Camchain tensioner housing..

[gareth]

Did a complete top end job on my SF over the past couple of months and have been tidying up the cosmetics on the bike at the same time. I fitted the new carbs yesterday and started the bike up for the first time in ages. It ran really well, very encouraged so far.

But... there was oil pouring from the camchain tensioner housing. I tightened up the bolts that attach it to the block and that didn't help. I figured that I had just fitted the tensioner with bolts that were just a bit too long and that they were bottoming out. I left it alone last night and when I took off the casting this morning, the thing fell neatly into two parts..

So...On a new head rebuild, despite going through the recommended procedure for tightening the camchain, what would cause enough pressure to crack the tensioner? I did torque it down evenly with a new gasket, but perhaps the wrong amount? Is there anything on a new rebuild that might cause a sudden increase in chain tension that would break the housing?

But, more simply, it probably just ....broke, failed, whatever..

SO now I need a new one. Are they the same across the years for all the XS models?
There are a couple on eBay right now but are pushing $50 including shipping , so if anyone has one lying around in this shrinking economy for sale for somewhat less than this, please PM me..

Thanks.

Gareth.

[cokeman]

I have one I just removed from an 81H. Should fit and it doosn't look like it leaks. $25 shipped. Send me a PM with your address.

Darrell

[SanDiegoMike]

It's also really easy to make your own gasket as well...if you have one, use a paper hole punch to make the bolt holes. Also, take the time to make sure that the plug that sits in the end of the plunger bore is secure as well. They can pop out. DAHIK. A litle RTV around the edge with enough time to cure before you start it up again should keep it where it belongs.

[Jerry]

Part should be the same across all years of XS 11 and the XJ 11. Little known tip that has been passed along: there is an O-ring under the jam nut. (Its actually under a small washer under the jam nut.) If it gets old / dry/ cut the tensioner will leak around this ring. Other place, as mentioned in previous threads, is around the plug that goes into the outer end of the tensioner. Use RTV or some other sealer arund this plug to completely seal it.

Have never heard of ever-tensioning causing a failure of this piece.

However, when you replace the tensioner, remove the valve cover and pick-up cover and make sure the cam arrows are ligned up correctly with the marks, or you will bend valves.

[prometheus578]

The only thing I can think of that would break a tensioner...
would be to install the tensioner with the tension rod already extended and locked in place.
Rod hits chain, tensioner body not fully seated against the head, tightening the tensioner body snaps one of the mounting flanges.

[gareth]

Prom...

I think you hit it right on.. don't remember loosening the tensioner before I installed it tighly. I did loosen it and then retighten according to regular procedure once I had it installed.

Live and learn..

Hope I didn't screw something up in there with the excess pressure. I suppose if something hadda give it might as well be an external easily replaced part..

G.

[prometheus578]

"Ya probably didn't hurt anything..."

... 'cept your pride.

It's been done many times before.

The broken tensioner thing, I mean... I have no idea what other foolish things you may have done that have hurt your pride.
(But, as confession is good for the soul... I think you should tell us)

[gareth]

My pride...?

Split in half, broke, failed...whatever...

It's the metaphoric cam-chain Tensioner of Life.

If it ain't already broken, just attempt to adjust it...

[TopCatGr58]

Hey Gareth,

Hopefully you got lucky, and like Prom said, just broke the mounting flange of the tensioner body, BUT the tensioner plunger stayed in place enough to maintain proper tension to keep the chain from hopping/skipping a sprocket tooth!!

DO NOT rotate the engine until you get the new tensioner. Also, would recommend you put the old one back on to help keep the chain guide/tension tight, to prevent slack dropping the chain around the crank sprocket.

Hopefully you rotated the engine and put it at "C" before you removed the tensioner?

When you go to put the new one on, you'll want to do it twice. First, don't bother with a gasket or sealer. Just put it on, release the lock bolt, allow the plunger to set, tighten bolt, lock nut, and then rotate engine several times CW, stopping at "C", then remove tensioner complete, loosen locknut/bolt, compress the plunger fully, set lock bolt to hold plunger in place, THEN apply gasket/sealant and replace on engine, torque bolts, and THEN release tensioner bolt, CLICK, retighten bolt, set lock nut, and you should be good to go!
T.C.

[gareth]

Nope...didn't do that. I was convinced that the bolts were just bottoming out. I had replaced all the other engine cover bolts with fancy polished stainless steel ones and I figured that I had just messed up with the lengths of the ones that I used to attach the tensioner. So this morning I decided to replace them one by one. None of that fancy thinking before I act stuff.. When I pulled the first bolt, half the casting fell off with it. So I naturally pulled the other bolt just because that's the kind of things people-like-me do when confronted with half a casting. At these moments, I typically say things like "What in the name of ( insert favorite profanity/deity/ combination thereof...) etc..
I do know enough not to whiz the starter motor at this point.. so tomorrow I will take your advice and gingerly reinstall the broken tensioner, making soothing, coo-ing noises all the time..hoping that things are not way worse than they seem.

There... There....

That always works.

[skids]

I would adjust the new one to be the same length as the old one, and push it into place to make sure it will go flush with the engine, then bolt it on. Proper adjustment using the C mark should follow, but pull the spark plugs and if you feel any resistance at all, stop. There would be the usual valve spring resistance only, nothing "rigid."

[gareth]

Good advice/
Cokeman is sending me the tensioner from his '81 and that should get me back to revving engine without the oil gush.. It had been a messy evening. I also had forgotton to tighten the upper oil lines to the cooler, but that was an easy one. Seems to be plenty of oil pressure, at least.
I guess its not the first time any mechanic, amateur or professional, ever said " its running really well, just gushing oil from someplace..."