Clicking noise

[Dave9640]

Hi my 400ex is making a clicking noise while running. It's constant on click every 4-5 seconds til you give it some gas then it changes to one click in a longer span. Could this be a valve if it is I thought it would be more like a rattling? Any advice on what to look for and hopefully how to fix? Thanx Dave javascript:smilie(':rolleyes:')

[gt400ex]

Do a valve adjustment to see if it helps. The 400s make a "clicking" sound so if its running good there probably is no problem.

[Zeb400EX]

it could be the timing chain. mine started doing it when the motor was cold,but it got worse and started doing it all the time. so i replace the timing chain with the crf 450 heavy duty chain and all the clicking went away.

[bigbad400]

i thught that too( if its running good its prolly normal.) but mine threw the crank the other day. it was just a slight tick and it sounded like the valves. came up a steep hill and was loosing power so i grabbed 2nd and tunk! rod stuck into the electric start. and there i sat. whats even worse is i had to have a suzuki pull me home. lol(its mine too, z400 with a pipe)

[alex10]

My old quad with a bad timing chain sounded like this.

http://www.youtube.com/watch?v=vfNgYwGMVh8

[jasonanderson1]

I get 1 or 2 tap when i start it cold once in awhile...could that be anything bad?? or just a factor of starting it cold?

[bigbad400]

more than likely that is caused by oil viscosity in the cold or a slight valve noise. a couple taps is fine. continuous taps clicks or anything once warmed up other than the good ole honda rattle, is no good. these machines have a loud cam noise, especially on a stg2 or 3 cam. i have built 3 now(one stock, one 426 and one 440) and blew up the stock and the 440 both. once was valves and once was crank. both noises were about the same. just a constant ticking in the right side. the 426 is a good strong runner and has no noise at all. (built that one to last!)

[wolf400]

its prolly the cam decompressor. i cut the peice off my rocker arm so it wouldnt make the tick. and it dont now. its more than likey nothing wrong its just a 400 and they make noise

[NacsMXer]

Originally posted by wolf400
its prolly the cam decompressor. i cut the peice off my rocker arm so it wouldnt make the tick. and it dont now. its more than likey nothing wrong its just a 400 and they make noise

X2 it could very well be the auto decompression mechanism on the cam if you still have the stock cam in it. They have been known to make a phantom clicking/ticking sound that can come and go as you play with the throttle.

Here is a video of MtnEX's cam decompressor making the sound. Does yours sound anything like this?
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[bigbad400]

so how do we stop the cam decompressor noise? i have the stg 2 hotcam and i still have that noise and it makes it hard to hear anything else with that annoying ticking.

[NacsMXer]

Originally posted by bigbad400
so how do we stop the cam decompressor noise? i have the stg 2 hotcam and i still have that noise and it makes it hard to hear anything else with that annoying ticking.

The Hotcam eliminates the stock cam decompressor mechanism...you don't have one anymore. It is a known fact that Hotcams make a ticking sound that is louder than stock. As long as your valves are adjusted correctly, your timing chain isn't stretched/old/worn out, and your timing chain tensioner are functioning, its always going to make that noise because of the Hotcam.

[bigbad400]

they dont have the decompressor on the cam but the mechanism in the rocker cover still makes a hell of a tick, you can aparentyly take that lobe off the rocker and the tick will stop.

i can tell the dif between the cam noise and the metal to metal tick that thing makes.

[NacsMXer]

Well then your ticking sound has to be something else.

See the way that the stock decompressor works is it is a small one way clutch with one skinny cam lobe that is pressed onto the cam itself. On the rightmost rocker in the head cover, the rocker pad has a very small extension of the pad surface built into it that the other rockers do not have. That skinny cam lobe on the decompressor mechanism rides on the small extended piece of pad on the rocker to activate it. Look at the rightmost rocker in this pic and you will see the rocker pad has a small extension built into it:
http://img691.imageshack.us/img691/9929/pic3jp.jpg (http://img691.imageshack.us/i/pic3jp.jpg/)


The fact of the matter is if you don't have a decompressor mechanism anymore, that extension of the rocker pad isn't contacting anything. The skinny cam lobe the rocker pad extension used to ride on is now gone.

So something else is the culprit here. Could you post a video of the noise? That would make a huge difference for people to decipher the sound since different noises can indicate different things.