YZ470...High Compression or Not???

6 replies to this topic
  • Mighty_Whitey

Posted December 21, 2005 - 05:50 PM


Opinions are like......well.........anybody have some good solid opinions on what would be a better choice here.

I just got the cylinder done at Max Power and she is a 469cc now. I can go with a High Compression Wiseco 13:5:1 or a Standard 12:5:1 compression.

I use the bike to race a 30+ Vet series in Southern California and also trail ride. Probably put about 15 hours a week on it.

For fuel.......I do have a high octane (MotoSport 103) gas station pump right around the corner from me.


Either way, she's still a 470! :bonk:


  • 642MX

Posted December 21, 2005 - 06:18 PM


I have a 13.5:1 Wiseco, only a 426 though. I can tell a big difference in bottom end snap and mid range pull with the higher compression. It will run off pump gas without pinging, but I run race fuel anyway. Downsides are that its a hair harder to kick start, it makes the jetting a little picky, and in long hare scrambles it wears me out faster. I'd do it again. :applause:

  • Mighty_Whitey

Posted December 21, 2005 - 08:02 PM


Thanks for the reply. Just curious on the race gas, whuddya run?

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  • kawirider

Posted December 21, 2005 - 09:07 PM


Get it dynoed and let us know how many ponies you got from boreing it out.

  • aford541

Posted December 21, 2005 - 09:20 PM


Have you tried that U-4 or the elf LMS fuel?
I use the elf LMS it works great, I think you should run the 12.5 piston and when you race use the oxygenated fuel and she should last longer.
Although my 05 likes a little richer jetting on the Oxy fuel.

  • CRFThumper

Posted December 22, 2005 - 05:22 AM


We like the u-4 as well!Burns clean,no hint of pinging,and smells sooooo good!
On the pricy side but you get what you pay for i guess.Just be sure you drain the carb after each use!!! :applause:

  • 642MX

Posted December 23, 2005 - 06:52 AM


Thanks for the reply. Just curious on the race gas, whuddya run?

Citgo 110 leaded. :applause:

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