Cam chain too tight won't slacken

[Quilty]

After trying to locate a whirring noise in my engine. I have come full circle and ended up back at my cam chain. I had originally dismissed it as the cause of my problem because it was or seemed to be spot on. I.e pin flush with the end of the bolt and 1-2 mm movement. after looking elsewhere clutch, kickstarter,bendix assembly and cam shaft I have eliminated them all and have been pointed back to the cam chain as the possible cause of my whirring.
I decided to adjust the cam chain again first by loosening the chain with the bike running looking for the clack clack sound of a loose chain and then tighten it from there and I was able to unscrew the adjuster bolt nearly out of the bike without any change in sound. I turned the bike off and removed the chain tensioner rod, spring and bolt and there are no signs of damage or wear. Using the rod as a feeler I tried to push the other end into the engine to see what was going on. No give or slack. It all seems to be tight as a drum and the cam chain adjuster has no effect at all. What am I looking for if I am looking to diagnose this as my whirring noise?

Stock 72 xs2 type B tensioner

 

[CDNTX650]

Is it a new chain? New ones won't have much slack.

 

[TwoManyXS1Bs]

Sounds like it's time to spend some time with a mechanic's stethescope.

Ever use one?

 

[chizler62]

What whirling means to you not be whirling to me. Typically a whirling sound to me is a broken tooth off a primary gear. You see this a bunch when kids try to replace their clutch on a 2-stroke and use a screwdriver to bind the primary gear and clutch gear to loosen clutch basket.

Video it with sound?

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[Quilty]

Yes the chain is new-ish about 1500 miles on it. I have a stethoscope and I've listened to it. It was loudest at the bottom near the kickstart so I pulled it out and had a look. All good. I also removed the no 4 gear assy and left it out so I'm kickstart only I rebuilt the clutch and checked for rubbing behind it. Not loud enough to be bottom end crank I will post a video

 

[Quilty]

Cold morning start with choke. It idled for about 4 mins before I took the video. Choke off. Valves are good carbs are off a 77. Let me know what you think and thank you as always

 

[gggGary]

First chain tension. depending on the position of the crank/valves the rear run of chain can be under tension from a valve spring working against a cam ramp. That whir (hint; shut up and hold the camera steady for a bit) sounds an awful lot like a spreading lower crank to me, sorry. Slight side loading on ball bearings can cause a whir that could stay fairly steady for quite a while.

 

[TwoManyXS1Bs]

Here's a deep rabbit hole. Maybe some ideas in here:

http://www.xs650.com/forum/showthread.php?t=23162

 

[Quilty]

Man that is a rabbit hole. I've been lost in it for 2 days now. At least I finished it which is more than I could say about zen and the art of motorcycle maintenance. I am dreading having to take the engine out and opening it up. I know the po did a full top end 1500 miles ago if I believe him or not. Looks like I'll have to do the bottom. What did I sign up for. At least it's easier than a harley

 

[TwoManyXS1Bs]

Man that is a rabbit hole. I've been lost in it for 2 days now....

Aaaaahahaha, LMAO!

Thanx, Quilty, that made my day!

Yeah, that thread's definitely a book.
Hope it made sense, gave you some ideas, and didn't disturb your life forces too much.

 

[Quilty]

Are there any threads on here on splitting the cases without removing the heads or disturbing the top end. And can I get at the transmission / camshaft bearings aswell or do I have to remove the rocker box and remove the cam chain. This is my first bottom end on any bike but I'm glad its an xs.

 

[5twins]

Do a search and find out. I really don't see the need for one though. You simply follow the manual instructions. What you do need to know though is that these motors split upside down. You remove the bottom case half and all the gears and the crank remain sitting in the upper case half. So, what you need is a way to prop the engine up turned upside down .....

Since everything remains in the top case half, you can crack the crankcase open with the topend still intact. You won't be able to access the camshaft bearing though. That will require a topend teardown.

 

[Quilty]

Did I say camshaft I meant to say crankshaft bearings. Thanks for the reply 5twins nice pic btw

 

[5twins]

Yes, you will be able to get at the crankshaft bearings with the bottom case half off. However, I'm not sure if they're a slip fit on the crank or pressed on.