2008 YZ 450 F Motor Failure

Personally, I change mine every 30 hours. I think 100 hours is pushing it considering what the chain costs vs. what it costs when the chain has a problem. It's only a 15 minute job to change, it's not a huge deal.

Personally, I change mine every 30 hours. I think 100 hours is pushing it considering what the chain costs vs. what it costs when the chain has a problem. It's only a 15 minute job to change, it's not a huge deal.

yeah I don't mind doing it. If you guys are replacing them that soon I guess I will too, cheap insurance!

I guess OEM is as good as anything right?

Since we are on the subject and I have never left an engine alone or had a bike long enough to have a chain failure but what is a good interval for chain replacement? I use MCF and change oil usually around 8 hrs sometimes less. Would a 100hrs be pushing it? I plan on full teardown at this time for preventive maintenance.

I normally replace a cam chain about once a year. It's never "needed" it, but, you never know...

They're cheap, and it's an easy job.

I normally replace a cam chain about once a year. It's never "needed" it, but, you never know...

They're cheap, and it's an easy job.

Once a year sounds good, it'll give me something to do when it snows. You doing tensioners too?

Back on subject did we ever get a failure confirmation, dropped valve?

I never used to on the older models (pre-'06) if it felt smooth, etc., but the tensioner was revised in '06, and I'm not sure I trust the new ones as much. OTOH, the new ones cost less. :bonk:

My '08 YZ 450 just dropped a valve and a little piece of the valve shaft hit every other valve in the head destroying all of them then the valve head bounced around in there for a second then came to a halt lodged sideways in its own port, so now need a head as well. To make matters worse upon inspection of the cylinder I noticed a 2" long hairline crack in the nik wall so thats junked too. I've owned the bike since new and installed an hour meter on it the first day which has 81 hours on it and am very religous at changing oil and cleanin filters but I kinda wonder if my old chain jumped creating this whole mess.

I post pics asap

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