Author Topic: That old stinkin cam chain adjustment 78 550K (Read 1832 times)

ugmold · « **on:** April 05, 2009, 04:13:04 PM »

Here in Mass it is about time to get back on the road. Still trying to do a proper cam chain adjustment, but still scratching my head. I have it TDC 1-4, loosened the lock nut, didn't see anything happen. Took the lock nut off, sprayed same penetrating oil in/around screw, put a screwdriver on the screw and can move the screw less than 1/8 of a turn clock wise, wouldn't and then it would spring back to where it was (felt spring loaded) Won't move counter clock wise at all. Tapped it with a rubber coated wrench, nothing?

What does this mean? Any fix?

Thanks a lot.

-Ugmold

punch455 · « **Reply #1 on:** April 05, 2009, 04:29:44 PM »

I think the adjustment should be made when cylinder #1 is at TDC on its compression stroke, not just at TDC. Is that right?

OldSchool_IsCool · « **Reply #2 on:** April 05, 2009, 04:32:38 PM »

It is spring loaded, and self adjusting. My Haynes manual says to turn the crank 15 degrees past TDC 1.4, (spring post in the window) loosen the lock nut, let it self adjust, then lock it down again. I read a post from BrianJ (I think) who said to put a spanner (aka wrench) on the crank nut and hold static clockwise tension (just under the pressure needed to actually move the crank) and tighten the lock nut.

What makes you think the tensioner is out of adjustment?

ugmold · « **Reply #3 on:** April 05, 2009, 04:41:13 PM »

The reason I want to adjust it is noise. When the bike is unused for a couple of weeks you can here the chain pretty good, if you use the bike frequently you can hear it, but it doesn't seem as sloopy at start up.

I will try 15 degrees past TDC. Should I snug back up again, Turn 15 degrees then try again?

Thanks

JS550 · « **Reply #4 on:** April 05, 2009, 04:51:59 PM »

It has to be @TDC + the 15 degrees ,on the compression stroke. Take the tappet covers off of #1 & make sure you can move both , ex. and int., rocker arms. They should just be a little slack, if one side is tight, you're 180 degrees off & need to rotate the crank around again.

OldSchool_IsCool · « **Reply #5 on:** April 05, 2009, 04:56:00 PM »

Leaving it loose should be OK if you are turning the engine by hand. Definitely want it tight if you are running it.

Here is what the tensioner looks like (if you've never seen one outside the engine). Everything in box #3 is on the other side of the lock nut. The bow (#5) is metal backed hard rubber. There is a spring in the tensioner frame that tries to squeeze the bow (i.e. pushes it out). The stud you see 2/3 of the way from the top is where the lock nut fixes. It's actually a rack and pinion that, whne you turn the screw counter clockwise will draw the bow in. At least, that's how it is supposed to work.

ugmold · « **Reply #6 on:** April 05, 2009, 04:59:26 PM »

Good explanation OSIC,

Maybe mine is maxed?

-ugmold

OldSchool_IsCool · « **Reply #7 on:** April 05, 2009, 05:14:44 PM »

Hard to say. I just replaced my entire assembly because the rubber bow had deep groves in it and a few chunks missing. Also the rack and pinion was shot. I didn't know this until I pulled it out during a top end rebuild. The one symptom I did have previous to the rebuild was that I could turn the adjuster screw and it would just spin. No tension on it what so ever. This of course was the chewed up rack no longer engaging with the pinion gear on the end of the adjuster screw.

How many miles on your engine? Do you have any other reasons to open 'er up (oil leaks, poor compression, etc)?

ugmold · « **Reply #8 on:** April 05, 2009, 05:40:24 PM »

19,500 on the bike. I bought it not running a year ago. Spent my time on the carbs, pretty much .

It seeps a bit of oil, running mobil1) Runs, ocasional dead spot on acceleration, but I can commute on it.

Tried turning the crank with a socket wrench and the screw did nothing.

-ugmold

BlindJoe · « **Reply #9 on:** April 05, 2009, 06:34:14 PM »

I just adjust it while it idles; done adjusting when the engine is quietest.

fastbroshi · « **Reply #10 on:** April 06, 2009, 08:59:51 AM »

I had the head off of mine and my adjuster was FUBAR'ed, so I replaced the tensioner assembly and the blade. I would put the motor on the compression stroke, 15 degrees past tdc, and hold the slotted stud, screw, whatever you want to call it TIGHTLY counter clockwise, so you're holding it the opposite way of the direction you're tightening the nut. The motor ran very quiet this way, but only for a short time. No cam chain noise whatsoever.
It would start making noise after a bump start or any shenanigans on the road. I'd have to get down and adjust it after this, happened maybe 3-4 times. I then took the advice of a member here and tensioned it only slightlywhile tightening the nut, and it's sounded the same until now. My guess is this is correct. I haven't noticed any difference in the sound for about 1,000 miles, but it's probably time for adjustment now, have to check my manual.

ugmold · « **Reply #11 on:** April 07, 2009, 06:02:24 AM »

So, is the slotted screw suppose to be able to turn? How do you know what 15 degrees past TDC?

-ugmold

ugmold · « **Reply #12 on:** April 07, 2009, 08:16:11 AM »

Another thought, can I take the "valve cover" off and take a link out of the chain?
-ug

bryanj · « **Reply #13 on:** April 07, 2009, 09:22:58 AM »

Don't care what others have done YOU AINT SUPPOSED TO TURN THAT SCREW WITH ANY TOOLS.

No you cant remove a link and having done these bikes for too many years to count for both a living and my own i 100% guarantee you that if you follow the method i wrote up and it dont work you need a new chain and/or tensioner

ugmold · « **Reply #14 on:** April 07, 2009, 09:54:06 AM »

That's how I like my answer. Err, where did you right it up? Link?
Thanks much.
-ugmold

bryanj · « **Reply #15 on:** April 07, 2009, 10:20:57 AM »

In the FAq's under Engine FAQ's scroll down till you find it

fastbroshi · « **Reply #16 on:** April 07, 2009, 06:51:38 PM »

Let me clarify what I wrote. I didn't mean to crank away on the slotted screw (which I did the first time). Just to hold it and keep it from turning when you tighten the nut. Does this require some torque? Yes, to tension the nut.

ugmold · « **Reply #17 on:** April 08, 2009, 10:25:04 AM »

bryanj,

How do I know when I'm 15 degrees before TDC on #1.

Thanks,
-ugmold

drackett_19 · « **Reply #18 on:** April 08, 2009, 10:51:53 AM »

Here is a link to a cb550 service manual: http://www.sohc4.net/files/HSMCB500550.pdf

Pages 12 and 13 describe the process and there are pictures of where the timing marks should be for 15 ATDC.

ugmold · « **Reply #19 on:** April 08, 2009, 11:26:02 AM »

Thanks much

ugmold · « **Reply #20 on:** April 16, 2009, 01:13:22 PM »

Took for a ride today, started right up. And guess what? No cam chain noise!!!

After I adjusted the valves that were a little tight, I followed the "Bryanj" instructions and it seemed to work. I would isolate this as its own FAQ in the FAQ section. Might save a lot of frazzled brains.

Hats off to Bryanj.

Bike does run better as well.

-ugmold

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Author Topic: That old stinkin cam chain adjustment 78 550K (Read 1832 times)