I've got an 05 Z400, there are no major mods yet. I just put on 18 in razors on the rear and 20's on the front. I ride predominately on a mx track with the ocassional trail ride. After putting on the new tires I took it to the track and I'm now getting this raspy noise at around 3/4 trottle. I don't think it's related as it seems to be eminating from the engine. The engine has around 12 hours on it and despite the break in recs I have to say that I haven't exactly been gentle on it. I don't believe it's a jet issue as despite the raspy noise, it doesn't seem to bog down or loose power. I know the valve clearances need to be checked at around 20 hrs seat time. I've cleaned the air filter and made sure not to over oil it. I'm not the most mechanically inclined but I'm more than happy to learn so please be as specific as possible. Any help would be greatly appreciated. Thanks in advance and if your ever in my neighborhood, stop over for a cold one.

 

Bump

 

Wow, that's a tuffy. Can you replicate the sound with it in neutral, or does the bike have to be in gear and moving. Please do not repeatedly wind out a motor in neutral, it's one of the hardest things you can do to a motor, other than being hard on it before it's warmed up to operating temps. You can use a broom stick. Place one end on the motor (the end w/o the bristles [img]i/expressions/face-icon-small-wink.gif[/img]), and place your ear to the stick, you can use it to pinpoint exactly where the sound is coming from. It could be a perfectly normal sound. It could be your valves. It could be in the bottom end. It could be in the tranny. It could be a myriad of things. Could it possibly be something rattling?

Oh, and as far as break in, read this. Ride it like you intend on riding it, just don't stay at the same rpm for extended periods of time.

 

I can replicate the sound even in Neutral. It sound like a super fast constant rattle. It only happens at around 3/4 throtle with the revs in the high range. The weird thing is that the bike runs fine. It almost feels like it has more power but the noise is definately destinct and you can tell when it starts. I've cheched all the bolts and motor mounts and they are tight. The engine seems to run hot but the temp lite never seems to go on. I'll try the stick trick tomorrow. I'm planning on hitting thr track for a while. Do you think I should wait to ride until I find the problem? I read that article before and I can see the reasoning which is why I have been riding so hard. Hopefully it's the truth. Thanks for the help.

 

Well if it turns out to be a serious problem and you keep running it (especially hard like you mentioned) that will only lead to big $ in the near future or even more $ if you find it later. Either that or it could be something silly like something rattling in the bottom of your gas tank (if its metal, don’t think it is).

 

My bet would be valve adjustment. My pal's Z went without adjustment for proabably a little under 2 years. Boy, let me tell you, it made some neat noises . . . all of the time. He got the vavles adjusted finally, and voila, sounded like new. But, I would agree with snowbuster in that, if it is something else, you are gonna be sad when the engine grenades. Take it to your dealer just to be sure . . . can't be too safe with a $6000 toy.

 

Thanks for the input guys. I'm thinking it's a valve clearance issue as well because other than the noise it runs well. I took it to the track yesterday and she ran beautifully until I ran out of gas. Scared the hell out of me but that's what I get for not checking the tank.