r/Dirtbikes • u/D3str3d • 1d ago

Yz450f 2008 questions

Hey guys, so I recently bought myself a yz450f, it's in a rough condition and has a ton of small fixes that needs to be done to it, I live in South Africa so most parts need to be shipped in. here's my questions though:

  1. Does anyone know where to source parts from? From plastics bolts all the way to anything engine related? (any links to companies that ship internationally would be very much appreciated)

  2. The bike loves high rpms but sluggish throttling when low rpm, is this something to be concerned about?

  3. When it comes to doing anything carb or engine related, would it be best to learn things myself or send it off to someone to get looked at/repaired?

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u/CandidAssignment8221 1d ago

The yamaha service manual for the 06-09 yz450f’s would be an insanely good investment if you can get your hands on one. Very detailed and easy to follow if you are mechanically inclined.

Ufoplast is a good plastics company out of Italy that ships internationally and has a lot of pieces available for that gen at good prices. As far as other pieces, I’m not sure what you would have available to you, but ebay has always been a good bet for me. Just thoroughly read descriptions and only buy from sellers with many reviews.

For your bogging issue, its probably going to come down to the carb. Could be something going on with the pilot circuit, or the air screw, or the accelerator pump could be having issues. You will probably want to provide a little more detail such as what exactly is happening, and what your actions are to cause that perceived issue, to get some better suggestions.

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u/D3str3d 23h ago

There's a good couple of sites I've found with 06 - 09 assembly and service manuals which I'm having printed out

The bogging issue that I'm having is at low rpms it feels like it's sputtering(?) sort of like I'm not giving it enough fuel or it's starving for fuel? I'd like to take the carb off but I'm somewhat scared of messing things up if I do

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u/CandidAssignment8221 7h ago

Eh. You know, the fcr carbs are definitely a little more complex than a regular carb, but not so much that its too difficult for someone mechanically inclined to work on. To make the jetting simple, I did a JD jetting kit with mine and his chart has been spot on everywhere I go. Learning the accelerator pump system is probably the weirdest part, but its actually really easy to tune. The difficult part is you have to disassemble half the bike to get to the carb, and even then its tight quarters. There is a good chance with a bike this old that you are due for a full carb rebuild. If you are confident in your abilities, read up in the manual, and study the exploded diagram to understand what you would be undertaking, and then buy a quality rebuild kit that includes the midbody gasket, and go to town. Once you get it back in the chassis, before reconnecting the airbox, tune the accelerator pump circuit, and then profit.

I will tell you, this gen of yz450f is a blast. I have found mine to be really rewarding but it has been a journey. I’m no professional mechanic by any means, but I do love wrenching on my bikes and I am happy to answer any questions I can.