400ex engine noise

[CranMan]

My 99 EX has started making a noise. It started doing it when it was first started and cold. It's only noticeable at a real low rpm, and only for a few seconds before it cuts off when it's cold. If I raise the rpms it goes away immediately. It sounds like some BB's start rattling around in the engine cases. I know wht loose valves sound like, its not that. It still runs fine, and I dont hear anything while riding. I'm hoping someone else has had a similar problem/noise.....:confused:

[TRFOXX]

I dont know what it is either but mine dose it to when its cold and then gose away when it warm up. She runs like a beast when shes warm but when cold and just started i do here like BB's / pings in there or something.

[Stunz]

Check the two bolts that hold the exhaust shield on.

I think it's a 12mm socket.

[doctor_915]

I was experiencing the same sound noise during cold winter riding. Them I was jumping over a creek bed cased it and got water all over the motor. The engine went put put boom. I thought something was seriously wrong but as it turned out my spark plug wasnt screwed in tight and the sound was coming from the spark not making good contact. You might have a totally different problem though but after I tightened my plug back up it runs fine.

check for loose bolts, mine did that, when i checked around, it turned out to be loose fender bolts. i nylon tied em, no more rattlin now

[TRFOXX]

Well I found the problem, it was the spark plug not tighten down all the way. I went to change out my spark plug and and it was loose. Put the new one in and cranked her down snug and no more BB's/ pinging sound. thanks for the advise Doctor 915. They should make a better tool to get down in there and snug it up better than the stock tool, but i havent found one yet though.

[doctor_915]

TRFOXX- There is a better tool to use to change the plug on it. It is a thin walled spark plug socket but I forget if it is 14mm or 17mm. Call your local shop and ask them what they use, usually they will tell you, and I am glad you got your problem fixed.