View Full Version : Strange Sound.

03-14-2012, 02:28 PM
So as some of you may know I have been trying to tune my bike since the 515cc kit build. I recently found out I have the wrong spark plug... pics and info below. I fixed that issue and fixed timing to match new plug but now I got another weird sound which i thought was just a primary adjustment but no matter how I adjust primary it doesn't go away... I am stumped on what it could be... Hoping its nothing serious... also since the new plug and fixing timing I have a strong vibration at idle... not sure if this is normal with b50 cams and 515cc kit since this is the first time I kinda got it running good....

This plug was an NGK IR (KR8AI) but completely wrong number.... for an arctic cat.. not sure how this mistake accrued I cant find the receipt on where i bought it.... as you can see its kinda burnt up and distorted... I am running NGK copper plug 1 step colder right now.

http://hostthenpost.org/uploads/f69c6753b08352f55729ec16c72d1b0a_thumb.jpg (http://hostthenpost.org/uploads/f69c6753b08352f55729ec16c72d1b0a.jpg)
http://hostthenpost.org/uploads/e346a1c80c1b502b50ba3c7d5cef3dea_thumb.jpg (http://hostthenpost.org/uploads/e346a1c80c1b502b50ba3c7d5cef3dea.jpg)
http://hostthenpost.org/uploads/67f676144ee8de62cce3700d89156787_thumb.jpg (http://hostthenpost.org/uploads/67f676144ee8de62cce3700d89156787.jpg)

03-14-2012, 02:44 PM
Do you have a sound clip of the noise?

03-14-2012, 02:51 PM
Some sounds clips of the clunking... you can hear the clunk as I move it around. the primary is more of a rattle not a clunk. this almost sounds like valve tap... but its fine when I am riding or I cant hear it over exhaust.

Clunk (http://youtu.be/Xi4ctr86_fQ)

Clunk (http://youtu.be/eUUqCKQjj-Q)

03-14-2012, 03:03 PM
piston hitting a valve??
Use any oil??

03-14-2012, 04:13 PM
I don't think its a piston issue or it wouldn't run strong and I would think the sound would get louder at higher rpm's which it doesn't mostly idle.

I was wondering could having the clutch cable too tight cause this ?? because i noticed it also has a rubbing sound when i let the clutch out slow on acceleration. but that was after i started messing with primary adjuster which I could of caused that issue myself.

that loud ticking makes it really really hard to do primary adjustment since it blocks out all other noises.

03-15-2012, 06:02 AM
Its not the piston hitting the valves, that is much more violent sounding, and has a higher pitch to it. This is what that sounds like: (unfortunately that was my motor when the valve guide broke off into the engine and the piston was slamming it against the head)

http://www.youtube.com/watch?v=9vD7v6_xzcQ&context=C498196dADvjVQa1PpcFOXCP2ToHbZjRWPuxHWu0pv KYVFZFqulow=

Let me think about it .....

03-15-2012, 06:06 AM
You know - it doesn't sound all that different than my 515 at idle.

Take a listen:

http://www.youtube.com/watch?v=K5XkpC1KqN4&context=C43cef8dADvjVQa1PpcFOXCP2ToHbZjRAEVQgGzWeh 9y-h59qsE6E=

And thats with the B70 cams, iridium plug

03-15-2012, 11:31 AM
Hey pierce how far did you need to advance or retard your timing.

Right now I am running B50 cams with 45/175 1#8 washer shimmed needle. I am slightly left of center with dots for timing.

I was thinking it could be push rod making noise maybe ??

its very close to your sound but mine seems a little higher pitch then that. also do you have a vibration in your footpegs worse then stock vibration ?

03-15-2012, 01:42 PM
I slightly retarded my timing - and I am using curve 6 on the SE ignition with 8K limit in place. I have the DAJ, but still I am at 45/170 shimmed needle. When I didn't have the DAJ I was at 178 so I made two steps back.

I don't remember having any out of the ordinary vibrations. I do have rearsets, can't remember if you do or not.

Personally I think you are fine. My blast is so jacked up I am always paranoid about every noise it makes - and these singles are noisy, so it seems like I am always listening to the engine. Perhaps you suffer my same fate of being over analyzing it.

03-15-2012, 02:33 PM
Hard to tell from that video, but if you cant hear it obviously over the exhaust you may be fine.

I know when i swapped in a 4k mile donor motor into my xb12 i was so paranoid about the sounds it made, but alas its just a noisy SOB. 2k miles later it sounds the same and runs the same.


03-15-2012, 07:39 PM
It could be I am paranoid since so many issues have come up on this build I dont want anything to happen to it. the clunking is slightly louder then the exhaust when you lean down towards the bike but when I am on and riding its not so bad and i noticed if I hold the throttle a little it gets less.

It is prolly just the sounds of the cams since nothing is like stock. I just gotta dial in the timing a little more and I will prolly be good to go. I know its not right because after about 20 mins of riding i get some smoke out of breather. I know there is will be some but I can smell it getting hotter then normal. prolly too lean on top end still

now my other question is how can i adjust primary without sound method because i honestly cannot hear it any more over that noise... and i dont want it too tight or to loose. can you measure bolt length to get it close ?

03-15-2012, 08:13 PM
You can't adjust by measuring it.

That noise it that loud? Perhaps you need to post a better video. I can clearly hear my primary even at idle sitting at a stop light.

03-15-2012, 08:21 PM
A more accurate sound of my bike at idle is this:

here (http://www.youtube.com/watch?v=_yQ7zVtavRU&context=C42f56fdADvjVQa1PpcFOXCP2ToHbZjRRIwhL2pPJw R2PXI2gHgPw=)

03-15-2012, 09:24 PM
Yeah mine is pretty loud, which was why I don't think this time its just paranoid. I will try to use my camera instead of my phone and see if the quality gets any better. yeh I used to be able to hear the guide touch the chain but now I cannot. its weird. wish you guys lived closer to me I got no blast members local to me lol

03-17-2012, 08:17 PM
Going to attempt to get another video tomorrow for you guys so I can figure out if its just me or not lol

03-17-2012, 08:27 PM

I have that same click/knock, can't hear it in my video. I've had it for YEARS.

03-18-2012, 01:55 PM



03-18-2012, 10:27 PM
I have a slight version of that as well - primary -