2008 yz450f big bore kit HP rates?

Just wondering if anyone has any info on what a big bore kit will do for a 2008 yz450f, im thinking about doing one over the winter to get some more power on the cheap as opposed to the whole head work, cams etc. I currently have a DRD full system and rejetted carb, but looking for more Ummph while going down the straights getting blown by the new 09 hondas while racing supermoto like im standing still. need some more power and not a new bike. any thoughts as to what size bb - no stroker though. I want to keep it simple.

470 is a 4% increase, and will yield about 2-3% more power.

  • Bore the carb
  • Port the head (have an experienced pro do this. It' esay to screw it up.
  • Swap cams

Call Ron Hamp or go with This Route

You'll get lots more than with a big bore.

Just wondering if anyone has any info on what a big bore kit will do for a 2008 yz450f, im thinking about doing one over the winter to get some more power on the cheap as opposed to the whole head work, cams etc. I currently have a DRD full system and rejetted carb, but looking for more Ummph while going down the straights getting blown by the new 09 hondas while racing supermoto like im standing still. need some more power and not a new bike. any thoughts as to what size bb - no stroker though. I want to keep it simple.

I have bored a few yammies and found that cams are the best bang for the buck. Unless the top end is ready to be freshened up I would not change things. Get on the gas sooner and losing some weight (if you are like me) is a better solution. :worthy:

bigger rear sproket help alot.

Get on the gas sooner and losing some weight (if you are like me) is a better solution. :worthy:
bigger rear sproket help alot.

You guys appear to have missed the part about Super Moto.

Can you send your bike or engine to GRAVES :worthy:

You guys appear to have missed the part about Super Moto.

Nope..... I didn't miss that he is a supermoto'er. Unless you are pro, small changes like that make less sense then improving your skills and woking out. Even on the road, but more exagerated on dirt.

Nope..... I didn't miss that he is a supermoto'er. Unless you are pro, small changes like that make less sense then improving your skills and woking out. Even on the road, but more exagerated on dirt.

Sorry the 450's have enough power does not translate to supermoto. Even a novice rider can benefit from a power increase. Trust me I am 240+ on a stock 450. I have carried more corner speed and gotten a better drive out of corners only to be passed back by some lightweight on a 60hp 450 on the following straightaway. All the other things help also skills, fitness even gearing and bike setup but motor also plays a roll.

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