Timing chain noise


8 replies to this topic
  • averagebloke

Posted February 15, 2007 - 02:42 AM

#1

Hi all, I'm fairly new here, and relly enjoying the forum. Sorry if this is an old question. I've looked back through old posts but haven't found anything that answers my problem.

I've got a '01 426 that i've had for 3 months but haven't used it much yet. Absolutely love the bike, but the cam chain is very noisy. I removed the tensioner and checked and cleaned it. It appears to be good. The noise remained so I replaced the timing chain with a new OE one. And still the noise remains.

I know these engines are noisy, but a mate has a similar 426 and his chain is more or less silent, before and after his rebuild (3rd gear dogs worn).

I will check the chain for slack at the front and cam timing again as it was my mate who didi the final assembly while I was away. Though I'm confident he's got it right.

I'm concerned that if it's slapping around there could be enough slack for it to jump a tooth, and then... That's why I haven't ridden it much.

Sorry to go on, but I'd really appreciate any comments. Cheers.

  • 642MX

Posted February 15, 2007 - 08:12 AM

#2

Have you checked your valve clearances? I've heard some rattles that sounded like a chain and it was just a little excessive clearance.

  • averagebloke

Posted February 15, 2007 - 08:32 AM

#3

I've checked clearances, they're ok. The noise is 100% timing chain. Thanks.

  • grayracer513

Posted February 15, 2007 - 09:05 AM

#4

Are you certain it's the cam chain? It might be is a loose primary gear bolt, or a loose stator plate. Try and isolate the sound and the circumstance under which the noise occurs, then open the engine up and locate the source.

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  • averagebloke

Posted February 15, 2007 - 09:13 AM

#5

The noise is from the left side of the engine and is present from cold and stays when hot. It rises and falls with the revs, whether in gear or in neutral.

If the crank sprocket is worn would this realistically make the chain noisy? I'm guessing it would have to be very worn.

Thanks for the replies so far.

  • grayracer513

Posted February 15, 2007 - 09:42 AM

#6

If the crank sprocket is worn would this realistically make the chain noisy? I'm guessing it would have to be very worn.

It could, or vice-versa, the chain could be very worn, making the sprocket noisy (and wearing it out).

You should inspect this right away by removing the flywheel and stator. The crank sprocket is curt directly on the crank, so a worn sprocket means a crank replacement or rebuild.

  • averagebloke

Posted February 15, 2007 - 11:39 AM

#7

Thanks Grayracer. I've fitted a new chain already. I will take the flywheel off tomorrow and re-check the sprocket. I hope it will be conclusive either way. Though I don't want to have to buy a new crank.
I just wondered if the chains were usually noisy on the guides etc?

  • grayracer513

Posted February 15, 2007 - 12:21 PM

#8

Could be, or the guides could be worn, broken or out of position. Another thing to be sure of is that one of the half moon cam bearing locating rings hasn't gone missing and ended up in around the flywheel, and perhaps allowed one of the cams to be installed off of the proper center, letting the chain drag on something as a result.

  • aniesigh

Posted February 15, 2007 - 01:00 PM

#9

half moon locating rings are both there as i was the one who installed the new chain, stator bolts all tight. anyone had or heard of worn guides?





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