The great camchain debacle of 2012, rotated engine CCW during cam chain adjustment

[Majortomxx]

Hey everyone, I’ve been reading this form for quite a while and decided there was no better place online to take this issue.

I have a 1980 XS 1100 special, it’s my first bike. I’m in the process of restoring it after neglectful riding for about 2 seasons.

I recently attempted to adjust my cam chain for the very first time. I followed the instructions in the manual: rotate the engine clockwise till the stationary marker and the C on the timing plate line up, (no plugs in) loosened the 10mm bolt, then the 12mm locknut. The manual said to just tighten them back up but nothing seemed to happen before or after.

I figured “well ok, the manual said that’s all I needed to do…” and closed everything up, started up the bike to this wicked clatter, like a metal can full of change in a paint shaker, the bike ran about a half second before I killed it, it wanted to stall anyway.

At this point everything gets bad, I panic a little and go back over the instructions. Perform the steps again after searching the net, but this time I rotated the engine clockwise a little and found resistance, the bike didn’t want to turn anymore and I didn’t force it. With the bolt and locknut on the adjuster still loose I turn the engine counter-clockwise just a little, away from the resistance. I cringe and hear this little *pl-plink* sound at the front of the engine. I look at the cam chain tensioner and that little black part from the front is gone, leaving what looks like en open Allen bolt.

I don’t know what the metal clinking sound was, but I have a sick feeling some part of the adjuster came loose in the engine case. It was getting dark at this point so I didn’t take the valve cover off to look at the chain, nor did I look for the stopper. I decided it best if I got some guidance before jumping in there again.

So my questions are:

Why, after following instructions to the letter did I have a clattery sound in the top end? I know I did something wrong, otherwise I’d have less engine noise and a better running bike, not more and worse.

What damage could have been caused by rotating the engine counter-clockwise with the tensioner bolts loose?

How do I tell if I’m missing part of the tensioner, and if I am, what is the best way to retrieve it?

I feel like a total dolt but I really want to fix this, any help here would be great. I know I should’ve waited and asked some questions before acting, if anything this has been a lesson in patience.

Thanks.

[WMarshy]

Did you perform the adjustment with the bike on the center stand on level ground? From what you described everything was done correctly. The only possible explanation is the adjuster slipped when you started the bike... pretty sure of it unfortunately, which would explain why the plastic cap in the end of the adjuster ejected (slammed the adjuster outward hard enough). This is why the ratcheting style auto tensioner is so highly recommended. Your next step is to check for valve damage. Your best best is to take the cover off and check valve to shim clearance on any and all valves that have the lobe up. Do not rotate the engine at all, either by hand or definitely not with the starter. Sorry dude, you got a big problem on ypur hands.

[TopCatGr58]

Hey there Major,

We'll see if I'm actually the first to respond, others may be typing at the same time I am!?

Okay, the cam chain tensioner is a known problem device, and depending on how PO's have treated it, it may have been previously overtightened and therefore the threads in the housing possibly partially stripped! It was holding prior to you working on it, but STUFF happens. After releasing the locking BOLT, sometimes you hear a click, usually not if there wasn't much slack that would have developed in the chain since the last adjustment. But then you needed to reset/tighten the lock BOLT first to the proper LOW TORQUE level to secure the tensioner plunger in the housing so that it would not move. Then you would lock the locknut around the bolt to keep it from backing out/loosening. But it's this setting the lock bolt tension that things can go awry....ie. too tight, which can strip the threads in the housing, and so then the bolt actually is NOT TIGHT against the plunger. So then when you run the engine, the plunger does NOT maintain the chain tension, it pulses in and out as the chain SLAPs around in the engine...the noise you heard when it was running, and sometimes enough slack can occur that the chain can skip a tooth on the crank sprocket and get the valve timing out of time, which can then result in valves hitting pistons!

Rotating the crank backwards...with the plunger not being held secured allowed the slack to then get taken up by the crank sprocket which then pushed the plunger outwards and is probably what caused the end plug to pop out.

SO....you will want to take the gas tank off, pull the valve cover off, and the safest thing will be to take the cams out, but it's kind of difficult to do when you can't rotate the engine, because you can't reach one of the 2 bolts for the cam chain sprockets on the cams! However, with the cam chain tensioner loose.....might as well just remove it from the engine, then you'll have possibly enough slack to be able to remove the exhaust cam first, and be able to slip the chain off of the sprockets without having to remove the sprockets from the cams or rotating the engine!

Attach a bungie to the cam chain to keep tension on it during and after you remove the cams, to keep it up around the crank shaft sprocket. Be sure the bike is on the centerstand before working on it. Also have the plugs out. Once you get the cams out, you can then safely rotate the crank around to the "T" mark to prepare to reinstall the cams with their alignment dots at 12 o'clock and in line with the alignement arrows on the cam caps. Keep the cam bearing caps in order, so that they go back in the same place they were. Stuff rags down inside the cam chain tunnel when handling the cam cap washers/nuts so that you don't drop one down there!

Might as well get on eBay and find your self a self adjusting Cam Chain tensioner to replace your OEM unit...search the site for ACCT, you'll find the info of the various models that interchange so you can find a relatively cheap one!

Due to the valve spring tension on at least one valve you will not be able to put the washers and nuts on ALL of the cam caps/bolts at the beginning of reinstalling the cams, you usually have to slowly tighten the other caps a turn or so each which will slowly compress the valve spring that is high, and will then allow enough clearance to be able to put the washer/nuts on the bolts to get them started so that you can then tighten them down to get the cam even/flat across. Get an inch pound torque wrench because they only take 7 ft/lbs, which is ~84 inch/lbs. Regular torque wrenches are not sensitive enough and you'll strip these nuts/bolts also!!

Once you have the cams in with the dots aligned and the crank on "T", you can then put in the new ACCT, set it, and THEN you can rotate the engine a couple of turns and recheck the timing marks....and IF they are still aligned, then you can check your valve clearances looking for any that are excessive....which could then indicate a bent valve! If the clearances are within or close to spec, then you can do a compression test as another check to see if the valves got bent. We know that a cold test isn't as good as a hot one, but you have to work with what you have. Then if you have even compression on all 4, then you can "assume" that you have NOT bent any valves, put your valve cover back on, plugs in and fire it up!

IF the valve clearances are way off, then you'll be taking it back apart and inspecting for bent valves and replacing any you find!

Good Luck!

T.C.

[ViperRon]

One check you can make after you have taken the cams out it to check for bent valve without pulling the head. The way to do this is by hand only do not use the starter. make sure bike is setting level. Support the cam chain so that it does not bunch up but can be spun in the engine. Usually using 2 pieces of PVC pipe will work.

Take all 4 plugs out. Slowly by hand rotate the engine ccw watching the cam chain and make sure it moves freely. Now put a finger over one spark plug hole at a time and rotate the engine ccw. On the down stroke a piston should suck your finger in and on upstoke push your finger out. If the cylinder does not suck or push then you probably have a damaged valve.

Please use caution doing this and support the cam chain as you do not want it to get get bunched up in the engine. Do not use the starter !!!!!! it could bunch the chain and break all kinds of things or possibly suck your finger into the plug hole so tight you get injured.

This is just a quick check for valves before putting all cams in.


Final check and reasembly per TC's message will get you where you need to be.

[WMarshy]

I followed the instructions in the manual: rotate the engine clockwise till the stationary marker and the C on the timing plate line up, (no plugs in) loosened the 10mm bolt, then the 12mm locknut. The manual said to just tighten them back up but nothing seemed to happen before or after.

I figured “well ok, the manual said that’s all I needed to do…” and closed everything up, started up the bike to this wicked clatter, like a metal can full of change in a paint shaker, the bike ran about a half second before I killed it, it wanted to stall anyway.

Thanks.

By no means am I trying to insult you but, when you adjusted the tensioner the first time did you tighten the set screw befor tightening the nut..? If so, did you use a torque wrench or just litghtly snug it? The only reason I ask is because order of operation is important and you wrote you losened the bolt before the nut...(sorry the devil is in the details).

[natemoen]

Once you have the cams in with the dots aligned and the crank on "T"

AND the cam sprockets have little marks on the lands that the bolts tighten down on. The marks look like little nipples pointing out at the sprocket teeth. Not the best description put if you look at it you will see what I mean.

Those marks need to be pointing upish (they won't be exact, just need to be on.the upward side of the cam) when the dots on the cam are lined up.

Also, justremove the spark plugs and look down each cylinder. See if you see any contact marks on the piston, valve heads, or other things in there. See if you can see which piston is getting stuck and if you can see where piston/valve contact point is (if there is).

[Majortomxx]

Thanks everyone for the great advice. This is such a huge help.

I'm holding off on any work until I have an inch pound torque wrench, something I can't seem to find today. I'll post and update when I get into the engine again, hopefully this weekend.

[trdriver71]

You can get them either at canadian tire most 3/8 drive ones they sell are, or you could also go to princess auto.

[trbig]

Take all 4 plugs out. Slowly by hand rotate the engine ccw watching the cam chain and make sure it moves freely. Now put a finger over one spark plug hole at a time and rotate the engine ccw.

Why would you turn the motor CCW???

The problem with doing this in his instance is that he may have jumped a tooth or two already on his timing. By further turning the motor with the cam chain adjuster out, it lets the timing get so far off, that there's a good chance of bending valves.. if they aren't already... not to mention a very good chance of the crank sprocket jumping a tooth. The pistons have great leverage at the top of their stroke, and even turning the motor carefully by hand, you won't feel the pistons contacting the valves and bending them, as they are very weak to sideways torques.

My best advice is to pretty much follow T.C.'s advice, only I'd pull the the cams, get the crank back in time and re-install them in time. If the cams aren't pushing any valves down, there's no danger in turning the motor. Then, you can stick your finger in the hole where the cam chain tensioner goes and push in on the adjuster bar, and turn the motor CLOCKWISE.. watching to make sure the cams are moving along with the crank. You'll have to spin the crank around twice to check that your timing with the cams is still on. If it is.. then you can check for compression with your finger over the spark plug holes, but you still need to make sure you have tension on that adjuster at any time that you turn the motor and turn it CLOCKWISE.

Doing this cam removal can be a real PITA. You have to make sure that all the slack is taken out on the back side of the motor between the crank and the intake cam. If it's loose at all, when you go to rotate the motor to check time, the crank will move until it pulls that slack out, THEN the cams will start turning. It's very very easy to get it one tooth off. You might offer up some adult beverages and charred animal flesh to see if someone who's done it before is in your area and can come help you the first time you do something like this.

[ViperRon]

Why oh WHY you do ask.

trbig you asked so I will explain. Please read completely as I do not think you read clearly what I wrote before.

1. It is a pain in the a&& big time to remove cams and go threw timming.
2. Its ever so much worse when you are not familiar and already have dred from what happened.

So what I suggested is when he takes the cams out!!!!!!!!!!!!! to do this to test and see if he has a bent valve.

My thought is why have a man unfamiliar with the process go threw the process of reinstalling cams trying to go threw alignment and possibly take the chance of bending the other valve in the exaust/intake set.

While the cams are out it is easy to support the chain with 2 pieces of pipe and with the plugs out of all cylinders rotate the engine by hand to see that there is compression in all cylinders. There is no sense in reinstalling the cams retimming the chain if a valve is already bent because you have to remove the head to repair it. Now I may be wrong but with the cams out all valves are shut and there is no chance of bending any of them. If you rotate the engine it will suck and blow but only is possible threw the plug hole. Now if you are going to turn the engine then its best to turn it CCW so that it does not suck oil out of passages and so that the timing chain is pulled across the top of the crank gear thereby limiting the chance of it bunching up.

Now it was suggested to just look in the spark plug holes to check for damage but I can not see if a valve is slightly bent looking threw the hole but I can say there will be compression from hand turning if no valves are bent.

Now after a person has already had a problem I always thought it best to find simple ways to identify how bad it is. With my test you do not have to put the cams back in risk the valve further damage to find out how bad it is and if it did not bend a valve then the guy can breath a sigh of relief and focus on just timing it correctly.

Now if my theory is off please explain it to me because my intention is to help

[BA80]

I have one question Majortom....why did you leave the spaceship?

Have you checked the timing marks to see if you've slipped time?


Can you hear me Majortom?

[WMarshy]

I have one question Majortom....why did you leave the spaceship?

Have you checked the timing marks to see if you've slipped time?


Can you hear me Majortom?

Greg, he did say that he felt there was some resistance when he tried to rotate it clockwise after the dreded noise. He would have to rotate the engine to check the timing marks...

I think the safest thing to do is to take the cams out and do a leak test on all the cylinders. You can smash the porcelain out of a spark and thread on a male connector for you compressor hose to make an adapter for the leak tester. Just hook up the air and check for leaks at the exhaust or carbs... no rotating involved, then set the crank back to T and install your cams assuming nothing is bent. Its not too bad, I removed and installed my cams back to proper timing in about 3 hours. I was nervous as it was my first time and I didnt want to mess anything up... just follow the manual and take your time. The reason it took me so long was because the dots dont line up as close as I expected so I had to check that they were not one tooth off...

[Majortomxx]

Little update...

After visiting all the hardware stores and finding noting but 0-150lb torque wrenches I wandered down to princess auto and picked up the last 1/4 inch pound wrench.

Weather permitting I'll start assessing the damage tomorrow. I'm preppared for bent valves but i don't think I'll find any (here's hoping), the resistance occurred only after rotating the engine with the chain slack. I know it doesn't take much to pooch a valve, but I was able to rotate the engine fine after firing it up.

Ateast I hope that means no bent valves haha.

So, from what I've read so far. I should take the valve cover off, remove the cams, reset the cam timing and see if I can rotate the engine CW. Encountering resistance means a valve is contacting a piston and I get to behead my bike?

Or, remove the cams. Where the cams ought to be, put two sections of pipe to allow the chain to slide over while maintaining tension and do a compression test?

Like I said, as long as its not raining I'll start this grim buisness tomorrow. Looking forward to it actually.

Edit**

Likely this all happened because the bolt wasnt tight enough on the tentioner, I have since learned you can't improvise certain necessities.

[BA80]

I suggest you go ahead and round up an automatic CCT. Those stock ones are nothing but trouble.

[natemoen]

I suggest you go ahead and round up an automatic CCT. Those stock ones are nothing but trouble.

Agreed, take the next preventative step.