light ticking noise in a 99 yz400
Posted June 20, 2006 - 12:48 PM
Here's what I know:
1) The valves are in spec, I did them myself.
2) The cam chain and tensioner are stock, I haven't replaced them yet. I'm going to soon.
3) The motor is all stock, never been taken apart. It doesn't have a ton of miles on it, I'd guess I probably put on less than 20 hours a year.
4) I have a skid plate, but I don't think it's the skid plate amplifying the noise.
5) The noise is present at idle, in gear, going or stopped.
6) I thought it was an exhaust leak, but sealing the header and junction to the muffler didn't help.
Anybody have the same light ticking noise and actually solved the problem?
Posted June 20, 2006 - 01:20 PM
Full speed noises (once per rev) could be something like a cracked water pump gear, a loose drive gear, etc.
Posted June 20, 2006 - 03:20 PM
You've got me thinking that maybe I've got one of the valves looser than it should be. I adjusted them to be at the looser end of the spec. I know you are going to ask me if it ticked before I adjusted the valves, but I don't remember. It's been a while since I adjusted them and I don't recall. All I know is it ticked after I adjusted them, and it may or may not have ticked before the adjustment.
If it's with the decompression lever, shouldn't I feel the pulse in the lever while the bike is running?
Thanks for your input!
Posted June 20, 2006 - 04:51 PM
Here's a couple things to consider:
Is it most pronounced at idle, disappearing at speed, and louder in the air box? Could be a slide ticking in the carb (more or less normal)
Is it load sensitive, making more noise under light acceleration than decel? Could be piston slap.
Does a load make it go away, and taking the load off at speed make it "double up" (change from half speed to full or even double speed)? could be a rod bearing or a piston pin.
But before you get off on a hunt, go back and check the valves again, just for fun.
Posted June 28, 2006 - 03:02 PM
it seems to come from the valve area, but i checked the valves (several times) and they are all ok (i had just put in new valves, shims, etc).
the sound is not from the water pump area, and also not from the clutch area, it's above that..what else could be wrong in the top end?
Posted June 28, 2006 - 09:46 PM
Posted June 29, 2006 - 08:33 AM
1) cam tensioner and timing chain, it's all original
2) valve with too much clearance
3) exhaust leak
Either way, I'll do a post rebuild writ up to let you guys know if I found the problem. I think it's a good idea to let people know what you find or didn't find for future reference for people doing searches.
Posted June 29, 2006 - 09:18 AM
Posted June 29, 2006 - 12:58 PM
the piston seems ok, and the noise seems to come from the valves... the chain seems ok, no slack (with the tensioner on).. i'm kind of loosing hope..
my noise is pretty identifiable to the valve zone, and it goes on at idle, cold, warm, running... it seems a 1x noise, i tried that with the decomp lever method, and the noise seems to be 2x the decomp pulls..
Posted June 29, 2006 - 02:17 PM
Posted June 29, 2006 - 03:14 PM
i tried moving the cams 1 tooth to see if it would stop, maybe timing related.., but it didn't..
i'm starting to thing this is a worse problem, like the rod or the piston pin or something.. and this time i tried lowering the idle so that i could hear better if the noise was 1/2x or 1x..and it seemed 1/2 (same as decomp)...i'm confused
anyway, are your valves really up to spec? try changing the cam chain, it's not that expensive
Posted June 29, 2006 - 09:07 PM
Posted June 30, 2006 - 06:55 AM
oh and he started ranting right away, that YZFs were only for racing.. that they are torn apart after every race (lol.. yeah, it's like a 2 stroke but with 2x the strokes..)..
he talked about my bike as it were the most unreliable bike ever.. lol..
"oh yeah rod problems are common!".. lol..
Posted June 30, 2006 - 09:37 AM
Posted June 30, 2006 - 09:43 AM
i think it may be the CB key, and i'm going to try and check that tomorrow.. i'm searching the forum for a detailed howto eheh:)
it's sad to see that they don't even have the slightest idea of what the common problems are.. where did all the good mechanics go?
Posted July 09, 2006 - 07:07 AM
Posted July 09, 2006 - 04:28 PM
Posted July 10, 2006 - 01:53 AM
Posted July 10, 2006 - 08:54 AM
I'm still going to do the top end and timing chain when I get around to it. I'll post what I find.
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