who knew what condition was inside.

Conveniently, i have a photo of the famed #4 gear from that day and there is deterioration of plastic on it (image attached). Could very well be what was in side screen. The starter is not staying engaged though. Occasionally it lags to disengage for a half second when starting, but it always turns off.

The two chunks of plastic in my sump filter were straight though. Maybe 3/8” long 1/16” wide. I unfortunately didn’t keep them as evidence (you always regret the parts you toss).

I can send a video of the stator spinning with the cover off, if that is the shaft you are asking about wobble. Any spinning parts I’ve observed have seemed solid so far.
 

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MaxPete

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The plastic off the FRONT timing chain guide seems to appear as long (1” or even more) strips approx. the cross-section of a toothpick. The starter gear debris comes out in the oil strainers as smaller granules - around thie size of coffe grounds.

The debris from the two failure modes are quite different, at least in my limited experience.

BTW - from what I can tell, the REAR timing chain guide seems to live virtually forever. I couldn’t find any history of significant problems with them. If, however, you do have a rear guide problem, I have a used spare in good shape that is yours for the shipping (and I can ship from the US via USPS).

Lemme know.

As for a bent crank being a cause - I’d say that is quite unlikely. The XS650 crank is generally regarded as extremely robust.

Pete
 
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member3480

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If you need a motor I have a couple here that run and maybe willing to sell one. Other wise I would pull the top end because it does sound like a cam chain guide that rubber broke off. Very common on these older bikes.
 

TwoManyXS1Bs

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... I changed the oil, replaced oil filters, replaced friction plates and clutch springs all in the process of accessing the electric starter bendix to tighen...

. The starter is not staying engaged though. Occasionally it lags to disengage for a half second when starting, but it always turns off...

Perhaps a clue there.
If the starter bendix fails to fully withdraw, the crank's gearteeth could grind on it...
 

authenticnovelty

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Thanks MaxPete and DaddyGCycles for the parts offers! Will keep in mind as I continue troubleshooting this. I do not think I will have a chance to properly investigate the bike again for a few days. However, I ran some errands on it briefly this morning and paid particular attention to the front of the engine when starting cold and warming up. While the noise is a very consistent soft smooth whirring like an additional electric motor, it actually sounded more like subtle chain links when initially cold, before the noise reached full volume today. I had not noticed that previously. Also, the larger chunks at the sump were very similar to described. One of them may have been as long as 1/2" to 3/4", but definitely toothpick-like.

Not ruling it out yet, but I don't think it's related to the electric starter at the moment. I can distinctly hear when it disengages and didn't notice any significance to the areas of the case where the number 4 gear or the starter would be with stethoscope.
 

5twins

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The front guide has narrow lips of rubber running down both outside edges. These are what start breaking off first and are what are responsible for the long, toothpick-like pieces you've found in the sump filter. Finding them doesn't necessarily mean the guide is totally shot yet but indicates it's condition has started to degrade.

h5dQttM.jpg
 

authenticnovelty

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Finally got a moment to take a look at the engine with the stethoscope again today. While the sound appears to be on the top end while hovering around with ears, through the stethoscope it is definitely most significant from the lower front of the case. Specifically on the left side near the stator (have included images of loudest areas if useful). I'm willing to believe it is the cam chain/guide/tensioner (or that they at least should be addressed in the near future), but how likely could it be something relating to the rotor/stator? I also have had an oil leak from my left side case cover that I cannot trace. I've looked at the pushrod seal multiple times and I've taken the guard off the shifter rod and looked in the general area of the shifter seal and they seem only to have possible oil/grease related to the drive chain. Meanwhile, the length of my bottom frame and entire side stand have thick oil caked on them, even as soon as a couple weeks of regular riding after washing. Could they be related?

I initially passed over this thread below thinking it was not a similar sound. The more re-read it and I listened, I think it may be the same symptoms and issue as mine. The audio quality very poor/highly compressed in the sample, which distorts it into more of a roar, but the patterns are the same. His solution was never revealed, but it definitely was not cam chain, starter or clutch related.

http://www.xs650.com/threads/help-with-crazy-ass-noise-video-included.24950/

Is anyone aware of how this thread was resolved?

Thanks again for the suggestions thus far.
 

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authenticnovelty

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I can send a video of the stator spinning with the cover off, if that is the shaft you are asking about wobble. Any spinning parts I’ve observed have seemed solid so far.

No wobble. I'm assuming crank spreading would need to be evaluated with the engine out of the frame and apart? I was referring more to the idea of something unexpected behind the stator cover or rotor being an issue or additional symptoms to look for once removed.
 

xjwmx

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The oil prob, on the left, do you have oil inside the generator area? If it's the crank seal it can be replaced from outside, trick is a 1 1/2" sink repair plastic pipe to tap it in with. And one of those $5 eagle beak pullers to get the old one out.
 
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