HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
RWYZ450F

08 Yz450f Engine questions

4 posts in this topic

Shop says I dropped a valve and it ruined the head. I have probaby 300-350 hours on the bike. They inspected the bottom end and say that there isn't any play in the crank (or is it the rod down there?). With as many hours as I have on the bike, I am afraid the bottom end won't hold up much longer but I base that on a few friends giving me their non-mechanic opinion. If they've inspected the bottom end and say it's good to go, do I have any reason to worry or will it go before it shows any sign of wear? This is my first and only bike and I'm rather uneducated with the engine internals.

 

I'm not sure I can justify spending more than $1,000 on the repairs. If it rises above that point, my gut tells me to sell it as is and get what I can for it then go get another bike. Or part it out. I expect to hear today or tomorrow from the shop to let me know the damage$$$.

 

Thanks for your time and input!

 

Ryan

Share this post


Link to post
Share on other sites

If there is no play in the crank then you are good. 300 hours wow. Please do a top end rebuild before a valve or piece of piston chunk off into the bottom end

Share this post


Link to post
Share on other sites

If there isn't any play in the crank, then there's something wrong with it, since there is a specification for how much play there should be.

 

Nevertheless, the real problem here is that the piston has run into the head hard enough to make a mess of it. That contact may very well have "stamped" grooves in the crank pin and outer rod bearing race, and/or flattened some of the rollers in the bearing.  The crank should be carefully inspected for trueness, and probably torn down for inspection and possible rebuilding.

 

The head can probably be saved if sent to a competent shop such as EDCo.

Share this post


Link to post
Share on other sites

Well the 450 is shot. $1,800 is what all the work needed for it amounts to and I'd rather just get a newer Yamaha. I know this might be a new thread question but I'm hoping I can get a quick response from someone who knows a little bit about the 2011.

 

The shop I took my bike to has a 2011 Yz450f and it looks pretty clean. I'm going to ask them some questions about the previous owner and hours on the bike but otherwise, were there any problems I need to know about with the 2011? I loved my 2008. Never gave me one problem until this so I'd like to get back into another YZ if the newer ones are as reliable as the older. I searched through the first 4 pages of threads and didn't really see any problems noted. Any advice is appreciated.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0