Timing Chain Let Go

[Guest]

I am in the process of rebuilding my 1981 gs450l. its been running good the past 2 years. I came up on a stop sign and while sitting there idling the engine made a small bang. It shut off instantly. I walked the block home grabbed my truck and hauled it home. I tried turning the engine by hand and no luck. I removed the valve cover and found my timing chain broke. It feels like its lodged in the bottom of the engine causing it to lock up. If I can successfully remove the chain, can I just replace it or should I open up the engine and see what else is going on? I know the timing chain tensioner has been leaking, but I checked the oil level and its full. I love my little twin and money isn't there to do a rebuild on the engine, as of right now. If I end up having to tear into the engine this bike is going to be parked for a while, until funds get there for a rebuild or a used engine.

[tkent02]

I am in the process of rebuilding my 1981 gs450l. its been running good the past 2 years. I came up on a stop sign and while sitting there idling the engine made a small bang. It shut off instantly. I walked the block home grabbed my truck and hauled it home. I tried turning the engine by hand and no luck. I removed the valve cover and found my timing chain broke. It feels like its lodged in the bottom of the engine causing it to lock up. If I can successfully remove the chain, can I just replace it or should I open up the engine and see what else is going on? I know the timing chain tensioner has been leaking, but I checked the oil level and its full. I love my little twin and money isn't there to do a rebuild on the engine, as of right now. If I end up having to tear into the engine this bike is going to be parked for a while, until funds get there for a rebuild or a used engine.

Don't know about your engine but buying a used engine or even a parts bike with a running engine would be far cheaper than rebuilding.

[78gs750e]

If it were mine I would tear it apart far enough to check over for damage. Make sure the valves and pistons didn't hit, and that the chain wraping up didn't damage something below if all is well your out some gaskets and time. If its bad you can always look for another motor.

[81gs450l]

I guess i may toy with the idea of a used engine. Maybe i will look at doing a 500 swap. This is why i keep telling the wife we need to go visit my dad. He has another gs sitting and waiting for me.

[eil]

New engine is probably the best bet. At a minimum, you probably have a bent valve or two. I don't know for sure if it's possible to replace the timing chain without a rebuild, but I'd guess not.

The good news is, parting out the good bits of the engine might net you enough cash to pay for a new engine.

[pete]

I'd be ripping the head and cylinders off and checking the sprocket on the crankshaft out.

Could be as simple as jamming on a chain guide, but you need to see for yourself...

[SqDancerLynn1]

You have No choice but to take it apart which would have to be done to replace the chain and maybe the chain guides

[Mekanix]

That sucks.

Best thing to do is replace the engine.
Second best is to tear it all apart, inspect everything and replace whats needed while doing some preventative replacing as well.



The hack way to do it is to take the valve cover off and fish for the chain and pull it out. If the engine is locked up you could turn the tire backwards in sixth gear and break it loose.
After that look for any missing parts to the chain or any damage like valve buckets that are half way down or valve guides that are torn.

You can replace the chain without rebuilding but your taking chances with reliability and you won't be installing a proper endless chain.

The yamaha xs 400 I think, has the same 219 chain and the length was pretty close to the 120 links needed and that chain had a master link as well.

You could use that and get away with it for 50$ for the chain.

But your running the risk of a failure of the master link. Potentially at speed