Clacking noise! Oh no!

On my way home from work last night I noticed a faint clacking noise developing. By the time I got home it was more noticeable. This morning I go over to the shop to attest the situation and boy was it noticeable now.

Oil level is fine. Adjusted cam chain tension. Sound is still there, and is really bad if you blip the throttle. Seems more evident under the front of the motor. I don't know if that's because the sound is reverberating off the floor though.

I took a short video with my wife's camera. The audio isn't that good, but I hope you can hear it as well as I can.

http://www.youtube.com/watch?v=lME0DCj8HKo


1982 XJ650 Maxim YICS

 

Hey Ved,
Have you tried removing one plug wire at a time while running. If noise goes away while particular plug wire is off, you can isolate which cylinder is causing noise. Doesn't sound too good, form what can be heard on vid.

 

Check the exhaust headers where they bolt onto the engine. I had something similar happen; one of the retaining nuts on the #4 pipe was loose and the other was just plain missing.

 

Thnx pbthoe, I'll try that.

It's definitely not the exhaust manifold.

 

sounds slow, about the same rpm as a rod maybe(hope not)

 

Tried pulling each plug wire one by one. As the idle dropped the ticking did go away, but bliping the throttle and the clacking was still there. Similar results for each of the 4 plugs. The sound does seem to be more evident on the right side, lower part of the engine.

I can get better audio with my daughters Itouch for some of you motor gurus if need be.

I am so bummed right now. Just got my wife a Honda 75 CB360T for her birthday and am about halfway through finishing the rebuild on it, and this crap happens to my bike. Ive never done a rebuild on a Yamaha, let alone one one with 20 valves on it... I am soo not looking forward to it.

 

i don't know if this will make you feel any better but your yamaha only has 8 valves not 20. Much less complicated then the xmotor. But still sucks .I am going to listen to it in a few min hopefully i can help

 

Are you sure you don't have a rust hole in the exhaust ? how many miles? almost sounds like your timing chain is stretched to the point the tensioner can't keep it tight when you blip the throttle its slapping around but hard to tell by the video. use a rod or stethoscope see if you can pin point it

 

I'm not %100 positive, but I don't think it's the exhaust.

36k miles

I also thought it may be the cam chain. This model has an auto adjuster for the cam, however I did try a trick I read in another post about getting it to auto-tighten and it didn't seem to help.

I tried the rod/screwdriver stethoscope idea and being the noise seems to be right behind the headers I can't get too close, and had a hard time pinpointing it.

I need to replace the valve cover gasket(was meaning too over this past winter) but didn't get a chance. If I remove the cover will I be able to check for slack in the cam chain, or at least see wear on it if it has been making contact?

 

Yes by the sound of the video, the rate of "clack" does sound like a rod bearing or cap screw that came lose (it happens) You will need to tear into it to make sure before riding it anymore. The damage may already be done.
I've had a rod cap come out the side of an engine once and it makes a loud "BANG" then the engine quits. Not a good day for me.

 

Ughhh. So much for the "bullet proof" engine...

Well it will be sitting for a while then if an engine teardown is eminent. With only 1 day off a week to work on anything, my spare time(and money) is very limited. I might just put it on CL as a parts bike and pick up something else next year with my income tax check. Probly go with another Honda. I paid 900 for the Maxim, with 32k, and barely put 4k on it since Ive owned it. Not sure I got my money's worth...

Thanks for your input guys. Always appreciated.

 

Another way to isolate a cylinder is with a timing light hooked to each plug when you get to the bad cylinder ( rod piston pin) the sound will be in time with the light you can also put an oil pressure gauge in the oiling system , compression test it. Sounds more like a valve than a rod to me. Good luck to you!

 

Thanks for the info waldo.

I just got off the phone with the resident motorcycle mechanic in this area and he said bring it by this weekend, and he'll poke around on it with his stethoscope. I'll also check to see if he has a timing light while I'm there so we can try what you suggested.

Here is a couple more vids I recorded. Maybe the sound is more distinguishable in one of these.

http://www.youtube.com/watch?v=rp9URX0vjXE

http://www.youtube.com/watch?v=Ry9filsufx4

 

It does sound different in those last recordings. I hope you isolate the problem and find a way to fix it without tearing it all apart!

 

FWIW it sounds like a bent valve to me. If you can get a really long screwdriver you can place it on various parts and hold your hand on the handle right against your ear and start to isolate it really good.

 

did you drain the oil to check for metal shavings?

 

Do the Engine Running, ... Plug Wire Removal Test.

If the knock goes away when a Plug Wire is removed, ... that usually indicates that you have >> "Spun a Bearing".

One of the Half Shells of a Connecting Rod Big-end escapes from its position and spins-down in front of the opposite Bearing Half-shell.

Caught in time to prevent serious damage to the Crank, ... you may be able to escape without having to replace the Crank.

Be sure what you are hearing isn't an Exhaust Leak disguising itself as Engine Knock.

 

Any news on this Vedalkin?

My Seca has the same ticking and I would appreciate any input on this matter.
Hope i don't need to split the cases.

 

I have a spare 750 Maxim engine here if anyone of you's need a crank or some parts out of it.

 

Sorry, no news yet. I am still working on my wife's 75 CB360 rebuild, so my time and money is kinda tied up in that at the moment. Once her bike is done I plan on pulling the valve cover off the Maxim, do a shims check, and see if the cam chain has any sign of damage. If nothing is found it seems my only resort is pulling the motor off and splitting the cases. I have a feeling I will have to do the latter.


Oh, and thanks PainterD, I'll get in touch with you once I find out whats wrong with it.