Author Topic: cb550 cam chain tensioner help (Read 5224 times)

Mitchell · « **on:** February 17, 2016, 06:37:04 AM »

Ok so last night i was getting my new project 550 ready to run valves adjusted, points adjusted and timing set with a test light and then i was going to adjust the cam chain tension. Well got the motor 15 degrees past tdc on number 1 tried to break the lock nut loose without the adjuster acrew turning. I could not get it to come loose so i did a quick jerk on it and it came loose but the adjuster screw turned with it, now the screw will only turn maybe an 1/8 turn in either direction with no spring tension on it, if i turn it left it stays left if i turn it right it stays right. Now i guess im asking if anybody had this happen before and how bad is it? Will i need to pull the head to get the chain tensioner out if it comes to that? Any help would be greatly appreciated.

flatlander · « **Reply #1 on:** February 17, 2016, 07:44:07 AM »

the screw does not turn 360 degrees if that's what you mean. it has a little bit of play either side. but you don't actually use it for adjusting tension.

for adjusting: the tensioner is spring-loaded and self adjusts when the nut is loosened. the screw does not need to be turned for this. after adjusting tension this way, you just lock down the nut again holding the screw in the position it's in.

this is described in the honda shop manual, hope you have one?
if the tensioner and your cam chain are in good enough shape then it will work and i don't think you need to worry.

Mitchell · « **Reply #2 on:** February 17, 2016, 08:10:20 AM »

thats just it the screw is not suposse to turn but it did when i broke the lock nut loose now it seems to be in the wrong position or something. There is no spring tension on the screw i can move it around with the tips of my fingers only about 1/8 turn and thats it, no spring tension what so ever on the screw and when i turn it till it stops there is no give on the screw like a spring would do, stops and does not move any. I hope all of this is making since.

wowbagger · « **Reply #3 on:** February 17, 2016, 08:49:45 AM »

If the screw moved when you loosened the lock nut, that was the spring tensioner self adjusting. It should now be in the correct position. Just tighten down the lock nut again.

Mitchell · « **Reply #4 on:** February 17, 2016, 08:57:47 AM »

I hope thats it, but it didnt move with the spring the lock nut and screw were stuck together so tight the flat tip screw driver would not hold the screw so the lock nut forced it to turn not the spring

wowbagger · « **Reply #5 on:** February 17, 2016, 09:07:46 AM »

If you are really concerned about it, you could pull the cam cover and check the tension on the cam chain.

That bolt just pinches the metal slide that the tensioner is attached to. Loosening the lock nut lets the spring retract which bends the tensioner tighter against the chain. The angle of the slot in the bolt does not matter. At least, not as I understand it.

Mitchell · « **Reply #6 on:** February 17, 2016, 10:18:27 AM »

Guess i will be pulling the cam cover something just dont seem right

Mitchell · « **Reply #7 on:** February 17, 2016, 10:27:11 AM »

Mitchell · « **Reply #8 on:** February 17, 2016, 10:32:21 AM »

does that seem normal?

wowbagger · « **Reply #9 on:** February 17, 2016, 10:45:33 AM »

Ok, I was wrong. The later model tensioners are the ones that just pinch the slide. These do rotate that bolt to tensions it. See:

However, your video doesn't look like an excessive amount of play to me given the total rotation that the bolt is capable of.

Mitchell · « **Reply #10 on:** February 17, 2016, 10:56:42 AM »

In the video i put up you can see how far it turns thats it it will not budge past those stoping points

flybox1 · « **Reply #11 on:** February 17, 2016, 11:31:19 AM »

Can you take the lock nut off and clean the threads?
It may not go IN because of a little corrosion on the threads.
Shoot a little PB blaster there to see if it will wick into the threads and allow it to turn freely..
Heat helps, too

watch this

Mitchell · « **Reply #12 on:** February 17, 2016, 11:38:59 AM »

Good plan flybox i will give that a try. But with that said the nut will screw right off and the screw will wiggle around when the nut is not tight.

flatlander · « **Reply #13 on:** February 17, 2016, 11:47:34 AM »

do you have the o-ring underneath the nut, and then the washer? it should be, starting from the cylinder block: o-ring, washer, nut.

flybox1 · « **Reply #14 on:** February 17, 2016, 11:49:01 AM »

its supposed to wiggle...its a self adjusting unit, but the screw should be able to rotate freely (watch the vid)

Mitchell · « **Reply #15 on:** February 17, 2016, 11:58:50 AM »

Good info i will need to look for the oring the washer is there but i didnt pull it off and look behind it, the oring may not be there
Flybox i watched the video, you see how when you rotate the screw a bit you can see the spring tension rotate the screw to where it needs to be, mine is not doing that it has no spring tension on the screw. If i rotated it left it just stays if i move it right it just stays and it will only move that little bit in that video i posted no more.

flybox1 · « **Reply #16 on:** February 17, 2016, 12:08:30 PM »

Quote from: Mitchell on February 17, 2016, 11:58:50 AM

Good info i will need to look for the oring the washer is there but i didnt pull it off and look behind it, the oring may not be there
Flybox i watched the video, you see how when you rotate the screw a bit you can see the spring tension rotate the screw to where it needs to be, mine is not doing that it has no spring tension on the screw. If i rotated it left it just stays if i move it right it just stays and it will only move that little bit in that video i posted no more.

. . precisely why I suggested a little PB blaster on the threads so you can break past whatever is preventing it from turning clockwise, and get it to where it is tensioned.

Mitchell · « **Reply #17 on:** February 17, 2016, 12:15:04 PM »

Gotcha going to try it as soon as i get home. This very well could be the problem this bike has been sitting for awhile

flatlander · « **Reply #18 on:** February 17, 2016, 12:31:33 PM »

Quote from: Mitchell on February 17, 2016, 11:58:50 AM

Good info i will need to look for the oring the washer is there but i didnt pull it off and look behind it, the oring may not be there

in your vid it looks like the o-ring is there, directly under the nut. or is it some (wrong) small diameter, thick washer? of course i might be wrong as the picture is a bit small and sometimes unsharp. but it did not look right to me.

flybox is right, it might just be a bit stuck. don't force the screw too much with the screwdriver or you'll brake it, just use some penetrating oil and wiggle it around a bit.
with the nut on but loose, you can also try pushing the screw in a bit and pulling it out again. leave the nut on because if you push it in all the way it will be a pain to get out.

Mitchell · « **Reply #19 on:** February 17, 2016, 12:38:56 PM »

Thanks guys i really do appreciate it. Its a washer behind the nut in the video and yes it does seem kinda thick, im new to the 550's so im not sure exactly what it should look like

flatlander · « **Reply #20 on:** February 17, 2016, 01:00:14 PM »

the video that flybox posted shows the correct washer. get a partslist (or look it up on cmsnl.com) and order the correct o-ring and washer. don't know what's underneath that non-original washer that you have there, but it might be part of the problem.

Mitchell · « **Reply #21 on:** February 17, 2016, 01:02:08 PM »

Will do thanks i will report back as to what i find behind the washer

bwaller · « **Reply #22 on:** February 17, 2016, 01:23:30 PM »

There should be a thicker than normal 6mm washer, I think you have the right one. You can add a second one and not do any harm if you think the nut is bottoming out. However I think you may have over extended the adjusting screw and possibly stripped or bent the mechanism. Because of the spring on the tensioner that adjusting screw should return to a center like in one of the vids.

Try all the other positive suggestions first of course. To replace the tensioner assembly you need to remove the cylinder head and raise the cylinders a 1/2" or so. Of course when you do that the base gasket will need to be replaced so you can see where this is going.

I don't mean to be the bearer of bad news. Good luck.... I hope I'm wrong.

Mitchell · « **Reply #23 on:** February 17, 2016, 02:22:54 PM »

bwaller thanks i hope your wrong too! but its very possible thats kinda what i was thinking something got bent. so say i do need to pull the topend would it be safe to get it cranked and drive it to see if it goes through all the gears properly and is not knocking like hell before i pull it? I really dont want to pull the topend put new gaskets in just to find out ive got a boat anchor. Ive never heard this bike run picked it up about two weeks ago in boxes.

jonda500 · « **Reply #24 on:** February 17, 2016, 05:03:44 PM »

Hi Mitchell, here's a picture of the tension mechanism - hard to see as it's behind a little plate - it's basically a miniature rack and pinion. This one had some bent teeth on the 'rack' part - I had to bend out one of the tabs that hold the little plate on (the plate stops the screw from being able to push in when the lock nut is removed!). With the little 'H' shaped plate removed I was able to straighten out the bent teeth, reinstall the plate and bend back down the tab. This sounds like what is wrong with yours.
The spring pulls the ends of the tensioner together bowing it in to the chain thus taking up the slack. Turning the screw clockwise pulls the ends apart which stretches the spring and releases the tension by straightening out the bow in the tensioner.
Running it with no tension on the chain just to check the engines state would take a long time to do any harm or damage that matters to the engine in my opinion, John

bwaller · « **Reply #25 on:** February 17, 2016, 06:58:17 PM »

Just don't rev the thing too high. If the tensioner... isn't ...the chain may be very loose. If so it'll rattle in the top end and you'll know.

Duanob · « **Reply #26 on:** February 17, 2016, 07:50:16 PM »

I found that the Honda instructions for the adjuster nut on old corroded dirty threads aren't good enough. Honda says the nut will self adjust on it's own but I find I get a tighter adjustment with a bit of tension on the adjuster screw. Get yourself a 90 degree flat blade screw driver and a 10mm box wrench. It takes a bit of fiddling but put the box wrench on the nut where you can tighten it and loosen it without removing it. Then loosen the nut and with the screw diver put some pressure on the adjuster, counter clockwise and tighten the nut. Don't crank it just put pressure on it. The nut will turn with the adjuster a bit but the tensioner will be as tight as you can get it. Start the bike up and see how quiet it runs ( relatively, 550s aren't the quietest valve trains).

Mitchell · « **Reply #27 on:** February 18, 2016, 06:18:13 AM »

Thanks guys i really do appreciate it! Well i i twisted and turnd pb blastered and lots of cuss words and could not get it right so pulled the topend and jonda500 hit the nail on the head the teeth were all bent up

Mitchell · « **Reply #28 on:** February 18, 2016, 06:22:14 AM »

Here it is after a little love. I was also glad to see a very clean motor on the inside with very little carbon build up.

strynboen · « **Reply #29 on:** February 18, 2016, 10:33:58 AM »

nice to see a real life tensioner..

.
.most just guess how it Work..i vill like to have a real handel at the end..to finger adjust..to help the spring...but the idea of the spring system is to leave it to the spring.
.and instead place the cam,,,so it balance aut any slock..before the kontra sckrev are turned inn..

flatlander · « **Reply #30 on:** February 18, 2016, 11:26:29 PM »

great that you found and fixed the problem!
now when you put it back in, make sure the bottom end of the tensioner properly sits in its place, before you tighten down the head.

Mitchell · « **Reply #31 on:** February 20, 2016, 12:22:54 PM »

Flatlander thanks for the tip, that would have probably been my next mistake.

alacrity · « **Reply #32 on:** March 03, 2016, 07:24:22 PM »

Quote from: Mitchell on February 20, 2016, 12:22:54 PM

Flatlander thanks for the tip, that would have probably been my next mistake.

yeah what Flatlander said. It's REALLY easy to shove it down into the receiver in the case and... well look at the end of the tensioner -- see those two little spring-off "arms" at the sides? These provide a bit of side-side movement control as natural spring levers. BUT if you shove the tensioner it at a tiny bit of an angle and just think, "Oh well the slot is a snug fit, so I'll add a couple lbs. of muscle," what can happen is one of those little arms can snag on the top lip of the slot, and bend outward... and if its the side where the primary chain whirls right by about 1/4" to the side of it, well, you can imagine what ensues....
To ensure this doesn't happen, drop the drain pan, position the adjuster properly since you can now see it slide into place

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Author Topic: cb550 cam chain tensioner help (Read 5224 times)