HELP... tap I can make go away

[MtnEX]

Crap... I got a tap...

It will tap when I first crank it up, even if I let it warm up a while, keeps tapping.

I can mess with the throttle though and make it go away... rev it a little real quick just right.

I noticed it first when I changed the oil over to Mobil 1. So it could be more audible with the synthetic (heard that's common). But I do believe something is wrong... not blaming the synthetic at all. I wasn't even the last one to ride it before the oil change.

So what could be the cause of this tap?

[drew416ex]

Sounds like the valves are out of adjustment.

[MtnEX]

Originally posted by drew416ex
Sounds like the valves are out of adjustment.

That I can handle... I'd just need to know what type//brand guages to get for setting the specs.

[drew416ex]

You just need a good set of feeler guages. Not sure if any brand is better than the other though.

[MtnEX]

Originally posted by drew416ex
You just need a good set of feeler guages. Not sure if any brand is better than the other though.

Looks like they need to be a bent set.

I'll look for and pick up a set while taking time to order and wait for the new o-rings and so forth.


I hope that is all it is... but I guess it is also possible it might be nearing time to rebuild. It would just kill me if it becomes a MUST before winter is all.

[drew416ex]

They dont have to be bent, but I guess it couldnt hurt.

[wvspeedfreak]

Originally posted by MtnEX
Crap... I got a tap...

It will tap when I first crank it up, even if I let it warm up a while, keeps tapping.

I can mess with the throttle though and make it go away... rev it a little real quick just right.

I noticed it first when I changed the oil over to Mobil 1. So it could be more audible with the synthetic (heard that's common). But I do believe something is wrong... not blaming the synthetic at all. I wasn't even the last one to ride it before the oil change.

So what could be the cause of this tap?

It could be the decompressor sticking.They will do what you are describing.

[dariusld]

Originally posted by MtnEX
Looks like they need to be a bent set.

wait for the new o-rings and so forth.




Other then tools, you don't need any parts. Make sure adjust them right. If you don't, you'll think something else is wrong, when you just didn't adjust them right the first time. I'm just saying that because thats what I did, I figured out later I was using the wrong size feeler guage. They were old and I couldn't read them:rolleyes:

[MtnEX]

Well, I stripped it down to do the valve adjustment.


All 4 seem already good. The intake valves won't accept anything larger than .004 and the exhaust valves won't accept anything larger than .005. They are snug to these measurements on the guages.

I even turned over the engine a few times and rechecked and rechecked again, thinking I might be TDC on the wrong stroke. But I'm thinking I couldn't get the gages in if I weren't... or am I wrong about that?

The engine sprug through the other part of the stroke so quicky it was really hard to tell where I was... Once it got to a certain point it would spring on around by itself, which I couldn't stop while using a socket ratchet.


So unless I have done something wrong here... I don't think the noise is coming from excessive valve lash.

[MtnEX]

Originally posted by wvspeedfreak
It could be the decompressor sticking.They will do what you are describing.

So how do I check that? And what would I do about it if it was?

[hypersnyper6947]

The de-compressor is right under the cam almost, i dont know how to check it but i know where it is, i had to take mine out for the stage 2 cam.

my brothers decompressor stuck open the right exhaust valve twice bending them both times. Those things worry me aftermarket cams make the motor more simple which means less can go wrong.

[MtnEX]

Well dang.....

All I know is that I am worried.
But I hate to go any deeper in when it could be nothing.

I worry about something going south in the valvetrain...
And I worry about top end lubrication (oil pump/oil pressure)...

When it comes time to change oil again, I think I will pick up 2 qts of dino 10w40 or 10w30 motorcycle oil... just drain the syn 20w50 and see if the sound goes away.

If it does, I'll know it's either the synthetic making it more audible or top end lubrication issues. I'll drain the dino right away, pull the filter and put in some 10w40 syn to see what happens.

[blaaze416]

^^^ Yeah, tell me what you find. Mines got one heck of a tap, too. I just put in some full syn 20-50, and it the tap seemed to get louder! So that's not helping the diagnosis. Valves have been adjusted and re-adjusted. I thought maybe my rockers were gettign some wear, but really don't know what to look for. Would that cause an unusual tap, or not, and how do you know when thay are worn or bad?

[MtnEX]

Originally posted by blaaze416
^^^ Yeah, tell me what you find. Mines got one heck of a tap, too. I just put in some full syn 20-50, and it the tap seemed to get louder! So that's not helping the diagnosis. Valves have been adjusted and re-adjusted. I thought maybe my rockers were gettign some wear, but really don't know what to look for. Would that cause an unusual tap, or not, and how do you know when thay are worn or bad?

OK then, so then tell me this...

Has your aftermarket piston been in there long enough for it to be the wrist pin? Or is it not real likely?

Does your noise go away ever?

[blaaze416]

Originally posted by MtnEX
OK then, so then tell me this...

Has your aftermarket piston been in there long enough for it to be the wrist pin? Or is it not real likely?

Does your noise go away ever?

Piston's been in there since april of 07. It had a tick, or tap, before I put in the piston, and after. I put in the cam later and the tap, (or tick) just changed...so i figured it was the cam and/or valves.
I honestly don't know much about the innards of the beast, so couldn't tell ya if it were a wrist pin. And no....my tick or tap is now always present. Before I got the cam....i do think that my tick went away when revved, but cam back on idle. If I adjusted the idle slower, it would go away.....sometimes completely. Then come back on occasion. I know...huh?!? :huh

[blaaze416]

I sometimes hear a 'knock' too at lower rpm's when giving it gas....wus up wit dat? Higher octane gas? I use 93.....

[MtnEX]

blaaze416,

I know... very annoying and confusing huh :huh

Well, here is all I have so far...
Piston wrist pin... or stock decompressor.

Since you got a new piston, you should have gotten a new wrist pin right? I mean surely it comes with it. This makes me want to rule out the wrist pin in a way.


However, if you got a new cam, from what I understand the aftermarket cams don't have the decompressor lobe on them? You shouldn't even have the decompressor in there anymore... unless it was left behind...



Daaaamn I'm confused.

[blaaze416]

I'd asssume when it was put together, a new wrist pin was installed. The decompressor is still attached to the stock cam, sitting on my shelf in the garage. I've checked the timing chain tensioner (good), timing chain is a HD chain (new), timing itself is right on, it's got a new top end (seals, guides, etc.) There seemes to be no unusual wear on the rockers and such. Valve springs all seem in order. At this point...unless someone can verify what a bad wrist pin's characteristics are, I think I'll just keep the oil clean and ride her til she blows! Although the tick (or tap) is pretty annoying at low rpm's, and idle..... even more so when it's warmed up.
I'm stumped!

[MtnEX]

Originally posted by blaaze416
I'd asssume when it was put together, a new wrist pin was installed. The decompressor is still attached to the stock cam, sitting on my shelf in the garage. I've checked the timing chain tensioner (good), timing chain is a HD chain (new), timing itself is right on, it's got a new top end (seals, guides, etc.) There seemes to be no unusual wear on the rockers and such. Valve springs all seem in order. At this point...unless someone can verify what a bad wrist pin's characteristics are, I think I'll just keep the oil clean and ride her til she blows! Although the tick (or tap) is pretty annoying at low rpm's, and idle..... even more so when it's warmed up.
I'm stumped!

I dunno.... I really don't....
I'd love to hear yours in person to see if it's really the same sound.
I believe it is....

It doesn't sound like valve chatter. It sounds serious. It's a tap/slap/knock type of sound... not a chatter. The noise seems high in the engine and seems to be coming from one single thing. One valve, one rocker, one lobe, etc...

Anyways, tell me one more thing... do you have the decompressor spring and pin out of the engine?

[blaaze416]

God I hope so! When i did the cam swap...I did it by the book, and the instructions that came with the cam. So I'm pretty sure I got em both out of there.
And yes, the sound comes from high on the engine. I can't tell if it's stronger on one side or not....I think it's pretty equal. I don't have a video camera, just a digital. Maybe I can take a vid on that...though the sound may not be that good, defeating the purpose. Getting ready for a home town baseball game..so maybe when i get back.

[MtnEX]

I forgot to add that mine does still come and go like yours used to.

When I crank it up... it's that sound like something's not getting oiled. But it doesn't go away quick like that does... just keeps tapping. It has Mobil 1 synthetic in it... the 20w50 V-twin... and I noticed the noise at first start after changing to this oil.

You know... I hate to waste $18 worth of oil that is probably fine..
But maybe I should try something else.
I have 2 quarts of the 15w50... or I could get 10w40...

Might run seafoam through it if I decide to drain the 20w50.
I dunno.

I hear it mostly at idle and here and there when riding.
Thought about mixing in some race gas to rule out any octane ping.


Today, it stopped and then came back at idle sporatically... rattle rattle... quiet a bit... rattle rattle rattle... and quiet for a long time.

I can't really tell where my noise is coming from either. Sounds a little stronger around where my headpipe runs on the right side... but could be because the pipe is there.

Oh well, gotta go to work tonight.
Better run.............

[blaaze416]

That's it. I'm gonna have some time to spare in the next week or so. I'm gonna get some micrometers and check some things...rocker shafts, arms, cam lobes and anything else I can figure out how to measure and inspect. I have a slight oil leak at the rocker arm shaft seal on the outside of the cover, and have had the notion that this may be an indicator of something more...?? I guess I just have a hunch my problem lies with the rocker or shafts having worn. It would make sense according to your 'one thing' theory. It may just be one rocker that has worn a spot on the shaft and 'shift' every time it comes around. And mine is worn more than yours, so yours stops every now and then when it finds the right 'frequency'. I'll tell ya what I find and how it goes.
oh, btw...I haven't got a photobucket account yet, and haven't figured out how to post a pic yet....so, it may be a while on the video. I'm lazy like that...;) .

[krt400ex]

Originally posted by blaaze416
I'd asssume when it was put together, a new wrist pin was installed. The decompressor is still attached to the stock cam, sitting on my shelf in the garage. I've checked the timing chain tensioner (good), timing chain is a HD chain (new), timing itself is right on, it's got a new top end (seals, guides, etc.) There seemes to be no unusual wear on the rockers and such. Valve springs all seem in order. At this point...unless someone can verify what a bad wrist pin's characteristics are, I think I'll just keep the oil clean and ride her til she blows! Although the tick (or tap) is pretty annoying at low rpm's, and idle..... even more so when it's warmed up.
I'm stumped!


bigger cams will make more noise. that is just the way it is. my top end has like 300 hrs on it (im just waiting for it to blow) and i have a nice tick that is worse at lower rpms than anything

[400exrider707]

My 400ex with a stage 1 cam sounded like it was going to blow apart. The stage 1 hotcam was one of the loudest ticking cams I ever heard in a 400ex. It ran awesome and I ran it hard for a good year before selling it. The ticking never went away, and it got really loud when the motor warmed up, which made even less sense to me. Just apply liberal amounts of right thumb and forget about it!;)

[MtnEX]

I did the wooden stethescope test on mine.

It's remarkable what you can hear that way.
But I still was not able to pinpoint spot of the noise.

Pretty frustrating considering I could even hear fine details like the timing chain.

Originally posted by blaaze416
I sometimes hear a 'knock' too at lower rpm's when giving it gas....wus up wit dat? Higher octane gas? I use 93.....

really? 10:1 with the timing key knocking? I thought predetonation normally occurs at higher RPM not lower

[swva350x]

could be the timing chain, they make a good sound, when they are worn out. but it could have jumped time too,

[blaaze416]

Originally posted by krt400ex
bigger cams will make more noise. that is just the way it is. my top end has like 300 hrs on it (im just waiting for it to blow) and i have a nice tick that is worse at lower rpms than anything

That's always been my excuse not to tear into it too much. It still runs great....it's just loud. Well, guess I'll just keep doin what I do best....apply liberal amounts of right thumb to drown out the tick!

MntEX, that may be all there is to the mystery....just a loud cam for me. For you, I suggest getting a cam, if you don't already have one. I figure, you already have a loud ***** tick anyhow....might as well coax a little more from your engine, and eliminate the decompressor mech' from the equation at the same timen. ;) :D

[krt400ex]

Originally posted by blaaze416
That's always been my excuse not to tear into it too much. It still runs great....it's just loud. Well, guess I'll just keep doin what I do best....apply liberal amounts of right thumb to drown out the tick!

MntEX, that may be all there is to the mystery....just a loud cam for me. For you, I suggest getting a cam, if you don't already have one. I figure, you already have a loud ***** tick anyhow....might as well coax a little more from your engine, and eliminate the decompressor mech' from the equation at the same timen. ;) :D


haha, well my tick is on a stock cam. i think it is more chain slap from the cam chain than anything. i really should replace it, but i have more important things to spend ym money on right now and i am not rly riding the quad much since i bought the dirtbike.

[MtnEX]

Originally posted by MtnEX
I did the wooden stethescope test on mine.

It's remarkable what you can hear that way.
But I still was not able to pinpoint spot of the noise.

Pretty frustrating considering I could even hear fine details like the timing chain.

I'm going to try to find an exploded view of the engine and take it out there with me to try again. It might help me do a better job of checking with the wood.

Right now I'm thinking it is coming from very high on the right.
I might be able to tell more if I could get to the very top of the motor while running.

[blaaze416]

Been there....just take off the plastic, the gas tank and shield, then position the gas tank so you can hook the gas line back up, and start her up. I've done exactly what you're wanting to do and really found nothing that would help.....it was still loud...I still couldn't pin point where the sound came from....and I still had to put it back together sooner or later. :confused:
Just trying to save you some extraneous steps.

[MtnEX]

Originally posted by blaaze416
Been there....just take off the plastic, the gas tank and shield, then position the gas tank so you can hook the gas line back up, and start her up. I've done exactly what you're wanting to do and really found nothing that would help.....it was still loud...I still couldn't pin point where the sound came from....and I still had to put it back together sooner or later. :confused:
Just trying to save you some extraneous steps.

Well, I went back in for some more checking... did some things I might shouldn't have, etc.... but I have it where I can listen now and will see what I can hear during daylight hours.

[hypersnyper6947]

I just rode mine after the 450r carb install and it would knock a little at low rpm when i would give it a short small burst of throttle. Never did this before the carb, i had a lectron before. It runs great, should i be worried? I figured since we're talking about noises here not trying to steal the thread.

[MtnEX]

You'll need to get a sparkplug reading with that new carb first.

I'm not too impressed with the looks of the plug I removed tonight.
It's mighty BLACK!

Pretty worried about what all fell in on top of my piston when I removed it too.
Talk about a stupid F'in design..... STUPID!!!

[blaaze416]

So I went back and tried my metal stethoscope the other night. I got to the front right rocker plug and heard a metallic sound in sync with the tick I hear from the outside. So whatever is making my sound is coming form the right exhaust port side. i did not hear this on any of the other plugs. I also took a video with my digi camera, got a photobucket account, downloaded some pics....but can't find the video now.

btw,, what do you mean by stupid design? Basic, yes...stupid I'm not so sure.

[MtnEX]

Originally posted by blaaze416
So I went back and tried my metal stethoscope the other night. I got to the front right rocker plug and heard a metallic sound in sync with the tick I hear from the outside. So whatever is making my sound is coming form the right exhaust port side. i did not hear this on any of the other plugs. I also took a video with my digi camera, got a photobucket account, downloaded some pics....but can't find the video now.

btw,, what do you mean by stupid design? Basic, yes...stupid I'm not so sure.

I did the same with wood.
I ended up in the same area too.
I couldn't hear it exactly to say it absolute.
But if it's coming from the top end, it's the right front quarter.

I figure it's just the decompresser contact points clacking.
But then again, some say they have this with no decompression.

So it could be the timing chain slapping the tensioner.

****************************************

As for the stupid design... I was talking about the spark plug location. Yeah, down in a small hole in the FRONT of the engine is the perfect place for a spark plug opening in the head of an off-road engine... right where it collects dirt, tiny rock bits, etc...

[drew416ex]

Originally posted by MtnEX
I did the same with wood.
I ended up in the same area too.
I couldn't hear it exactly to say it absolute.
But if it's coming from the top end, it's the right front quarter.

I figure it's just the decompresser contact points clacking.
But then again, some say they have this with no decompression.

So it could be the timing chain slapping the tensioner.

****************************************

As for the stupid design... I was talking about the spark plug location. Yeah, down in a small hole in the FRONT of the engine is the perfect place for a spark plug opening in the head of an off-road engine... right where it collects dirt, tiny rock bits, etc...

If you think that sucks, have you seen where they are on a yamaha 450. You have to remove the gas tank to get to it.

[blaaze416]

At least now you are aware of it, and can prepare for it the next time. And yes, it is a bother, but as the wise and almight G.I. JOE once said, "...and knowing is half the battle!".

:D

(I've used a shop-vac to 'suck it up'.)

[MtnEX]

I've messed with this thing so much I've gotten really good at getting the noise to go away. I just put my thumb on the very tip of the throttle and give it a quick snap-slip.

[MtnEX]

I put up a video of how it sounds now that I've changed to a different type and viscosity of oil.

Check it out....
http://www.exriders.com/vbb/showthread.php?s=&threadid=364729

[MtnEX]

Well, I'm going around trying to UPDATE and I have now realized I'm going to pull a bunch of old threads up from the dead, and maybe even annoy some people in the process, but I feel it's worth doing...


The noise heard in that video is actually coming from the decompressor mechanism from the stock camshaft.

I have now had this professionally verified TWICE...

And after the second time around and also being in the process of carb work, I understand why.

What is happening is that... due to changing conditions.... atmospheric, and also things like fresh oil changes.... what is happening is that my engine RPM is fluctuating through a range that is getting my decompressor started clacking... That's why it comes and goes.

My carb has not been quite right since I had the work done on it, and I'm in the process of trying to correct that now.

If I can stabilize my idle, and then adjust it above this RPM range, I should never hear it again.

So nothing is wrong with my engine.... nothing is going bad or torn up.

And not only is that so... but it is obviously so.... because it has been doing it a YEAR now.