Timing chain came off, need help putting it together again.

[MrGiggles]

Today I went to go for a ride normally, aired up my tires, checked gas and oil, and took off. I rode for maybe two minutes and I was in 3rd going decently fast my 220 popped and it made a whirring type noise. I tried to restart but it had no compression, but not seized. After a couple pulls with the pull starter it locked up. At this point I towed it back. It had a knock, but it was not cam related.

After removing the timing chain cover, I saw that the timing chain was resting on the nut that holds the cam sprocket on. It had just popped off, I have no idea why. I had just adjusted the tension, and it seemed fine. The reason I couldn't pull it over is because of the slack in the chain, it had jammed up in the bottom end somewhere. I spun the engine backwards and pull the chain tight it spins freely now, it was not broke. The cam also spins fine. I am completely clueless as to why it popped off. I wasn't even riding it hard.

Here are my questions. And there are many.
First off, will the piston hit the valves if they are stuck open and bend them? I don't want to take off the head if I have to, but if it has to be done I will. I am on a very strict budget, so the less money the better.

Second, how would I go about timing it back again? I've been reading up and the procedure I have seen is to set the piston at TDC, then line up the cam with the dot at the 12:00 position. Simple enough?

Finally, I am wondering if I will have to remove the flywheel and what will I need to do so?

Thanks.

[99prairie400]

There is a specification in the manual about how long a certain number of links of the timing chain are supposed to be. I'm sure what it is for your model bayou but there is a spec SOMEWHERE. If the chain has stretched it's possible it's flopping more than it's supposed to and could jump although the tensioner should remedy that problem by taking up the "acceptable" amount of slack. It's possible that a chain guide has failed and that allowed the timing chain to "walk" off the side of the cam gear.

I'd probably stick the timing chain back and check the compression. That's the best test on whether the head needs to come off. It's possible (although not probable) that the timing chain was a freak accident and won't ever happen again. The better chance is that something relatively small is damaged just enough to allow the jump and needs to be replaced otherwise it'll do it again. BUT if it has bent valves/damaged piston the head needs to come off anyway and that would allow you to inspect all of the timing chain components.

[MrGiggles]

Originally Posted by 99prairie400

There is a specification in the manual about how long a certain number of links of the timing chain are supposed to be. I'm sure what it is for your model bayou but there is a spec SOMEWHERE. If the chain has stretched it's possible it's flopping more than it's supposed to and could jump although the tensioner should remedy that problem by taking up the "acceptable" amount of slack. It's possible that a chain guide has failed and that allowed the timing chain to "walk" off the side of the cam gear.

I'd probably stick the timing chain back and check the compression. That's the best test on whether the head needs to come off. It's possible (although not probable) that the timing chain was a freak accident and won't ever happen again. The better chance is that something relatively small is damaged just enough to allow the jump and needs to be replaced otherwise it'll do it again. BUT if it has bent valves/damaged piston the head needs to come off anyway and that would allow you to inspect all of the timing chain components.

I'm sure the timing chain is the correct size. Tomorrow I will hopefully have enough time to release the tensioner and slip the chain on then tighten it back up to see how much slack it has. I did not here the piston hitting the valves right after it popped off, but it had no compression. So I think a valve was stuck half open, enough to release pressure but not far enough to hit the piston.

[MrGiggles]

Can anyone tell me if I have to replace the head gasket if I take the head off? I'd rather not replace it..

[99prairie400]

Oh well you already know the answer to that question... If you pull the head you should replace the gasket.

You would probably be fine if you reused the same gasket for a test and tune session to see if something you did inside there made a difference as far as the timing chain popping off but you risk losing some compression because the gasket is designed to squish down into the little imperfections on both sides the mating surface and once you move it from that exact spot it won't reform.

Can you tell anything from looking down the timing cover? I figured if one of the guides came ut of it's holder/ broke you'd be able to see that by peering down the length of the cylinder.

[86klf300guy]

yep ,a new head gasket.ounce you tighten it down and run it it cant be re used!

as for the valves you may have hit em with da piston and bent them.

for the chain popin you may what to look and your chain gudies especally the one that your tentioner is on.a worn guide can let the chain slack up and pop off.oh and cause a knockin noises if the shoe that is on the tentioner breaks off.

good luck mrgiggles keep us posted on the repairs -corks

[MrGiggles]

Originally Posted by 99prairie400

Oh well you already know the answer to that question... If you pull the head you should replace the gasket.

You would probably be fine if you reused the same gasket for a test and tune session to see if something you did inside there made a difference as far as the timing chain popping off but you risk losing some compression because the gasket is designed to squish down into the little imperfections on both sides the mating surface and once you move it from that exact spot it won't reform.

Can you tell anything from looking down the timing cover? I figured if one of the guides came ut of it's holder/ broke you'd be able to see that by peering down the length of the cylinder.

I figured that, just wanted to make sure. I tried to check compression today But even with the chain pulled tight the engine won't do a full revolution. Now that I think of it I think one of the chain guides could have broken off and fallen down preventing it from turning. I will look tomorrow.

Originally Posted by 86klf300guy

yep ,a new head gasket.ounce you tighten it down and run it it cant be re used!

as for the valves you may have hit em with da piston and bent them.

for the chain popin you may what to look and your chain gudies especally the one that your tentioner is on.a worn guide can let the chain slack up and pop off.oh and cause a knockin noises if the shoe that is on the tentioner breaks off.

good luck mrgiggles keep us posted on the repairs -corks

Like I said, I didn't hear the piston hit anything, and it still pulled over a few times without hitting anything before it locked up. I don't really know, I am going to investigate further.

Thanks.

[86klf300guy]

you wont hear the valve hit the piston.unless the valve came free from the valve keepers and fell into the cylinder. take and check rocker arm movement to see if there equal movement or lift.or excess rocker arm play or valve lash
this can help determin if you bent the valves if they dont lift the same hieght or the rocker is really loose. and a compression test would be a good thing to do also to make sure

-corey-

[MrGiggles]

She's running again!

There was a bound up link in the chain. Fixed that and it stopped hitting and turned all the way. We also fixed the tensioner because it was stuck and not tightening anything. Probably why it fell off. Compression is the same as before, and it runs decent so I don't think the valves bent.

[86klf300guy]