Author Topic: Video - help identify engine noise (Read 4003 times)

FlipYa4Fake · « **on:** June 28, 2015, 06:37:42 PM »

1981 CB650C. I just changed all the top end gaskets and now the bike is finally back together. This is my first time starting it since putting it back together. I am so happy it started, but I have this loud clacking noise. Sounds like maybe the cam chain hitting? Do I need to do something with the tensioner? What are my next steps here? Should I stop starting it because I may be causing damage? Please let me know if further info is needed. Thanks.

Tews19 · « **Reply #1 on:** June 28, 2015, 08:07:57 PM »

Cam chain installed incorrectly?

FlipYa4Fake · « **Reply #2 on:** June 29, 2015, 05:35:43 AM »

Can you elaborate on installed incorrectly? I am not sure what could be incorrect about it. I put the cam shaft through the sprocket, put chain on the sprocket, and torqued the sprocket in the cam shaft. Don't know how I could go wrong there.

Tews19 · « **Reply #3 on:** June 29, 2015, 05:47:07 AM »

Dave 500 made a post on here. You can install it upside down. Let me look for thread and will link it.

DaveBarbier · « **Reply #4 on:** June 29, 2015, 05:50:08 AM »

Quote from: FlipYa4Fake on June 29, 2015, 05:35:43 AM

Can you elaborate on installed incorrectly? I am not sure what could be incorrect about it. I put the cam shaft through the sprocket, put chain on the sprocket, and torqued the sprocket in the cam shaft. Don't know how I could go wrong there.

For the 650 the motor has to be at 1-4 TDC. Verified by looking through the peep hole on the ignition plate. The cam has an index mark on the right end (the #4 cylinder end) and it has to be aligned with the cylinder head surface.

This is my 550 but the procedure is the same for the 650.

If you didn't do this, DO NOT run your motor anymore. Crack it open again and adjust. Might want to check if a valve has been bent, too.

FlipYa4Fake · « **Reply #5 on:** June 29, 2015, 07:10:55 AM »

Thanks Dave. I did follow that process. I had the marker on 1-4 and the index marker on the cam shaft level with the cylinder head. May be off a small bit. Like a couple millimeters. Sounds to me like tear back apart for third time. I did crank the cam chain tensioner a quarter turn and seems to sound better. Will do quick follow up video after work

DaveBarbier · « **Reply #6 on:** June 29, 2015, 07:28:05 AM »

Oh ok, cool. The cam won't be exactly lined up with the surface of the head. If you're a tooth off then it won't be even close to aligned. Sounds like that's not your problem. I would wait on the removing the valve cover. Could be tappet adjustment?

FlipYa4Fake · « **Reply #7 on:** June 29, 2015, 06:19:16 PM »

Here is the follow up video. I removed the covers and I am turning the crank with a ratchet. It has compression and then all of a sudden it turns very easy for about 1/16 of a turn and that's where I hear the click. I also can hear the sound of losing air. A thunk sound. I also took a picture of the plate to show where in the rotation it is happening. It starts at the gap spot and ends where the picture is. I hope someone can identify the issue so I can fix and move forward. Thanks

Tews19 · « **Reply #8 on:** June 30, 2015, 04:55:17 AM »

Man I'm lost. As far the the first video you can see a valve cover nut loose. The washer was vibrating as well as the nut. Are you sure everything was tightened? Also when you aligned the cam notch with the chain was number one cylinder in the correct space?

FlipYa4Fake · « **Reply #9 on:** June 30, 2015, 05:49:47 AM »

In a previous thread I mentioned that two of the valve cover bolts wouldn't tighten. I will have to address that. I will take the valve cover off tonight and give some turns again. I will take pictures of the marker on the cam shaft and on the plate to show position.

DaveBarbier · « **Reply #10 on:** June 30, 2015, 10:21:38 AM »

Doesn't say in the manuals, but I've been told many times to use rubber bands to hold the tappets off the valves when removing or installing valve cover or you could bend valves.

scunny · « **Reply #11 on:** June 30, 2015, 10:51:44 AM »

did you seat the bottom of the cam chain tensioner properly in it's holder. very easy to get wrong and then you can't tension the cam chain.

FlipYa4Fake · « **Reply #12 on:** June 30, 2015, 12:05:15 PM »

Quote from: DaveBarbier on June 30, 2015, 10:21:38 AM

Doesn't say in the manuals, but I've been told many times to use rubber bands to hold the tappets off the valves when removing or installing valve cover or you could bend valves.

Interesting. I will have to try that. I am taking the valve cover off tonight and will report on any new findings. Thanks for all the comments and feedback

Tews19 · « **Reply #13 on:** June 30, 2015, 01:46:53 PM »

Quote from: DaveBarbier on June 30, 2015, 10:21:38 AM

Doesn't say in the manuals, but I've been told many times to use rubber bands to hold the tappets off the valves when removing or installing valve cover or you could bend valves.

Rubber bands are a must to prevent any valve damage

FlipYa4Fake · « **Reply #14 on:** June 30, 2015, 04:12:39 PM »

Ok. Removed the cover. I did not do rubber bands as I was unsure of the process. I will need to research how to do this for install. Please see the pics below and let me know if I have the correct marker on the plate for where the camshaft is. Do you think it is off a tooth? Definitely too much slack in cam chain as shown. I will keep posted.

Tews19 · « **Reply #15 on:** June 30, 2015, 04:17:18 PM »

The notch pic is really dark but if I'm looking at the nipple for the timing you look to be off a tooth or two. Wait till someone else chimes in.

FlipYa4Fake · « **Reply #16 on:** June 30, 2015, 04:21:18 PM »

Follow up: I loosened the set screw (bottom screw) of chain tensioner. I then loosened the top bolt (counter clockwise) and that adds more tension to the cam chain? Feels real tight now. Was that my problem the whole time that I had the top screw all the way tightened?

I will take a better pic

DaveBarbier · « **Reply #17 on:** June 30, 2015, 04:25:29 PM »

Actually put it at the T mark for the next picture. It's a little off and hard to tell if the cam is off a tooth or not. But it looks ok to me since they're both (points plate and cam notch) a little off.

FlipYa4Fake · « **Reply #18 on:** June 30, 2015, 04:30:43 PM »

This is right at the T

DaveBarbier · « **Reply #19 on:** June 30, 2015, 04:33:10 PM »

If that IS right at the T mark for 1-4 then it looks like you're off. Moving even one notch makes the cam move quite a bit, though. But I'd go ahead and move it forward one notch and see where you are.

EDIT: Throw some rags in the cam chain tunnel so you don't loose a sprocket bolt. That would be quite crap.

FlipYa4Fake · « **Reply #20 on:** June 30, 2015, 04:52:51 PM »

Thanks I will move it a tooth over. Any thoughts on cam chain tensioner question a few posts back?

DaveBarbier · « **Reply #21 on:** June 30, 2015, 06:13:20 PM »

The small bolt in the head for the cam chain tensioner should be tight. That and the notch at the bottom inside the case are what hold the tensioner in place.

Tews19 · « **Reply #22 on:** June 30, 2015, 06:18:19 PM »

Take your time Flyp. You don't want to rush this type of work and the littlest error may cost you dearly.

Scott S · « **Reply #23 on:** June 30, 2015, 06:19:03 PM »

Quote from: scunny on June 30, 2015, 10:51:44 AM

did you seat the bottom of the cam chain tensioner properly in it's holder. very easy to get wrong and then you can't tension the cam chain.

This.
Plus, it looks like you may be off by a tooth or two.

DaveBarbier · « **Reply #24 on:** June 30, 2015, 07:55:06 PM »

Here's a picture from Dave500's 500 I think. It shows a wrongly seated tensioner. You might be able to see it in the 650 if you remove the oil pan.

Here's a picture of my 550. If you were to remove the tensioner, this is the holder/notch/slot thing it needs to fit into.

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Author Topic: Video - help identify engine noise (Read 4003 times)