knocking

[strongarm29]

I am hearing a small knocking noise in my top end when the bike gets hot. I can run it for about 25 to 30 mins before this actually starts and I was wondering what all it could be.

[mcgrath]

Is it a "knock" or a "Tick" because all 400ex tick like a bugger. You may need to adjust your valves if you havent lately.That might make it a little quiet down a bit. Check your timing chain tensioner also.

[strongarm29]

I think it is more of a ticking sound, I have all the plastics and head off now so I will check the valves and tensioner as well. Thanks

[mcgrath]

right on, mine ticks when it gets hot too but always runs strong and runs well. I could probably use a new chain and tensioner but thats for another upgrade.

[dankbud42o]

yea i noticed mine ticking today when it got hot..whats the caused by? and how do i fix it? is it fixable or its supposed to tick?

[GPracer2500]

Originally posted by strongarm29
I am hearing a small knocking noise in my top end when the bike gets hot. I can run it for about 25 to 30 mins before this actually starts and I was wondering what all it could be.

Other than the engine being hot, under what circumstances do you hear it? Does it occur when idling or only under a load or?? Does it seem perfectly in time with rpms or is it somewhat erratic?

Any mods?

[dankbud42o]

i dont THINK mine was doing it on idle, mostly the high rpm is where i noticed it....

[danzigg]

I just noticed mine make's a ping noise under heavy load in 5 gear with the throttle wide open when it gets run real hard.
I noticed it doing it at the waynoka sand dune july 4th .
Dont hear it when we trail ride cuz i dont thing it get's hot enough?

i put a .20 over piston in it in dec-08 .

[GPracer2500]

Originally posted by danzigg
I just noticed mine make's a ping noise under heavy load in 5 gear with the throttle wide open when it gets run real hard.
I noticed it doing it at the waynoka sand dune july 4th .
Dont hear it when we trail ride cuz i dont thing it get's hot enough?

i put a .20 over piston in it in dec-08 .

That is the abnormal combustion phenomenon known as detonation (otherwise known as: engine knock, spark knock, knocking, pinging).

[strongarm29]

I hear it at idle as well but just barely. It is mostly when im giving it throttle. I dont have any major mods just full white bros exhaust and dyno jetted carb.

[GPracer2500]

Originally posted by strongarm29
I hear it at idle as well but just barely. It is mostly when im giving it throttle. I dont have any major mods just full white bros exhaust and dyno jetted carb.

Whatever you're hearing is probably something different. Detonation isn't likely to occur when idling.

[mcgrath]

Originally posted by danzigg
I just noticed mine make's a ping noise under heavy load in 5 gear with the throttle wide open when it gets run real hard.
I noticed it doing it at the waynoka sand dune july 4th .
Dont hear it when we trail ride cuz i dont thing it get's hot enough?

i put a .20 over piston in it in dec-08 .

If you hear a ping noise you need to rejet. .20 piston. pinging is caused by lean fuel air mixture, wide open is your main jet, Id try going up a size or two. There has been alot of good threads done on jetting.

[danzigg]

Im running 170 and 55 with a fmf power core 4 should i up the main?
thanks for the help.