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08-25-2001, 12:52 AM
Brand New 2001 400EX (1 month old - past break in period)makes a singular clicking noise every time you rev it up after engine reaches operating temperature. Talked to several service reps at dealer, head of service, GM of store and Honda Corp - none of them have heard of this problem before. It does not make this noise all the time only when the engine is hot and you have been through all the gears. Dealer serviced 3 times already!!! Did the following work - valves have been adjusted, dealer replaced spark plug,cam & compensator, starter clutch, piston pin, 2 different gears, clutch outer casing, 3 gaskets and a bunch of bearings. Run 91 octane gas only (highest I can buy here in Colorado other than racing gas)... Almost sounds like someone is tapping the engine case with a screwdriver. Can't pinpoint exactly where its coming from but you can hear the noise over the engine.

Guy400
08-25-2001, 07:11 AM
Is the engine broken in yet? After break-in you should definitely check valve lash as they may need adjusted. If the sound is real bad it could be a rocker arm that's a little loose. I know my cousin's 400EX makes a little tapping sound when you rev it up. I may be mistaken but I think that sound is a trademark of this engine. I've heard of numerous other owners talking of it.

08-25-2001, 07:28 AM
sounds like your valves need adjusting

4punksdad
08-25-2001, 06:23 PM
have you tried changing your spark plug? Maybe the "knock" you hear is unburned fuel. If it were valve noise it would not be a singular "tap".

Revin300EX
08-25-2001, 06:45 PM
Drain the gas tank and put some premium fuel in it... I bet it stops!

Winged Warrior
08-25-2001, 09:04 PM
I have tried everthing i think? Took back to dealer after making noise (month old) they couldnt find nothing wrong .drain all gas try dif gas twice. New plugs ect ect. still makes this noise still bugs me !:rolleyes: :mad: :( :blah :grr :confused:

Revin300EX
08-25-2001, 09:18 PM
Where exactly is it coming from? See if you can tell...

If you cant, go and get one of those mechanics stethoscopes, and start poking around with it.

If we know where its coming from, we can tell you what it is...

Guy400
08-25-2001, 09:47 PM
You don't need to go buy an automotive stethoscope, you already got one at your house. Take a broom handle and unscrew it from the sweep. Touch one end on various parts of the motor while you cup your hand around the opposite end of the broom handle and your ear. Voila, a free stethoscope! That's an old drag racer trick.

400exRacerX
08-25-2001, 09:57 PM
put super "93" octane gas in there, it sounds almost like its pinging to me

Revin300EX
08-25-2001, 09:58 PM
And if you cant find the problem, you can always beat it with the stick! Thats what I do! :huh

Guy400
08-26-2001, 06:59 AM
I can almost guarantee you the noise is originating in your valvetrain. WTH, go buy some of that racing gas and run it through your bike and see if that helps but I doubt it will. The ticking increases frequency when the engine is revved so this tells us it's in the reciprocating assembly. A main bearing going bad is a much heavier knocking sound so we can rule that out. Wrist pin area generally makes a heavier sound as well so that probably isn't the culprit either. Well what else spins inside the engine that's left? The valvetrain! It can be a singular tick and still be in the valvetrain. If it's just one bad rocker arm or one bad valve it can make just a single tick. Now, if the dealer is certain valve lash is correct we've got to look in other places. You added much more detail when you edited your original post so with the work you've mentioned the head has been off the bike. Did the dealer inspect the head? Is the seat ground right? Is the valve machined right? It is possible to get these machined incorrectly from the factory. Occasionally you get a head that shifted slightly during the machining process and your seats won't be 100% accurate. I've built more drag and street/strip motors that a person could count and I've seen this on some of the most expensive heads money could buy. We had a guy bring a motor in that he assembled and wanted us to run it on our engine stand so that we could break it in before he dropped it down in his car. We start this motor and there's a little bit of a tapping from the upper part of the head but just chalk it up to a motor that's a little tight, after all, this is it's first time being run. After about 20 minutes the tapping is still there so we shut it down and tear the valve cover off. Check all rocker arms to make sure they're tight and start it up again--still ticking. We checked out all the usual suspects and nothing to be found there. To make a long story short, we found that the #2 exhaust valvespring was bad from the factory. There was supposed to only be like 110# of seat pressure and this spring was around 130#. To make matters worse the installed height was wrong so basically this particular valve was trying to be closed farther past the seat than it was supposed to and with more force. We disassembled the head, checked all the springs, replaced that particular spring and fired the motor back up. Ticking gone.

You can have the dealer check your spring pressures, installed height, seat area, etc. but at this point if your dealer is acknowledging a problem and they've already done everything they think they can have them write a letter to Honda and replace your entire engine under warranty. Just get a new engine and let Honda R&D worry about finding the problem in the old one.

Sorry this post is so long but I know how frustrating this stuff can be.

Red Rooster
08-26-2001, 11:02 AM
Hey Revin,
I Know this is off subject but do you like your fast trekers rear tires?? How do they do in sand and snow compare to the stockers. Thanks. Sorry.

08-26-2001, 12:54 PM
Don't worry. My 02 400ex does it too. All the local dealers told me that it is just a trademark of some 400exs. They said some can be heard and others can't and that's its the oil being sent to the oil cooler above you oil tank. :D

08-27-2001, 09:54 AM
Guy 660R - I would like to say Thank You Very Much for the time and thought you put into your response.

It sounds like you know a lot and I think it is great you share your knowledge with people like myself who have to analyze everything a dealer/serviceman says to make sure I understand what they are talking about.

Again Thanks for all of your help - I really appreciate it.:)

Stunz
08-27-2001, 10:01 AM
Here is a long shot.
Check the two bolts that mount the heat shield to the exhaust pipes. It's right under your right knee. If one of those bolts gets loose, you win get a rattle sound. It's worth a check.

JabberJaw
08-28-2001, 11:17 AM
I like that broom handle trick, accept for one thing.... my head keeps sweeping from side to side...hehheheh