Weird engine noise (cam chain?)

BrianW · Posted: Sat Feb 06, 2010 11:00 pm Post subject: Weird engine noise (cam chain?)

My gy-5 has been making a strange noise lately. its kind of a rattle and its off and on frequently (it seems like the way the bike is tilted affects it i.e. it will happen when on the kickstand and not happen as often while straight up and down)

I think it may be the cam chain? is there any plausible way to adjust these and if not is this something i should be strongly concerned about? Thanks!

FastDoc · Posted: Sat Feb 06, 2010 11:17 pm Post subject:

Stupid question here. Does a Lifan OHV even have a cam chain? Common sources of noise would be the engine mounting bolts, valve adjustment, or perhaps something vibrating against something else.
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Weldangrind · Posted: Sat Feb 06, 2010 11:26 pm Post subject:

Not sure on the OHC question.

How many miles on the engine? Regular oil changes? Any schrapnel in the oil?
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katoranger · Posted: Sun Feb 07, 2010 12:58 am Post subject:

Most of the GY5 models had the overhead cam engine. A timing chain would be in there. It is possibly that your chain has stretched and/or the self adjuster is not working allowing some chain slap.

TeamCheap · Posted: Sun Feb 07, 2010 3:47 pm Post subject:

Our 06 GY-5's came with a pushrod (PR-OHV) setup and I put a chain driven OHC engine in mine.

The pushrod engine has the one huge valve cover on top and the OHC engine has two small round covers front and rear for the valve access.

If it has a cam chain there should be an adjustment for it.

Our bikes made all kinds of noises until we got the engines bolted down tight.I hate running down strange noises it can take some time to find them.

Here is a link with pics.
Question about pushrod engines

TheRealWorld · Cooler than Chuck Norris Joined: Jun 29, 2008 Posts: 698

If the chain is slapping, it should have serious running issues. The chain gives you the valve timing and if it is loose enough to make a slapping noise it will run poorly. So how is it running?

knothead · Posted: Mon Feb 08, 2010 7:53 pm Post subject:

I'm pretty sure the OHV engine has a gear driven cam, the oil pump is chain driven though.

I went through something really close to what you're describing. I took my GY out for a spin after it had been sitting for a while. Came home and left it running while on the stand, it started making a really odd, mechanical squeaking/scraping sound that got worse when I reved the engine, but almost went away off the stand.

I tore into the engine, but found NOTHING. Buttoned things back up, the squeaky scratchy was still there, just like before....

Turned out to be the rubber grommet in the headlight fairing had dried up and was letting the fairing vibrate. I tightened the screws and the noise went away...

Bottom line; don't panic. It could be anything but most likely it's something simple.

katoranger · Posted: Mon Feb 08, 2010 7:56 pm Post subject:

TheRealWorld · Cooler than Chuck Norris Joined: Jun 29, 2008 Posts: 698

I am always amazed at the funny noises we can get from vibration. And one of the problems is that you can't find those vibrations in many cases.

BrianW · Posted: Wed Feb 10, 2010 12:40 am Post subject:

In my defense: the only stupid question is the one unasked, right?

I've got 5280km on the bike and I change the oil at least every 3-500 miles depending on what kind of riding I have done. The bike runs fine and feels solid as hell and there has never been any kind of shavings or anything in the oil, even during break in. I'll check for loose mounts and anything else before I panic too much. I've probably got 3 or so more months of cold here in wv anyway. Sad

TheRealWorld · Cooler than Chuck Norris Joined: Jun 29, 2008 Posts: 698

We have intelligent Ground hogs up here in Wisconsin, and Spring is just around the corner!

Weldangrind · Posted: Wed Feb 10, 2010 1:12 am Post subject:

BrianW, the reason I asked about the schrapnel in the oil was because of my experience with a 1980 XR200 (OHC). If you remove the right side engine cover, you'll spot the oil pump cover to the right of the clutch. It has three phillips head screws that retain the cover, and the cover should be removed periodically.

The one I'm rebuilding was so full of crap that it looked like it was stuffed with anti-seize. It turned out that the cam sprocket was bent, which allowed the chain to rub on the case. It was gross.

I'm not saying that there is damage in your engine. What I am saying is that the oil pump should be cleaned occasionally in any Honda vertical single (or clone). Who knows if your oil pump is starving when it is on the side stand, maybe because of crap in the pump.
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"It's better than being hit on the bum of the mind." - Hank Yarbo
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TurboT · Posted: Thu Feb 11, 2010 3:23 am Post subject:

Forgive my ignorance on motorcylce engines, but to me it seems unlikely for the noise to be internal if it's only rattling occasionally. If a chain is loose, its going to rattle whether the bike is leaned over or not, wouldn't you think?

I'd be more looking at some form of loose bolt or mount somewhere as others have mentioned.

TheRealWorld · Cooler than Chuck Norris Joined: Jun 29, 2008 Posts: 698

It appears they found the problem in the area you mentioned, just look back about 5 post. Good call!

Weldangrind · Posted: Thu Feb 11, 2010 4:14 am Post subject: