engine noise

[Ionatan]

ok...I just changed the oil in the engine and used motul instead of castrol and I feel my engine sounds a little different, also when I rev it up and then let the acceleration down(even when not moving) when the rev's go down it kinda makes a deep rattling noise or something like that, like something it's vibrating inside. bike has 70K and it's from '92, I did 7k on it and never opened up the engine(honestly I am afraid to) and I don't know about the previous owner. do you think it could  be something with valve adjustment or because of different oil? with this one it's more "rattly".

thanks in advance!

[Big Rich]

Try to hear if the rattle is coming from the top or bottom of the motor. If it's the top, it's most likely an annoying cam end rattle (search for more details). If it's from the bottom end.......I have bad news for you.......

[Dr.McNinja]

Which Motul oil? 5100? 300V? Was the castrol fully synthetic? 5100 is a synthetic blend and 300V is fully synthetic. If you did everything properly when you changed the oil you definitely didn't hurt the bike. There's a chance that the synthetic portion of the 5100 (or the entirety of the 300V) cleaned a seal or gasket that was rotted from the age of your engine which could very easily cause a rattle. Fully synthetic oils tend to be more "noisy" - but not that noisy.

Like Big Rich said, check first to make sure the noise is coming from the top or bottom first. Camchain tensioner rattle is fairly normal on GS500s from what I've read and pretty easy to fix if you have a Hayne's manual and some patience.

[Ionatan]

hi, thanks for the info, I used motul 5100 and before that castrol full synthetic, so I have no idea what it could be, i think the noise comes from the top of the engine, but I don't think it's the cam chain, it sounds like a rock in a plastic can, and I can ONLY hear it at 2000-3000 rpm.

[Dr.McNinja]

Grab some spare fuel line (it's like $2/ft. here) and use it like a stethoscope to try and listen to the engine. Bonus if you have a mechanic's stethoscope lying around. This will help you confirm it's location. It's very important you find it quickly because it sounds like a knock. If it's in the lower end it's definitely a knock and you need to have it looked at immediately. If it's coming from the top end near the camchain it's most likely camchain tensioner play, which isn't life threatening but should be addressed. I've heard some really loud camchain tensioners before and the noise only gets more annoying the longer you leave it alone.

[twinrat]

hose is a good trick  excelant.Another one for finding noises in engine is to use a long screwdriver  and put the pointed end on moter where you think noise is and ear to the handle firmly its amazing how you can quickly find odd sounds . love all these good tips it helps to spread our knowledge base ..





its not about saving a buck ,its about making sure its done right

[Oracle]

Toilet plunger handle works great too. Just uh... Wash ur hands and ear after. Seriously though. It works.