unusual engine noise


3 replies to this topic
  • gabyzf450r

Posted August 08, 2014 - 07:58 PM

#1

Hey everyone, i just bought a a new bike well newer to me its a 2000 yz426fm and I'm a bit concerned with a noise (best explained) as a rattling noise or a constant ticking. the bike never made the noise when i bought it and that was two weeks ago. it started slowly and now it is constant hot or cold at idle and at high rpms i dont think i have even put 100 miles on it. I thought it might have been one of the few issues that others have encountered with these bikes, so i took it to a so called reputable mechanic to get it fixed here is a exact list of what they claimed to do

 

Removed fuel tank assembly and valve cover

Checked valve lash

Intake .006 and exhaust .010-both within spec

Check timing chain tension-good

Checked cams-good

Reassemble valve cover and re install fuel tank assy,

Check oil level and condition-good

Remove RH side cover, clutch assy. and check counter balance shaft key-good

Check both sprocket nuts-tight

Re bend washers

Reassemble and re install clutch-good

Re install side cover

Refill anti freeze and case oil

Nothing found out of spec.

Good to go at this time.

 

They charged me $232.77 for that and the bike is still making that noise to me it sounds as if its getting worse I'm scared to ride it any more I've heard horror stories about what happens when you let something like this go. Please if any one has some real advice, past experiences or ideas about what else it could be it would make my day.

 

thanks



  • indy rider

Posted August 09, 2014 - 04:26 AM

#2

Not sure if it's what you're experiencing but about 10 hrs after my last rebuild, I had a crank bearing race start to come apart. There was a repetitive ticking coming from the cases that continued to get worse. Of course, I wasted a bunch of time trying to diagnose the problem w/o splitting the cases but eventually had to. Swapped in a new bearing and changed the oil a few times and its been golden ever since.



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  • gabyzf450r

Posted August 10, 2014 - 08:00 AM

#3

well after about a days worth of investigating like starting it letting it idle and listening for the noise in every region of the motor i think I've determined that it is coming from the head. I've heard that this model bike has kind of a noisy valve train and I've also noticed when the engine gets really warm it gets louder. oh and i found another clue that points me towards the valves i shut off the motor and let it cool a bit was going to start it again and did the usual method pulled the comp. release and it accidentally slipped it made the same ticking sound so can that be the culprit? does the comp release just make noise or is that something i need to chase? I'm new to these compression releases so please fill me in.    

oh and thanks indy rider for the idea i really hope that Isn't the cause of my sound because that can get expensive fast hahah plus I'm not seeing any metal in the oili just dont think thats the cause.

 

thanks



  • G-BRO

Posted August 16, 2014 - 08:04 AM

#4

My bike did this a while back. Almost exactly what your describing. It happened a few hours after I changed a few valve shims. Turns out one the intake clearances was a little loose. I reinstalled a different shim and the ticking went away.
I'm not very familiar with the 2000 426 but from memory I believe the 2001 426 valve Clearances are .10-.15/.20-.25 for intake and exhaust.

If I was paying someone to do a valve check I would want each individual valve spec listed and, if adjusted, what the new clearance is. Valve ticking is extremely common in these bikes





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