2012 yzf450 cam chain skipped teeth


9 replies to this topic
  • MKM

Posted May 20, 2013 - 03:42 AM

#1

Hi guys on the weekend I started my bike in the morning fine twice. Then went to go for a ride, took it off the trailer started and within 30 secs it stalled then wouldn't restart but would turn over fine. When I got it home I tried to kick it over but was locked. Pulled the rocker cover off to find the cam chain loose and skipped 2 teeth. Adjusted to right marks and started for a sec but stalled after a few kicks backfired. The bike would of done between 40-50 hrs. Has anyone had any trouble like this?

  • NitrousR1

Posted May 20, 2013 - 05:17 PM

#2

I'd remove the tensioner and inspect it, make sure it is holding. Also not a bad idea to replace the cam chain, roughly $20 and cheap insurance. I sell one every time I do a valve adjustment as they do tend to stretch quick. Inspect the crank sprocket and both cam sprockets. Hard to believe they could be worn allready but could be if it keeps getting loose and jumping time.
I find this kind of odd for a 12 with these hours. I'm in charge of a group of 12's that get beat within an inch of there lives with just regular maintenance pistons and valves. They seem to be tanks and haven't had any problems with them. I'd suspect the tensioner

  • MKM

Posted May 20, 2013 - 06:08 PM

#3

Thanks mate. Yeah I couldn't believe it either. I bought one because everyone say how good they r. I was going to replace the chain a tensioner.

  • grayracer513

Posted May 21, 2013 - 07:10 AM

#4

Inspect the chain. If it skipped, you may well find that there are some links in the chain that are stiff and binding. These will play havoc with the chain tensioner, and can cause the sudden appearance of slack in the chain. I've never been able to categorically pin down a cause, but the only thing that seems logical is that it's a lube related problem.

  • MKM

Posted May 21, 2013 - 12:45 PM

#5

Yeah I am going to pull it down during the week and have a look. I change the oil and filter every 4-5 rides which is just bush riding.
Spoke to the bike shop and he said its unheard of for that to happen.
I'm getting a new chain and tensioner to put in and hopefully all good after that

Thanks for the replys

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  • grayracer513

Posted May 21, 2013 - 01:30 PM

#6

Every 4-5 rides is probably too long to go on an oil change, even with a good, durable premium oil.

This is not at all unheard of, though, outside the fact that this is the first of the Gen 3 450's I've heard of doing it.

  • drtrcr400

Posted May 21, 2013 - 06:53 PM

#7

Just wanted to add my own experience on this subject, first a little background. I have a 2012 YZ450 with 145 hours on it. I ride mostly woods and occasionally race GP's and XC's here locally, usually top 5 overall. My bike looks like crap but it's maintained very well mechanically IMO. Despite routine checks, it' only ever needed 1 very slight valve adjustment. I change the oil and filter on average every 6-7 hours and the bike gets a fresh aircleaner as often as necessary. I also perform lots of other routine maintenance but thats not important here.
I decided to replace the cam chain lest weekend just for peace of mind on an upcoming trip. I removed the old one and much to my surprise there were absolutley no kinks, I even tried to kink it and it would simply hang perfectly straight. Ok, I thought, maybe its stretched a little? Nope, holding the old and new side by side I couldn't see a difference at all. Oh well, I already had a new one so in it went.
I think Gray might be right and you could be going a little too long between oil changes. Another consideration is your crank breather hose. Has it been re-routed to the intake? I have seen times where sand, gunk, dirt can work its way up the tube and small amounts can get into the engine. Just a thought, it's highly recommended on this site and others...

Edited by drtrcr400, May 21, 2013 - 06:56 PM.


  • MKM

Posted May 21, 2013 - 08:14 PM

#8

Ok that was what I was told by the shop to change oil every 4-5 rides. How often would u change the oil?
Na the breather is still standard. Where would u re route it to?
Thanks for the replys guys.


  • grayracer513

Posted May 21, 2013 - 09:06 PM

#9

I decided to replace the cam chain lest weekend just for peace of mind on an upcoming trip. I removed the old one and much to my surprise there were absolutley no kinks, I even tried to kink it and it would simply hang perfectly straight. Ok, I thought, maybe its stretched a little? Nope, holding the old and new side by side I couldn't see a difference at all. Oh well, I already had a new one so in it went.
I think Gray might be right and you could be going a little too long between oil changes.


That's what mine look like when I replace them. I use a top tier full synthetic blended for motorcycles with shared engine and trans oil and change it every three rides unless I'm headed to a race. Then it gets new oil regardless.

  • KJ790

Posted May 22, 2013 - 04:57 AM

#10

I've worked on a lot of people's bikes with kinked cam chains, it is a common problem on all brands if the oil is not changed often enough or if the cam chain is run too long. I just worked on a KX250F that jumped time and the cam chain was so kinked I couldn't even straighten some of the links out at all. I'm not sure if the oil had ever been changed on this bike though. I haven't had any of the cam chains on my personal bikes kink using Maxima Premium4 or Shell Rotella T oil with 3 hour oil change intervals. I change my cam chains every 50 hours though just to be safe, it's cheap insurance.





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