fresh rebuild motor noise.

[tripsover88]

hey everybody i just got my 01 400 rebuilt it now has a brand new Weisco piston (11:1) and bored out to a 416cc. stage 2 hotcam and hot rod (crank an rod were all ready installed before new rebuild along with the cam) i just got it back today and breaking it in (20 min at 1/4 throttle, cool off, 20 mins at 1/2 cool off ext... but never whent to full throttle at anytime.) my problem is that at certain engine RPM i start to hear a high pitched metal rattle noise but only near the mid rpm range once i go past that it goes away i thought it might be my chain (its worn out) but if i pull the clutch in the noise goes away. the motor runs real strong and not loseing power not smokeing and not popping threw the exshaust wich is a full Ducan fat boy 4 system, the bike is loud and i can hear the noise over that... my chain is a little lose and touches the swing arm guard but if it was that wouldnt i still hear it when the clutch is in? im gona go adjust it tomarow and take it down the road to see if i can hear it. is the noise normal for breaking in? any help with this would be great. thanks

[honda400ex2003]

imo it sounds like a new chain is in order first even if that is not the problem. although i think that would fix it. under power it puts load on it making it grind. It seems like mine has done it before when i needed a chain. I cant remember exactly though. that would be my first guess i suppose. then the valves would be next then the clutch plates in your basket with your basket getting too wore making the clutch plates slip and grind. when the clutch is in it takes the pressure off enough to get them to stop. might be worth looking into new plates also. steve

[99400esex]

It could be your chain bouncing off you skidplate, is the rubber guide still on the skidplate below the chain or is it gone?

[tripsover88]

Originally posted by 99400esex
It could be your chain bouncing off you skidplate, is the rubber guide still on the skidplate below the chain or is it gone?
the chain slider your talking about is missing and dose hit it.

but its weird it didnt start till after the rebuild or i didnt notice. i havent noticed clutch problems befor but ill look into it. thanks so far with the help.

[99400esex]

Well the noise your describing is the noise that comes from the chain slapping off the skidplate. It happened to my old 400ex and happened to a few of my buddies 400's. Maybe you just didnt notice it at first because I didnt really notice mine for a little while either.

[tripsover88]

ill take the swing arm guard off and see how it sounds then. but wouldnt i still hear the noise when the clutch was pulled in?

[99400esex]

No if you take the skidplate off you will most likely not hear that noise anymore, unless it is something wrong with your clutch but my guess would be the skidplate.

[killer400ex]

i bet its that thing on the bottom of the swing arm thingy that big metal plate that protects your quad hardware from rocks and stuff, i think its called a mid plate but idk maybe someone on here can refresh my memory of what to call it.........i dont think you guys stated enough about how it had to be the skidplate so i went ahead and helped u guys out all by myself

[99400esex]

Originally posted by killer400ex
i bet its that thing on the bottom of the swing arm thingy that big metal plate that protects your quad hardware from rocks and stuff, i think its called a mid plate but idk maybe someone on here can refresh my memory of what to call it.........i dont think you guys stated enough about how it had to be the skidplate so i went ahead and helped u guys out all by myself
I clearly said that it is most likely the plastic guide that fell off the skidplate. That would cause the chain to bounce directly off the skidplate and make that noise. Re-read the post

[dalejiw25]

It could be your chain bouncing off you skidplate.

[honda400ex2003]

Originally posted by killer400ex
i bet its that thing on the bottom of the swing arm thingy that big metal plate that protects your quad hardware from rocks and stuff, i think its called a mid plate but idk maybe someone on here can refresh my memory of what to call it.........i dont think you guys stated enough about how it had to be the skidplate so i went ahead and helped u guys out all by myself

pure brilliance right there. few hours late and a dollar short man. especially for such a dumb come back. you gotta have something good if you are gonna act like you own the joint. lame... steve

[99400esex]

Originally posted by honda400ex2003
pure brilliance right there. few hours late and a dollar short man. especially for such a dumb come back. you gotta have something good if you are gonna act like you own the joint. lame... steve

I see the sarcasm in that post now. O well you'll always have a leather cheerio or 2.

[tripsover88]

i took the swing arm guard off for now so i can see if thats whats causeing the noise. but i wont be able to check it till tomarow. (got to go to work soon) i hope its that simple and i dont have to go back into the engine to fix it.

[99400esex]

Originally posted by tripsover88
i took the swing arm guard off for now so i can see if thats whats causeing the noise. but i wont be able to check it till tomarow. (got to go to work soon) i hope its that simple and i dont have to go back into the engine to fix it.

Let us know how it goes!

[Racerjames]

Id like to think its chain related for your sake.
A question, what all was replaced on the motor rebuild? Any unusual running characteristics?

EDIT: I should be more specific. Are you hearing this noise during ramp up to WOT, or holding at the mid rpm range?

[tripsover88]

Originally posted by Racerjames
Id like to think its chain related for your sake.
A question, what all was replaced on the motor rebuild? Any unusual running characteristics?

EDIT: I should be more specific. Are you hearing this noise during ramp up to WOT, or holding at the mid rpm range?

well this is the story. when riding a few weeks ago and noticed it was down on power real bad. got it home and noticed oil comeing from between the head and case (blown head gasket) so i took it to my buddies shop and had him rebuild the top end (new gaskets piston and rings and had the cylender sent out to get bored to 87mm for the new piston. that all got back and put back togeather. while the bike was at the shop i baught a full skid plate ($20 used from craigslist) and front fullbore plastics (trade my stock race cuts for his) and took it for a ride. now while im in 5th gear at a good pace (not WOT) and crusing at that speed ill hear a rataling noice , if i give it gas and speed up it goes away...if i pull the clutch in it goes away... if i just back off the gas it goes away. only crusing at a constant speed will i hear it. im taking the bike back out tomarow for another ride this time with the swingarm guard off and see if its that and ill let you all know when i get done.

[416racer]

If you have a full frame Alum. skid plate, you might check it too. Mine makes noise sometimes that sounds like the motor is falling apart.

[Racerjames]

Sounds to me like a loose fastener somewhere, although you could prolly hear it at a standstill. (rev it up slowly standing next to the bike and see what you hear) Other than that maybe its noisy chain (near death noise) or is there any chance your timing chain tensioner is loose/out of whack? Hanging at mid RPM with a somewhat loose chain will cause it to "float" a little and make some noise. Just a thought tracing back to the similarities of a loose chain on a BMW inline sixer

[tripsover88]

sorry for the wait but i found out what the noice was. a lose frame skid plate. its allways the smallest things.

[honda400ex2003]

good to hear you got it figured out! steve