metallic 'slapping' noise

[ossylad]

hi all... ive a problem with my 1991 3xw ABS. its really annoying me and i cant figure it out. ive put a new super heavy duty chain on, new front and rear sprockets checked everything is fastened etc and am really stumped. i feel the noise may be engine related and am really concerned it may be terminal. at low revs under acceleration and deceleration i hear a loud mettalic slapping noise, almost like a big clicking sound (if you know what i mean lol) the bike doesnt always do it and sometime it may occur a few times in quick succession. it puzzles me and is very disconcerting. the engine is smooth and powerful at higher revs (i cant hear the noise then if it does occur!) doesnt smoke and has only done 48000 miles. the bike is good, with a full yamaha service history. i would be grateful for any help or suggestions, as this is affecting my confidence in the bike. ( i dont want something to let go at speed). all suggestions and help would be gratefully received.  cheers   ian.

[novaraptor]

Did you change your front sprocket size? If the noise just started after the chain and sprocket change, I would suspect that the chain is clanking against something inside the sprocket cover.

Novaraptor

[ossylad]

hi, no the sprocket size is standard, the noise was there before the change of sprokets, it seems to come from the left side/underneath/engine... its so bloody frustrating, you cant ride with no helmet over here.... to really get your ear down low to try and identify where exactly its coming from.!!!   cheers for your help.  ian

[jscgdunn]

My son's 92 has what sounds like something similar;  I always thought  it was starter chain. No noise on deceleration though.

[movenon]

OK, if you can, run it down the road, here's the tricky part , take your left hand and try to touch the case covering your front sprocket. If you feel the clicking there then loosen up your chain. Or, just loosen up the chain and see it it diminishes or go's away. Mine will (or use to......, sad story)  would click like that if the chain was set to tight. Just a thought...
George

[FJmonkey]

+1 George, too tight or too loose. Chain slap (too loose) can be troubling to diagnose...

[ribbert]

OK, if you can, run it down the road, here's the tricky part , take your left hand and try to touch the case covering your front sprocket. If you feel the clicking there then loosen up your chain. Or, just loosen up the chain and see it it diminishes or go's away. Mine will (or use to......, sad story)  would click like that if the chain was set to tight. Just a thought...
George

George, why wouldn't you set the chain tension in the garage? As far as I know that's the only way to get it right.

Noel

[ribbert]

hi, no the sprocket size is standard, the noise was there before the change of sprokets, it seems to come from the left side/underneath/engine... its so bloody frustrating, you cant ride with no helmet over here.... to really get your ear down low to try and identify where exactly its coming from.!!!   cheers for your help.  ian

Check the exhaust pipes are tight in the head. It is not uncommon for them to loosen up and "jump" in and out and make a banging noise. Long shot but only take a minute to check.

Noel

[movenon]

OK, if you can, run it down the road, here's the tricky part , take your left hand and try to touch the case covering your front sprocket. If you feel the clicking there then loosen up your chain. Or, just loosen up the chain and see it it diminishes or go's away. Mine will (or use to......, sad story)  would click like that if the chain was set to tight. Just a thought...
George

George, why wouldn't you set the chain tension in the garage? As far as I know that's the only way to get it right.

Noel

Noel I was just lazy and wanted to get it out for a spin. As the rear end was jacked up I did set it looser than spec but it wasn't loose enough. It made a clicking noise actually most noticeable while at low speed (probably because I could hear it then)... I just loosened it up more and it went away. I think I have about 1 1/4 inch (around 31mm) slack in it now. It didn't seem to cause any damage.

You are correct I should have disconnected the shock and run the swing arm up and down through the tight spot and checked it.
George

[Goetz]

+1 on chain too tight. Just had and fixed this problem. kookaloo

[ossylad]

HI... ive just had the bike on a stand running at low revs in first and second.... when you here the noise, to be honest it is almost like high pressure exhaust gas escaping, ive checked the studs on the down pipes and all is well there.  ive no idea were to look next. the bike makes the noise when warm. also noticed that my new chain is all over the place. ive checked it out for over-tight links and everything seems fine it just appears to jump about alarmingly all over the place.... v worrying, i had the chain professionally fitted... i didnt expect to see so much movement, is this because it was on a stand? will it tighten up when the weight of the rider is on the rear suspension?  all help gratefully received.  cheers  ian

[movenon]

HI... ive just had the bike on a stand running at low revs in first and second.... when you here the noise, to be honest it is almost like high pressure exhaust gas escaping, ive checked the studs on the down pipes and all is well there.  ive no idea were to look next. the bike makes the noise when warm. also noticed that my new chain is all over the place. ive checked it out for over-tight links and everything seems fine it just appears to jump about alarmingly all over the place.... v worrying, i had the chain professionally fitted... i didnt expect to see so much movement, is this because it was on a stand? will it tighten up when the weight of the rider is on the rear suspension?  all help gratefully received.  cheers  ian

If you had it on the center stand then yes the chain will be very loose. It will be at it's tightest when the rear sprocket / swingarm pivot point and front sprocket are in alignment. Yes it will tighten up with you on it.

There are gaskets in the exhaust outlet ports. Could they be leaking ? Caution......please do not over tighten the cap screws holding the exhaust headers. If you are hearing and air leak then also take a look at your plugs... Are they snug ? TQ to spec.
George

[novaraptor]

Hi Ian, 
Just checking back to see if you cleared the problem up.  Also so that this will bump you back up in case someone else has a probable solution..

Jerry

[ossylad]

hi there, no not yet.... i'm going to drop the exhaust system and replace all the gaskets there and see if that helps.  although im not looking forward to battling with the exhaust studs!!! they look well scabby and difficult!! i  have noticed the gaskets look worn and tired when i removed the silencers. i guess all the exhaust gaskets get tired over time.  i may even invest in a complete new set of silencers!!  any ideas about which are best suited to the FJ?  cheers ian

[Bones]

My 93 makes a rattley sound when you let the clutch out to take off, or accelerating from a slow speed in a high gear, but fine after that.

I tried to track it down one day by having the bike running on the centre stand, put it in gear, foot on the back brake, and letting the clutch out slowly while putting my head down each side of the engine.

I couldn't track down where it was coming from, because head down right side I thought, Yeah the clutch, head down left side and thought Mmmm... maybe not, and in the end gave up.

I'm not too worried about it because it's always made that noise apparently. The brother owned it before me and he said it made that noise when he first got it with 30,000 kms on it. he did 57,000kms on top of that before I bought it, and I've put another 17,000km on it.

It's got 104,000 kms on it now, the noise is no worse than when I got it, and if was a sigh of mechanical meltdown, you'd think something would've happened by now.

                                                                               Tony.