Noise when transmission is engaged.

[BigOates]

I sorted out the electrical problem from the other day and am now noticing a noise coming what seems to be the left side of the engine. It's only there when the bike is in gear. It is absent when in neutral or the clutch is pulled in.

It's a 1980 special bottom end and ignition with 1981 special cylinders, pistons, and remaining top end. It almost sounds like something is vibrating loose?

I am running 15w-40 Rotella in the engine. Middle gear and final drive fluid levels all checked good. Just wondering if anyone has experienced this noise before, and any ideas of where to start looking?

Video of the noise. You can hear it real good around 22 seconds in. I'm alternating pulling the clutch in all the way and letting it out just enough to get the noise noticeable. Either way, I'm pretty sure it's not a normal sound...

http://youtu.be/ZMHxVXp3vKk

[WMarshy]

Did you recently do the work on the upper end? Did the noise manifest after recent work? Doesn't sound good IMO. Do you have the center stand? I wonder what would happen if you put it on the center stand and let the clutch out with it in first gear...let the rear wheel turn with no load at idle, then maybe add some load with the rear break to see if anything changes...

[DGXSER]

So with the bike in Neutral, the noise changes like that with the clutch pulled or released. The crank turns the Hyvo chain that turns the primary shaft where the starter clutch lives. On the end of the primary shaft sits the gear that drives the clutch outer basket. Upper right corner of this picture.



You also see in the lower right the oil pump idler gear, connected to the oil pump gear. It also turns whenever the engine is running. With the clutch disengaged, it is like the clutch is not installed as seen in the picture. None of the tranny shafts turn.

With the clutch engaged in neutral, only the main shaft seen sticking out in the pic above is turning. The countershaft, behind the bolt in the lower left is not turning. So it does not turn the middle drive or the rest of the drive train.

So your noise is being created by the rotation of the main shaft. I think you need to open the shift fork cover and pull the tranny pan. That sounds like something solid hitting the cases. Possibly something to do with the 2-3 shift fork, not likely though.

[trbig]

"You also see in the lower right the oil pump idler gear, connected to the oil pump gear. It also turns whenever the engine is running. With the clutch disengaged, it is like the clutch is not installed as seen in the picture."

Well, this part is not really correct. The basket is always turning and the basket is what drives the oil pump idler gear which drives the oil pump. Disengaging the clutch, meaning, letting the clutch handle out, puts power to that main shaft.

Anyway... in that pic that's posted, you can see the washer headed bolt that is left of the oil pump idler gear and under the main shaft. That has been known to back out and get ground on by the clutch basket gear. Mine only did the noise while in gear and it was really hard to tell which side it was coming from. So.. if you take off the left shifter cover and find nothing, you might take the clutch cover off and take a gander at that bolt.

[BigOates]

It makes that noise when releasing the clutch lever. The only work I did when I swapped the bottom ends was a new cam chain. Also a very light hone job on one of the cylinders because I replaced the a set of rings on cylinder 4 after I snapped them pulling the jugs off initially.

The dots line up on the cams. Also when I took it for a test ride when I noticed the noise, the bike shifts fine and there's no slipping out of gear.

I wouldn't know if the noise was there before, as I bought the bike and the parts bike in non running condition.

[BigOates]

I put it up on the lift (don't have a center-stand) and ran it through the gears with the wheels spinning. The noise was still there, but had decreased in volume somewhat. I pulled the engine side covers and removed the clutch (to double check the flange bolt that's known to back out) to check everything and it looks good. I guess I need to pull the oil pan and take a look up there and see?





Also the transmission is in 4th gear.

[DGXSER]

Well, this part is not really correct. The basket is always turning and the basket is what drives the oil pump idler gear which drives the oil pump. Disengaging the clutch, meaning, letting the clutch handle out, puts power to that main shaft.

Well, yes, that is true. My intention was strictly as it would apply to turning the tranny shafts. But your point is correct. As to disengaging or engaging, well, semantics in terminology. Disengaging can also mean pulling the clutch lever in, so it no longer turns the main shaft, or disengages the engine from the transmission.

As to your pics BigOates, I agree it all seems to be in good order. It is odd that you have the kick start gear in an 81 engine. Perhaps that engine is not the original to the bike. None the less, next step would appear to be pulling the transmission pan to see what can be seen.

[IanDMacDonald]

It's an 1980 bottom end

[trbig]

Well, yes, that is true. My intention was strictly as it would apply to turning the tranny shafts. But your point is correct. As to disengaging or engaging, well, semantics in terminology. Disengaging can also mean pulling the clutch lever in, so it no longer turns the main shaft, or disengages the engine from the transmission.

As to your pics BigOates, I agree it all seems to be in good order. It is odd that you have the kick start gear in an 81 engine. Perhaps that engine is not the original to the bike. None the less, next step would appear to be pulling the transmission pan to see what can be seen.

I didn't mean any disrespect.. was just pointing out to those that didn't know, but you made it sound like the motor runs the oil pump, and I was only clarifying the clutch disengagement for the same people.

[DGXSER]

I didn't mean any disrespect.. was just pointing out to those that didn't know, but you made it sound like the motor runs the oil pump, and I was only clarifying the clutch disengagement for the same people.

Its all good Todd. No disrespect taken. . Your clarification was spot on.

[BigOates]

Hey guys, just an update. I pulled the oil pan and noticed some rubber-like shavings and some fine metallic shavings. Decided to pull the heads and cylinders. The rear cam chain damper was bent and had been what look "shaved down." There was no middle ridge to speak of on it. I swapped it with a spare I had and am now awaiting a base gasket to arrive in the mail to reassemble. Hopefully the camp chain moving all over the place was the problem? I didn't see any other problems when I looked up through the oil pan. Anything else to check while I got her taken apart like this?

[natemoen]

am now awaiting a base gasket to arrive in the mail to reassemble.

Go to your local auto parts store and get some anaerobic gasket maker and just use that instead of the actual gasket. Don't use RTV here, sometimes it takes a long time to get those jugs on and the anaerobic does not set up until everything is torqued down.

[IanDMacDonald]

Wow, u were determined to find the cause of that noise, ehh? I have a noise on my bike that is very discomforting. I do believe it is worse than others make it out to be.