Bloody h*&^^**&^@!@@@@!!!!

[clcorbin]

Just when things are coming together and the bike is starting to run right, THIS happens!!!!

On the way home from work this evening, I was about 6 blocks from the house. I had just gone around a tight turn (basically a 90 when one road ends and you turn onto the other road) and was at around 3500 rpm in second and just rolling into the throttle when the bike "hiccuped". Almost like a very light backfire, but with a slightly more "metalic" sound to it.

Yes, I know. Bad sign...

Of course, the engine was still turning over at this point, but it was most definitely dead. Plus, it wasn't making the correct "pumping" sounds while turning over. Again, bad sign...

THANKFULLY I was able to coast down hill until about one block from my house where I had to get off and push this heavy monster UP HILL the rest of the way home. Did I mention this beast is HEAVY?????

When I got home and after I finished cussing (mostly at any rate), I pulled the timing chain adjuster off and pushed finger against the chain guide.

Yup. Completely loose. The chain either completely jumped off the sprockets or it flat broke.

Please insert appropriate cuss words here.

So, other than the four exhaust valves and timing change (which I already have thanks to a great eBay deal I came across and couldn't pass up...), what all do I need to get this beast running again?

[trbig]

Do you have the head off? How do you know it's only exhaust valves? You may have not bent any (Doubtfull.. but possible) or just one.. or all of them. You won't know until you take the head off and check it. Depending on the shape of the head gasket, you may be able to re-use that, but I would at least put new valve seals in since you'll be there anyway, and you better plan on a valve cover gasket.

Tod

[Rickrod3]

Question for you

Sorry to read about your timing chain issue.
Always cringe when I read about them
I'm curious; How many miles on the bike.
Has the engine had any top end work and how long ago.

hope you do not have too many bent valves.

Rick

[petejw]

just reading what you wrote

" I pulled the timing chain adjuster off and pushed finger against the chain guide.
Yup. Completely loose."

if you pull the adj off, the chain will be loose anyway,
did you do a compression check prior to pulling the adj out,
i wouldve also removed the rocker cover and see if i could align
the dots on the cam, to tdc on the crankshaft.

also with the rocker cover off you can see if the valves are bent
by an excessive gap between the cam and the valve bucket.

[skids]

The cam chain adjuster is the WORST design flaw with the xs11.

[79XS11F]

I would not turn the engine over any more at this point without the valve cover and spark plugs removed. Reinstall the tensioner for the time being. Turning it over without knowing what the issue is might do more damage.
If you dropped a valve that did not manage to get wedged with the piston you will know right away because the bucket will be well up in its bore but that is unlikely the case. Turn it over very slowly and confirm the cam timing as suggested. If everything is still as it should be then your going to have to pull the head and inspect the valves and piston tops.
I hope it's a minor issue.
Rob

[79XS11F]

The cam chain adjuster is the WORST design flaw with the xs11.

It is in deed a poor design but most of them have been messed up one way or another by POs who did not bother to use a torque wrench on the bolt and lock nut set up.
Rob

[crazy steve]

'Metallic' sounds are never good....

Good luck

'78E original owner

[clcorbin]

The engine turned over a LOT after the "hiccup", so any damage was already done.

As for how loose the tensioner guide was, my finger is a LOT longer than the plunger on the tensioner and I still didn't hit any tension. The chain is definitely all the way off the sprockets or broken. And no, I have not pulled the head yet. It just died about 15 minutes before I posted and I had to go to a night class, so...

The bike has had some head work about 16 years ago and 25k miles ago. My brother had the bike at that time and he made the mistake of removing the adjuster to clean and inspect it. You can guess what happened. At that time, it required 4 exhaust valves and he also replaced the timing chain. At this time, it has right over 60k miles.

When I first started going through this thing last month, one thing I did do was adjust the tension as it did have some excess valve train noise. I used the book procedure and I did hear the tensioner make that little "tick" sound when the adjuster lock bolt was released, so I THINK it adjusted out the extra slack. Plus, the top end was definitely quieter afterwards! Of course, with an XS11, "quieter" is definitely a relative term, at least on my bike.

Hopefully, over the next couple of days I'll have the time to pull the head and see what is REALLY going on in there. Maybe I got lucky and didn't kill any valves... Right! Needless to say, I'll keep everyone updated on the pain.

On the "finding the silver lining" front, at least I'll have the opportunity to install the Ventura self adjuster I picked up last week from mxmike.

Now that I think about it, buying a new timing chain AND a new timing chain tension adjuster when I didn't actually need either one was a sure way to get something broke!

[clcorbin]

'Metallic' sounds are never good....

Good luck

'78E original owner

Amen brother! Amen.

[trbig]

Well.. One silver lining at least. Being a 79 model, the valves are the same as the 750 models and are much cheaper and more available than the valves for the later head.


As said, Good luck.


Tod

[clcorbin]

Thanks for the insite Tod. I did get the valve cover off today between classes. The chain is definitely broke. The strange thing is it actually looks like it is in pretty good shape. I need to pull the new one out of the package and compare side deflection to be sure, but the old chain looked better than I expected for a chain that broke.

I wasn't able to get the head off before I had to pack it up for the day. I did get all the head bolts off as well as the exhaust, but I still need to pull the carbs (always fun!) before I can yank it.

Other question: Are there any good threads about feeding that new timing chain down down and around that crank sprocket? I am REALLY not looking forward to that!

[bikerphil]

Cam chain tech tip.....

http://www.xs11.com/forum/showthread...ight=cam+chain

[trbig]

Before you go tugging on that head, make sure those two nuts are off on the front and back middle of the head... not just the 12 big head nuts.. as well as the oil line.


Tod

[clcorbin]

Before you go tugging on that head, make sure those two nuts are off on the front and back middle of the head... not just the 12 big head nuts.. as well as the oil line.


Tod

Once more, Thank You! I knew about the other two bolts, but I had completely forgotten about them. I ASSUME I would have seen them when I pulled the carbs, but...