Another 2010 yz450f bogging thread.

3 replies to this topic
  • leo 450yfz

Posted May 20, 2014 - 04:27 PM


Hello everyone.


 Apologies for my first thread being about this! I did search and I did try a bunch of things. Changed my fuel pump and the filter and just replaced the injector. Bike is still bogging, I am thinking about taking the tank apart again and throwing the old OEM pump in, but keeping the new filter,  and if that doesn't help. Trying to maybe replace the head gasket, I'm running out of ideas though and would like to hear some from you.


 Here is how it started and went wrong: I bought the bike used about a month ago. It had 80 hours on the motor, 10 on the complete rebuild (hot rods crank, wisceco piston standard compression, and all the bearings), it wasn't rebuild due to a failure, I suspect the guys family just had money to spend, seeing how the gave me the box of all the old parts from the motor, that are in immaculate condition. The bike ran perfectly fine for the first 2-3 hours after I bought it, given I am still not used to this 450, so I chugged it around a lot in the middle/bottom of the gears. Then I layed it down on a wet day in the grass, it still ran fine after. Then after another hour or 2 it started bogging out on me, like the old carburated bikes did when the pilot was too rich, Then it started stalling even when idling after less that a minute. First thing I did, was change the pump and the filter. Then changed my oil and it smelled a little like gas, and had a little bit of silver flakes in it. So I figured maybe it was the leaking injector, changed that. Still nothing. 


 The radiator doesn't have any oil in the coolant, but it was just a little bit (maybe an 8th) low, when I checked it, so I am not ruling out the head gasket failure. Also wondering, if the piston possibly wasn't completely done being broken in, and if I warped the rings... although after 10 hours of run time after the rebuild, I don't find it likely.


 Anyways, tomorrow I will be trying the pump and the gasket again, but in the meantime I wanted to pick your brains for ideas, I'm trying to get out to the sand dunes for the memorial day weekend and would really hate to miss it.


 Thanks in advance for any kind of advice, and thank you for your time. Sorry about the wall of text!!!


Edit: One last thing, I pulled the plug and it was a little damp (possibly from excessive kicking) and black, but not the fouled up black, just what you'd expect from a normal burn. I'll also be checking the valves and the timing tomorrow, wondering if the chain maybe jumped a tooth, when the bike fell.


Good to be here.



Edited by leo 450yfz, May 20, 2014 - 04:42 PM.

  • leo 450yfz

Posted May 21, 2014 - 07:48 PM


Got it figured out today. Delete the thread if you will please. I know there are plenty of them to go around lol

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  • drtrcr400

Posted May 21, 2014 - 08:44 PM


Got it figured out today. Delete the thread if you will please. I know there are plenty of them to go around lol

So what was the problem? Sometimes these threads are very helpful to people out there who are struggling with similar problems.

  • leo 450yfz

Posted May 21, 2014 - 09:17 PM


So what was the problem? Sometimes these threads are very helpful to people out there who are struggling with similar problems.


 Fair enough, it's actually kind of ridiculous: I did have a leaky injector, that's how I got a bit of gas in my oil. It didn't solve my main issue though. I guess when I wiped out, by throttle cable managed to get bound up just a hair, to where I had no free play in the twist, it was constantly open, but only a tiny bit so it was hard for anyone to notice, it just sounded like high idle, so I dropped the idle down 3 clicks (did it without thinking about it much and completely forgot it, till today)... And that's when my problems started.


 As soon as I realized that there was no free play and adjusted it, my idle turned out to be too low so it kept causing the bikes to stall. turned it back up and my problems were solved, embarrassing really, but hey, if it saves anyone time and 200 bucks worth of parts, I guess it's worth posting lol.  

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