Oh boy, where is that sound coming from?

[Green95Hoe]

Dammit, not good. I hope you guys can give me some direction so I know where to go where I tear it apart again..

I have a newly developed pinging coming from the engine. At first sound I thought pre-det but then I remembered I havent changed anything in 4 months and I run race gas. No odd sounds at idle or low throttle. Typical cam ping from the Hotcam at idle but thats normal. The sound only exists at WOT at High RPM. Almost like a rappin Clink sound that is consistent with the engine speed. Has plenty of pull on the straightaway but on the hillclimbs its a pinch sluggish at the high RPM. I tried to record the sound but you cant hear it.

Engine Specs:
426, resleeve, 11:1, Stage 2, 450R carb, jetting has been perfect for maybe 6 months. I run a 50/50 mix of VP 112 and 93 octane at all times. Rebuild is only 9 months old. I ride it moderatly but dont race it.

Last warm day we went out she seemed to be running a little warm. Didnt really notice it till I saw how long it took to cool the block down when I got back. Oil was changed maybe 10 hours ago. I always use Rotella T synthetic. Oil level is fine and looks great. Valves are within spec. Plug looked decent so I cleaned it. Took it for a couple WOT runs in the field and took the plug out for inspection. A little orange at the top of the ceramic but thats it..anyone give me some direction.. I build the engine myself and im no stranger to engine work but this has me baffled.

Pic of the plug afterwards:
http://img266.imageshack.us/img266/742/1002110ck1.jpg

Brief Sound Clip:
Click here to watch quad-ping-clip (http://media.putfile.com/quad-ping-clip)

[MUDDIN400EX]

Man, I don't know but I do know, mine is making the same noise. Runs great seems fine at idle and low rpms but as soon as I rev up sitting or riding, some awful noise happens. I have had three mechanics listen to mine and one said cam chain tensioner but I don't think thats it at all, mine honestly doesn't sound like it's coming from engine. It is almost like a vibration. Another mech. told me it was either the upper motor mount loose or the exhaust was loose, I stripped the bike and tightened evrything on it, I was wondering, could it be something in the oil tank b/c with a stethiscope it sounds like it is coming from in there. not sure, please help me out if you find out and I will keep you posted if anything changes with mine. by the way, one tech told me that if it was him that it sounded like it wasn'y anything major so he would ride it til something changed. Just his opinion. Thanks man. Good luck

[Green95Hoe]

Thanx for the reply, im sure ill come to a head with this eventually. I just know that one day it was showed up out of nowhere so im not ignoring it. I cant take any internal engine noise lightly. I have a stethascope and I tried to listen but its hard when your holding it and driving 30 MPH. Bottom end sounded fine but I cant get a grip on the top. The sound is definetly more dominant on the left side while sitting on it. Cant be the cam chain as its self tensioning. I even checked to see if the drive chain might be rubbing but thats all good.

[F-16Guy]

If you have a stock head pipe, try putting your heel on the heat shield when you rev it up. Mine started making a nasty noise during a WORCS race, and I didn't figure out for a while where the sound was coming from. The heat shield mounts on the pipe had cracked and it was making a bunch of noise (sounded like it was coming from the engine itself).

[Green95Hoe]

checked that already. still nice and solid unfortunately. I wish it was that easy

[GPracer2500]

Does the sound seem load dependent? If you were hauling up a long hill at WOT and the sound was constant, would backing off the throttle some cuase the sound to go away?

[Green95Hoe]

Yes, instantly goes away when I back off the throttle. Its only there under WOT and usually at higher RPM's. It doesnt seem to get louder as the RPM increases either.

[GPracer2500]

Originally posted by Green95Hoe
Yes, instantly goes away when I back off the throttle. Its only there under WOT and usually at higher RPM's. It doesnt seem to get louder as the RPM increases either.

That answer makes me think it IS detonation. Deto can sound A LOT like something is loose and vibrating on the engine.

"...rappin Clink sound..."
"...pinch sluggish at the high RPM..."
"...seemed to be running a little warm..."
"...No odd sounds at idle or low throttle..."
"...only exists at WOT..."
"...goes away when I back off the throttle..."

All those things can be explained by deto. I don't normally like trying to evaluate plugs unless I can examine it in person or have VERY up-close and clear pictures (yours is pretty decent though), and know exactly how old the plug is and what technique was used to "color" it. But, the little specs that I think I'm seeing on the insulator and around the inside of the threaded area could also be explained by deto.

It's somewhat strange that you'd get deto all of a sudden and with the use of a 50/50 fuel mix. But anything is possible. How old is the fuel? Is there a chance the fuel in the tank somehow ended up being straight pump by mistake? Also, carbon depostites from rich jetting can increase dynamic compression enough to cause deto to pop up seemingly out of nowhere. Hotter than normal riding temps or harder running then normal can influence deto as well. A sheared ignition timing key could let flywheel move enough to push the ign timing into a range that promotes deto.

Try running straight (fresh) race fuel and see if the knock goes away. If you can't get the sound to happen with full race fuel then it's a deto issue for sure.

ETA: It could be something other than deto but I'd make sure deto is eliminated as a possibility. There's just too many things that point to deto as the cause....

[GPracer2500]

I just notices your jetting specs and location. Doubt you're too rich.

At the other end of the spectrum, being too lean creates conditions that favor deto. Leaner = hotter and heat is one of the catalysts that influences the development of deto. You might try richening your main a little in an effort to bring cylinder head temps down. That could make a difference.

Some air cooled engines (I'm not specifically talking about the 400EX) can never be jetted for best power (best power coming right on the edge of too lean). They just can't handle the heat for anything but a very short period before destructive abnormal combustion starts to happen.

[GPracer2500]

One last question. Is the sound more likely to happen when the engine is real hot? If so, that's one more thing that would suggest deto as the source.

[Green95Hoe]

Wow, thanx GP, your input is appreciated more than you know. Ill run it straight 112 and see what happens. I probably should have taken a pic of the plug when I first took it out. It was new when I did the rebuild last Feb. Ill put a new one in for the straight VP so I can get a better estimate of whats goin on. There is no chance the fuel is anything less than 93 and its maybe a month old at best because I ride alot. I cant rule out carbon deposits in the engine cuz she was a little rich back when I first broke the 426 in. I didnt go to VP until maybe 2 months later when I switched to the 450R carb. If there was in fact carbon in there, would the VP clean it out? Still a fresh engine for the most part so cant be that bad. Well..... there is the break in incident last winter that makes me wonder about the crank and connecitng rod bearings....:(

http://www.exriders.com/vbb/showthread.php?s=&threadid=211678

[GPracer2500]

Hmmm. That does throw in a bit of a wild-card. I'm still thinking deto though. If straight race doesn't make it go away then there might be other problems going on....

[patches85]

Maybe the wrist pin is shot.

[ModManiac]

From the picture the plug looks a little yellow on the top does it look that way to you? If so its definately detonation and from your responce it only does this under wot, does it sound like very bad valve noise because that is what detonation sounds like? You might want to retard your timing a bit.

[Green95Hoe]

The top of the plug is more of an orange color. Probably only ran the bike maybe 10 min to make it look like that. I was talking to a friend today about what I would hear if a wrist or crank bearing went and he said a pain under load. Of course his knowledge is limited to car engines but its the same principle. Retard timing? How would I do that? Isnt that all controlled by the CDI? Ive been away this weekend so I didnt get to ride. Im just a little nervous about getting on it while this is happening. I also noticed that she pops and fires a little when im rolling down a hill off the gas and using the engine as a brake. I have a 190 Main in the 450R carb and the K&N is freshly cleaned with an outerwear and no lid.

[hondajoe05]

timing chain?

[Green95Hoe]

I will check but im pretty sure the timing chain is self adjusting.

~Brad

[F-16Guy]

I've never had a problem, but I've heard of a couple of timing chain tensioners breaking.

[Green95Hoe]

Its louder on the left side

[Green95Hoe]

Alright guys, I ran straight 112 through her today for about an hour. No difference whatsoever. I pulled the plug afterwards and its identical to the way it looked before. I took another pic. I also fired up the video camera and blipped it in my field a few times. Its much more noticeable in the video clip. Especially at the end when I nearly hold the camera between the oil tank and tire.

Here is the plug again:
http://img363.imageshack.us/img363/5193/1002113qe0.jpg

And here is the video clip:
<embed src="http://lads.myspace.com/videos/vplayer.swf" flashvars="m=1142934999&type=video&cp=1" type="application/x-shockwave-flash" width="430" height="346"></embed><br>Get this video and more at <a href="http://vids.myspace.com/index.cfm?fuseaction=vids.individual&videoid=1142934999&n=2">MySpace.com</a>

[F-16Guy]

It looks like the tip of your plug is bent!! I would probably just tear it down now before you REALLY have to go parts shopping :eek:

[Green95Hoe]

Yeah, that looks like what its comin to. This is gonna suck :mad:

Its not bent, its just the way the pic came out. I promise

[pual0101]

tougher with one hand ins't it? haha
i dont know, ive heard a few sound like that, may just need a rebuild

[brian-250]

Just a while back here, i worked on an '03 EX that was ticking for about 4 months everyone around here listened to it and said it was fine i disagreed. Well i was riding with the boy that had it one day and it just cut loose to a knock in the higher RPM's. So i brought it back and tore it down and it was a spring broke in the cam tensioner, so i would pull that off and take a look at it.;)

[Green95Hoe]

Hmm. makes a bit of sense actually. Was it the part that I can just pull out of teh head without actually takin the whole head off?

[Green95Hoe]

Well I got the engines top end stripped down tonite. Looks like there is a little play in the connecting rod to wrist pin connection. Apparently the piston was rockin back and forth and the piston skirt is scuffed up a bit. The scuff mark is only on the bottom half of the skit so it looks like the piston was twisting when it came out of the sleeve and then straightened back out when it proceeded up.

Can I get an oversize wristpin or do I have to replace the whole crank assembly. I know for car engines you can get oversize wristpins but im not sure on the quad engines and I havent seen it mentioned here yet.

http://img87.imageshack.us/img87/6995/1002163lc8.jpg
http://img132.imageshack.us/img132/502/1002164rr8.jpg

also check this out, it appears the cam chain was grazing the side of the jug. Is this normal???

http://img180.imageshack.us/img180/2426/1002165ju9.jpg
http://img169.imageshack.us/img169/9353/1002166jc3.jpg

[GPracer2500]

That sucks. At least you figured out where that noise was coming from. That might have eventually cracked the bottom of the sleeve off and then you'd really have problems.

I've not heard of anything other than standard wirspins. Maybe it's time for a stroker! (hey, gotta find the bright side, right?)

Those marks near the camchain are weird.

[Green95Hoe]

Yeah, the marks really baffle me too. I dont see how that could happen unless either the crank or the cam is moving. Obviously the crank isnt moving and the cam cant go anywhere with those holding pins in place. This concerns me at least a little cuz if I go stroker im running the HD cam chain which Is larger to my understanding. If its larger then wouldnt this become more of a problem?

[pmptrk]

As far as the "cam chain marks" I am not absolutely positive, but I think when I had mine apart, I saw similar marks but couldn't see how it would've happened so I didn't think much of it. Your pic just looks a little familiar to me. It might be possible its a machining defect or something of that sort from the factory. Mine was with a stock chain at the time.

[Green95Hoe]

Its not so much that the marks are there, but how wide they are. See the marks are the full span of the opening leading me to believe that the cam chain has been all over the place. Im no engine expert so I dont know how that tensioner is holding the chain under load but it just seems like it had to be pretty sloppy all together to do that

[wysse]

was the cam chain lose at all?? thats wild!

[Green95Hoe]

Nope, that baby was nice and snug before I pulled the tensioner out

[patches85]

Those marks on the cam chain tunnel are from where the parting lines on the castings were cleaned up with a die grinder, not the cam chain.

[pmptrk]

Originally posted by patches85
Those marks on the cam chain tunnel are from where the parting lines on the castings were cleaned up with a die grinder, not the cam chain.

Good, that makes me feel a little better about my guess that it was something from the factory. I wonder if that means that every one has these or similar marks at those locations.

[F-16Guy]

There are a couple of Wiseco Hot Rods cranks on eBay right now. They start at $87, and only one of them has a bid with 16 hours to go. You might be able to get away pretty cheap if you can pick one of those up for under $200. That would save you the labor cost to replace the rod, and you could probably swap the crank assembly out by yourself with a Clymer manual.

[Green95Hoe]

Thanx for all yoru help guys. I decided to go with the complete 460 stroker kit that Lukes Racing has for 750. I posted about it in another thread. Comes with absolutely everything except cam, studs, cam chain and clutch springs but I can get all those from him as well. I will keep everyone posted