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valve train knocking

22486 Views 15 Replies 8 Participants Last post by  trextr
I have a very loud knocking from im assuming the valve train. When at idle it rattles fairly loud. Rev it up and it gets a bit quieter (possible low oil pressure?) While driving at a steady load it mostly goes away to the normal valve noise. If I lug the engine or accelerate then it get really loud. thought it was engine pinging at first but fuel grade never changed anything. rechecked the valves agin and found the clearance to be 0.018, put back to about .006, still loud. Have adjusted valve 3 times this year so far. Can this be the rockers or valves wearing?
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At .006" did it sound any quieter? When mine were at .006" it was still too noisey for my liking,so I set them at a tight .004" HOT.Much better now.
No. It didnt sound any quieter at all. The strange part is that I had adjusted them just a few rides earlier also. Im going to check them out again now that I have about an hour on the engine since I last adjusted them. going to look at everything for wear, check pushrods for straightness also. Who knows whats happening now that the machine has been underwater a few times. If all looks good then I will try to adjust them tighter and see what happens.
I use a mechanics stethescope for listining to noises. You can almost pinpoint the noise with it. Sears or your parts store has them.
I may have to get one of those stethescopes.
I rechecked the valves today after an hours ride. Still at .006 I reset them to .005. I checked the pushrods for trueness, rockers for wear and valve stems for wear. Everything checks out. Still makes noise. I may have to look farther down. May pull the head/cylinder this week adn see if maybe the piston pin is loose or something is off in there.
I had this problem on my old 450, i adjusted the valves till i was blue in the face with no luck. It ended up being the lower bearings on the crank. Not a fun fix.
I hope thats not the problem. I already put a new top end on it about 1000km ago. guess ill do what i have to to get it better.
why was it rebuilt? did it rattle before the rebuild? there are a few different things it could be. timing chain, chain tensioner, valve seat came loose, crank
It was rebuild after i sunk it in a river a few times. Lost compression. Found a scored cylinder. New piston, bored cylinder,rings. Crank looked fine. It did rattle a bit before the rebuild nothing major. After the rebuild it made a different sort of noise at full RPM/load. Kinda like detonation from low octane gas. Put in premium and made no difference. Some told me it just makes that sound. Now its louder and a steady noise. Might have to make a sound clip to post. Im hoping not timing chain as that seems difficult to get to while the engine is in the frame and it does seem like its higher up in the engine.
What ever you find, please keep us updated.
my guess is the bearings. Mine was fine till i sunk it, rebuilt the top end, and noise never went away.
will definitely keep updated. Im going to get a set of top end gaskets this week and pull it apart again. Im hoping to find a bad wrist pin or something easy like that. Can I check the chain tensioner while the engine is in the fram or do I have to remove it or everything else to get in there?
I grabbed a mechanics stethescope and listened to the engine and I can definitly hear the noise when I listen to the valve cover. I hear nothing unusual from the engine casings near the middle and bottom. I only seem to hear it as I hold to the valve cover or a little when I hold near the sparkplug. Everything in there seems good. Could low oil pressure cause this? Engine does knock when the idle is low, I have to blip the throttle when I start it and then it sounds better at idle. I just increased the idle
450 rattling

I have a 2004 450es. It started making the a top end noise after riding hard all weekend. The noise came on all at once and the bike lost power. The noise is a ticking, not a knock from the crank. I have already taken apart the top end and found nothing out of the ordinary, including the crank bearing. I am resleeving the cylinder and going back to a stock piston. The head is also being redone. My next step is the timing chain and tensioner. This is where I think the problem is. Think I'll put a new clutch and kit in there while I'm at it. I love working on these things.
Noisy engine while at idle.

Hello guys I have a 03 Foreman 450 and I have problem with the rattle at low rpm's.It also rattles loud when it is first started and stops when you rev it a little.I have replaced the timing chain that was worn badly,Bored the engine because it was smoking as well.The tensioner is good and the crank bearings were in good shape on the front side of the engine.I only checked that side being it was off during the chain replacement.Valves are right ,the head is brand new and I still have a noise that sounds like a real loose rocker arm but somewhat different.OH !!! I forgot to mention that I have a new piston and pin in it also.I checked the rod for wear but it was inside the service limit so the stock rod and crank is still in it.I questioned the oil pump as well and pulled it apart and measured the clearance and all checked out good.Does anyone have a suggestion as to where I might find this noise?????????
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2001 Honda Foreman 450 ES
Did anyone ever hear rattling noises coming from your engine when going around 44 km/h and letting off the throttle a little? I just had to get a new piston, rings valve seals because the engine oil leaked out of the final drive shaft seal that comes out of the rear of the engine. The engine oil was disappearing and there were no leaks anywhere on the ground. Turns out it was leaking past the seal and directly into the rear swing arm's hollow tubing. When the guy took it apart the swing arm tubing has litres of engine oil in it. It was smoking really bad.
It runs great now but I can hear a slight rattle coming from the engine compartment somewhere. I can't hear it if I'm in neutral and rev up the motor but I can hear it when driving it around. Especially when on the road and giving it throttle. I thought it was the valve clearances. The mechanic set them to speck (.006) when he rebuilt the top end. I had him reset them again a little tighter to .005 but the noise is still there. Wondering if I need to break it in more or if there might be damage in the bearings (bottom end stuff). Hoping it goes away with break in. Any thoughts?
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