Topic: Is this popping sound when rotating the chain normal??

[Dave-and-his-550]

I decided to make a video of this strange sound to make things simpler. Can anybody give me a clue as to what this might be? Has brand new chain and sprockets. I can't really tell where it's coming from. '76 550F. Any ideas?

[MCRider]

If indeed its new chain and sprockets, then I vote its too tight.

While its barely OK on the centerstand, drop it down and sit on it or have someone sit on it and check the tightness. I'll bet its like a bow string.

Do it and if I'm right I'll tell you why. If not never mind.

[Fritz]

Had the same problem. Also a '76 550F but with a little more slack in the chain.
My first thought was the bearing on the drive shaft. Then I suspected the front sprocket that has a little bit of side movement on the shaft.
I took it off and put some grease on the splines and the sprocket retainer. Then decided to add more slack to the chain -> silence

[Dave-and-his-550]

Thanks for the quick help guys. I have not tried adjusting it with someone on it. Silly me, because it states to do that in the manuals doesn't it? Fritz, I also have a little bit of jiggle and side movement from the front sprocket, I kind of thought that was what was making the noise.

[IndyFour]

I think its definitely coming from the front sprocket area.  As I watch the video, the pop seems to happen at every full revolution of the front sprocket.  Is the sound coming from inside the case?  I'm sure it's hard to tell.

Did you try spinning the front sprocket with the chain off to see if it did it without the chain putting pressure on it?

[MCRider]

Thanks for the quick help guys. I have not tried adjusting it with someone on it. Silly me, because it states to do that in the manuals doesn't it? Fritz, I also have a little bit of jiggle and side movement from the front sprocket, I kind of thought that was what was making the noise.

No the manuals usually say to do it on the centerstand. But if you look at the geometry of the swingarm, obvious in your video, as the wheel moves up through its arc, it gets further away from the contershaft sprocket and will get REAL tight. My position is the chain should be adjusted to its proper slack at the point where the wheel is furthest from the swingarm. YOu can only do this by getting some weight on it. Then once its done, you can put it on the centerstand and gauge how much slack it has, it will be more than suspected. But that's where you'll adjust it to when you're by yourself and its on the centerstand, knowing it will be al right with some weight on it.

Back to your problem, there is the chance of a bad countrshaft bearing but thats very rare. I still vote the chain is too tight.

And the sprocket will be a little sloppy on the shaft, thats a self centering allowance.

[Dave-and-his-550]

IndyFour, you are right. It DOES pop on every full revo of the front sprocket.

I loosened the rear tire. The chain is very slack and I rotated it, and it still pops at the same point, but now its not as loud.

My first thought was the bearing on the drive shaft.

Soo Fritz, MC, should we assume this avenue? I'm guessing you both are referring to the same issue about the bearings.

I'll go ahead and try adding more grease to the splines and retainer. But if it still pops...Should I check the bearings on the drive shaft next...?

UPDATE: I removed the chain from the front sprocket as well as the sprocket itself and spun the driveshaft around freely. It did not make a popping sound at all. So it must be from the weight of the chain and rear tire.

[MCRider]

IndyFour, you are right. It DOES pop on every full revo of the front sprocket.

I loosened the rear tire. The chain is very slack and I rotated it, and it still pops at the same point, but now its not as loud.

My first thought was the bearing on the drive shaft.

Soo Fritz, MC, should we assume this avenue? I'm guessing you both are referring to the same issue about the bearings.

I'll go ahead and try adding more grease to the splines and retainer. But if it still pops...Should I check the bearings on the drive shaft next...?

UPDATE: I removed the chain from the front sprocket as well as the sprocket itself and spun the driveshaft around freely. It did not make a popping sound at all. So it must be from the weight of the chain and rear tire.

A bearing would be unfortunate. What's the history on this dude? Prior abuse?

I think I would reinstall everything, with the looser adjustment,  and ride it a bit. Then check for the pop. 10 to 20 miles. But a bearing could be bad news, but should make itself known before catastrophic failure. Never known of one to fail on anything less than a dragracer.

[northwestdrew]

just a question are your motor mounts tight it appears in the vid that every time it pops the engine moves or is this normal 

[domer]

does it make the same sound with the old chain?

[dave500]

check its in neutral properly,it might just be not quite selected fully,try rocking the bike back and forth and put it in 1st or 2nd,then whilst rocking it select neutral again and make sure its settled correctly.audio is like paint shades on the computer,not the same.

[Dave-and-his-550]

Well as I said I removed the front sprocket and I spun the driveshaft around and no popping. I think I'll go with MC's suggestion and ride it around for awhile.

Drew: I never did remove the engine when I did the top end rebuild, so everything should be torqued well and tight.

Domer: I cannot remember if it made that sound with the old chain 

If it was a driveshaft bearing failure, wouldn't it be popping when I spin the driveshaft itself? Which it doesn't...So I think I'll be good.

Dave500: Definitely in neutral mate.

[dave500]

ok dave cool,ive seen guys with motors off trying to select gears with out rocking and it just frustrates me,i feel like yelling at them,rock the thing back and forth will ya!your on the ball though.

[seaweb11]

It sounded to me like the suction of oil as the chain comes out of the bottom of the sprocket.
What I mean is .....there seems to be a lot of oil goo on the chain. Could be it?

What do I know?

[haill]

did you check that the front sprocket was for a 550.
the PO on mine, had placed a cb750 sprocket on mine causing this condition.
there's a flanged machined into the front sprocket which shims it out further, placing the chain in line with the back sprocket.
if you have purchased a front sprocket for a 750 by mistake, it doesn't have this flanged and the chain will be out of line.
also just watched your video and believe your sprocket is around the wrong way. the flange should be to the inside.

[Kevin400F]

Are the bolts holding the retainer clip to the front sprocket longer than stock, and fouling against the case behind the sprocket? 

[CBJoe]

Are the bolts holding the retainer clip to the front sprocket longer than stock, and fouling against the case behind the sprocket? 

I like that one....

[Cqyqte]

Well as I said I removed the front sprocket and I spun the driveshaft around and no popping. I think I'll go with MC's suggestion and ride it around for awhile.

Drew: I never did remove the engine when I did the top end rebuild, so everything should be torqued well and tight.

Domer: I cannot remember if it made that sound with the old chain 

If it was a driveshaft bearing failure, wouldn't it be popping when I spin the driveshaft itself? Which it doesn't...So I think I'll be good.

Dave500: Definitely in neutral mate.

Do you have a dial mic?  If so, I'd remove the chain after marking the front sprocket so you know the position of it when it makes the noise.  then I would rotate the front sprocket with the dial mic shoe running on the shaft to see if the shaft varies in position just as it passes the marked position.  If there is an eroded ball in the bearing the shaft may deflect at that point.  The pulling force of the chain will amplify the deflection.  So as you rotate the sprocket check the front to back deflection with the dial mic.

[domer]

if you have the old chain, id give it a whirl... possible you could have a bad link in the new one. especially if you didnt notice it before the new chain.

[Dave-and-his-550]

Sprocket is correct for 550, and how I had it installed was correct according to the parts page pictured below.



Is the bearing you guys are mentioning #34?

I was wrong with what I said before...I grasped the driveshaft and spun it around while pushing on it with force, and I did notice a very faint popping sound so I guess a bearing might be bad after all...

I can still ride it like this, without much issue right? I mean, its not like the piece holding all the bearings in will break up and all the steel balls will fly out everywhere in my transmission and #$%* it all up, right?! That would be a horrible scenario...

[Cqyqte]

Worse case is that your bike sat for many years and acid in the oils etched the race and a ball.  Under load the flat weakened spot on the ball is causing the click.  That ball could fracture and fail causing shardes could fly into the tranny and take out many other pieces.

I would get it replaced now before you end up crying over the loss of the tranny.

[Dave-and-his-550]

Well the bike does have 26,000 miles on it...

[Cqyqte]

Where in the 26000 did it sit near the end?  Because if you resurected it 500 miles ago you're not wise to run it that way.

[Dave-and-his-550]

It has been sitting for about a year, as I was working on it. I've owned it for about 5 now. Never noticed the noise before when I was riding it before last year. I haven't ran it yet after the rebuild, but I really wanted to.

Cqyqte, could you give me the gist of replacing that bearing? How long it would normally take, and what needs to be pulled out?

[lone*X]

I may have missed this in the thread but is the new chain an Oring chain?  Also, is the master link clip on the outside of the chain vs the inside?  Could be a clearance issue.