My brother recently had his camchain replaced by a garage on his 02 GS500.

The engine is now making a terrible noise, please can you watch the attached video and advise if this sounds like the engine hasn't been timed properly?

https://drive.google.com/open?id=1-yguSYwtP5nrC9WdJj11O2swtlMfROqq

He's taking it back tomorrow.  If this is due to poor timing, could there be engine damage?

Thank you

I'm no expert, but it does sound like the cam chain is either loose, or off by one tooth.
If they find that the timing was off, have them test compression to make sure no valves were bent.

Has he ridden the bike? Does it have normal power?

He hasn't ridden the bike yet, he's only just started it to hear this noise.

He's currently turning it into a bit of a cafe racer, so the bike isn't really ready to run properly.

If the chain is off by one tooth, and that noise is valves tapping the pistons, then we must be looking at engine damage surely? 

The bikes done 40-50k so the engine will likely be scrapped if there's damage unfortunately.

I've suggested he checks the timing himself, but he thinks the garage is trustworthy so he will let them test it

Yeah, just take it to the garage that did the work and let them sort it out.
I was thinking the noise was the cam chain slapping somewhere in the engine, not the valves hitting the piston.
I set the timing wrong once and bent the exhaust valves. The fix is to simply replace the valves. I didn't want to do that, so I just replaced the entire top end with a known good one. A decent shop should have no problem replacing the valves. While they are there it would be a good idea to replace the valve seals since its a high mileage engine.

Why was the cam chain needing to be replaced ? I've never seen these cam chains go, except ofcourse when a lot of other crap was gone, like a bad rod bearing.
Cool.
Buddha.

It's quite a high mileage engine and the cam chain was stretched to its limit per the Haynes manual, hopefully not a waste of time to replace it then?

So the garage has got back and said it's the camshaft bearings, it's uneconomical to repair, and a new engine will be required...

Now I don't know a huge amount about replacing camshafts, but I would have thought it would be as simple as removing the chain, removing the cam caps and out the camshafts come.

Chuck some new/used camshafts in, time it up and your done?  Although I believe the camshafts are machined to fit properly aren't they? Can any machine shop do this?

I'd rather not get rid of the engine if possible, as repairing it doesn't seem all too expensive.

Scratch that, he said crankshaft bearings which makes a lot more sense.

Too big a job to do at home in a garage with normal tools? Scrap the bike or no?

Ill call this bulshit.

Did they diagnose the camchain problem previously? Did they not start the bike once the camchain was replaced to check everything was good.

Their invoice should show the mileage and if it has not been ridden at all they must make it right.

Take out plugs and look inside cylinder with torch, if marks on piston,  they screwed up the timing......

I cant listen to your video but crankshaft bearings and big ends knock and rumble, not what folks previously indicated they heard....

Get a second opinion from another shop.

Thank you for the input, I have spoken with my brother who owns the bike and we are going to take it to another garage who can inspect it.  The noise sounds like it's coming from the top end so I don't understand how that would relate to crankshaft bearings. 

If anyone gets a chance to listen to the video could they advise if it does or doesn't sound like crankshaft noise?

We will also pull the valve cover off later and check timing ourselves.  Although the garage has already had the bike back so could possibly have set it properly this time, but hopefully they are not that dodgy.  Thanks for the tip on checking the pistons we will do that too.

I don't know if they started it or not after replacing the cam chain, but you're right that it doesn't add up.  Why would they replace a timing chain and then not start the engine to verify it was working? And if they did start the engine, why would they not mention the horrible engine noise? 

Admittedly the bike is not in great condition right now as my brother is trying to cafe-racer it up a bit, but these things should be standard for a garage surely?

Yeah, this engine is as simple as they come. If a garage is capable of doing any in-engine work, they should be able to work on a GS500.

I can't imagine pulling the top end apart to replace the cam chain and then not starting the bike to make sure everything is running well. This just seems weird. If it wasn't making the noise before the repair what are the odds that the crankshaft bearings went the moment after they finished?

At a minimum, they mis-diagnosed the problem the first time and charged you for unnecessary engine work on an already dead engine.

What was the original reason that the bike was in the shop getting the cam chain measured in the first place?  I agree with the Buddha; that is not a normal wear item for the GS500. 50k miles means you probably need rings and valve seals to be in tip-top shape, but that is mid-life for a well cared for GS. There is more to this story.

The sound we are talking about is a mid-pitch clack that is randomly occurring every 2 - 5 seconds. I've never heard a bad crankshaft bearing on a GS500 but it seems like it would be directly tied to engine rpm. Ask the shop how they determined that was the problem without dismantling the engine. If you dropped the sump you would probably also start to find metal bits if the crankshaft bearing was the problem.

I still think its related to the cam chain. Its hard to tell in a video, but it sounds like a chain quickly being slapped over a piece of metal. Either off by a tooth or the cam chain tensioner was improperly installed or is broken. Take the valve cover off and rotate the engine by hand using the bolt under the right hand cover or by turning the rear wheel. The cam chain tension should be consistent as you rotate the engine. After that, check the timing like you said. Other than something with the cam chain, the only other system I can think of that would intermittently make noises like that would be the starter clutch (loose bolts) but that would sound like it was coming from the bottom end.

Thanks Bluesmudge,

The bike initially went to the garage as it would die on throttle but run on choke.  We spent ages cleaning the carbs but it turned out just to be water in the fuel.

My brother and I were the ones that measured the camchain, which was apparently stretched to its limit per the Haynes manual.  He wants to keep the engine so got the work done as preventative maintenance, although it appears this may have been unnecessary based on a few replies to my posts.

The bike did have a slight clunk at very low rpm (i.e. when it was bogging down and just about to die) before he took it in, this noise is completely different though, as you say a mid-pitched clack, and not consistent like the first noise.

He's bringing the bike over to my house this evening and we are going to pull it apart and manually check everything you've suggested.  If still unsure we will then take it to a local garage for a second opinion.

Queck question, did you folks take out the cam chain to measure it? why then did you ask the garage to replace it, seeing as it was all apart?

No, the Haynes manual gives a 21 link max length figure, you can measure this between the two camshaft gears just about. 

Anyway the noise has mysteriously disappeared so we can't even take it to a garage for a second opinion as they would have nothing to listen to.  Not sure if that's a good or bad thing.

My guess is that the cam chain tensioner (CCT) was stuck after installation. It must have come unstuck and finally extended the shaft and put tension on the cam chain. You are lucky it didn't come off the cam sprockets while it was still loose and cause major damage.

You may want to replace the CCT as a precaution. I went to a manual CCT myself because I don't trust Suzuki's rinky-dink watch spring design. You can use a manual CCT designed for a first-gen Hayabusa.

Quote from: Bluesmudge on July 26, 2019, 09:11:12 AM
My guess is that the cam chain tensioner (CCT) was stuck after installation. It must have come unstuck and finally extended the shaft and put tension on the cam chain. You are lucky it didn't come off the cam sprockets while it was still loose and cause major damage.

You may want to replace the CCT as a precaution. I went to a manual CCT myself because I don't trust Suzuki's rinky-dink watch spring design. You can use a manual CCT designed for a first-gen Hayabusa.

I was going to suggest this is as well. The sounds was happening randomly every few seconds. I thought it sounded like the chain slapping against the engine. That's not a bad bearing sound.