'10-'13 YZ450F questions

I've tried searching but wasn't able to find an answer.


I've often read that the old 5 valve motors in the '09 and older models are extremely reliable and hold their valve clearances very well if properly maintained (at least my '06 did). How do the new 4 valve motors compare?


Also, a bit of a dumb question, but do the fuel injected bikes pop on deceleration like the carburated models do?


I read that the new '14 model uses a wet sump system vs. dry sump. Would I have to worry about the engine not getting lubrication when doing wheelies? I used to wheelie my '06 for miles, but having a wet sump system would worry me a bit. Please chime in.


Thanks in advance!

Edited by MR2turbo4evr

2011 owner. 50 hours No maint needed.

I could count on one hand the number of "pops" my bike has done during deceleration.

Good luck with the dry and wet question.

I have a 2010 with 175 hours racing A class mx without the valves going out of adjustment. I had an 06 before this and it seems the 2010-2013 motor is just as reliable. The only problem I have seen is the waterpump seal goes out every 45-60 hours (just like the older generation motor) and I have seen multiple fuel pumps go bad at around the 100 hour mark. I have seen the fuel pumps go bad on all of the brands, so I don't think it is just a Yamaha issue.

I had one of my exhaust valve break at the keeper and fall into the cylinder at 145 hrs.  It hit the piston and bent the valve.  So I replaced both exhaust valves only to have the crank go out less than 2 hours of run time later.  I'm sure the big end rod bearing got damaged when the piston hit the valve.  That's the only problem I've had with the bike the whole time I've owned it.  I'm now going on 180 hrs with the stock intake valves and am about to reshim them for the first time.  I'll replace the intake valves this winter.  I think my valve problem was a flaw in the hard coating on the valve, they don't usually fail at the keeper.  


I should also mention my bike pops (backfires) all the time on deceleration.  It really depends on what map you are running.  I'm running the Jay Marmont map, but I'm planning on adding fuel to the bottom of the map to see if it helps.  

Edited by luckyguy19

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