I have a 2007 400ex. It has had a top end by the previous owner. But there is a problem, and I just noticed it today. I hear a ticking noise. It sounds like it is coming from the bottom end, possibly piston connecting rod bearing. Sounds like could be timing chain also. I am taking it to a friend so he can inspect and adjust the valves. What do you guys think it is? Again I am almost positive it is bottom end. Thanks

 

I can upload a video of it running in youtube and provide a link if it will help.

 

Post a video. I had the same problem 2 days ago and found out that you have to adjust the valves when the decompression valve is engaged or you're going to have to m much slop in the right side exhaust valve which causes ticking.

 

I will post a in a few ours

 

Here is the video. I hope it helps. If it is a valve adjustment, it will happen soon. I am getting feeler gauges in the mail. And how urgent is it to fix it? Can I ride this weekend and it will still be fine?

 

Yea, it's your valve.. Mine sounded the exact same. When you adjust your valves make sure that you have it where the decompression valve on the right exhaust valve is engaged. Then adjust it to .005 your intake is .004. That will get rid of that tick

 

Alright thanks. But I don't have the feeler gauge right now. Can I go ride tomorrow and adjust the valve in the next week? Or will it damage something? I have owned the bike about a month and it started ticking a week ago, have not ridden since, and want to tomorrow.

 

With it being a decompression issue, you should be ok. The decompression only comes into play when you are starting the bike to make it an easier start. If it were mine I wouldn't ride it until I got it fixed. You can pick a feeler gauge up at o 'riellys fairly cheap.

 

Is the decompression for hot starts or cold starts? it is extremely hard to start when it is cold, and it will not idol either while cold. But once it warms up and runs for about 5-10 mins, It will idol just fine and start right back up.

 

I am STILL waiting for my feeler gauges, she has been sitting for 2 weeks bc they have not gotten here.