breaking in my new 08 yz450f

5 replies to this topic
  • mcduffey707

Posted December 27, 2010 - 05:17 AM


Hi i was wondering has anybody ever broke in the new bike in the cold temp. My dad and my brother told me they dont think its a good idea to break in the bike in the cold weather because they think its bad for the engine and hearing them say that gave me a scare. I live in michigan and its in the 20s and i wanna ride my new yz450 at the indoor tracks. Is it ok to break in the bike in the cold weather or should i just wait till spring.

  • grayracer513

Posted December 27, 2010 - 06:47 AM


It makes no difference, really. But, you might want to tape over one radiator to help it reach full coolant temperature.

  • davcon

Posted December 27, 2010 - 06:55 AM


The manual doesn't mention any concerns regarding cold weather break-in.
A new bike will generally run hotter than normal due to the tighter tolerances of new parts. Cool weather would actually help to dissipate the heat. However, make sure its jetted properly. Stock, It would be running lean in cold weather. I believe the stock main jet is a 160. On my bike, with a 160, it runs a bit lean at my altitude of 6000 and 40 degrees outside temp. Not sure of your location but say 1500' at 20 degrees the correction calcs to a 170 main.

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  • mcduffey707

Posted December 27, 2010 - 08:12 AM


Ok sweet and do you think it would be allright to break in the bike while just putting it on the stand and leaving the rear off the ground and running the bike..

  • YamaLink

Posted December 27, 2010 - 08:33 AM


You want to break the bike in while running it hard to seat the rings and seals. My dad did the "break in" while letting a very modded YZF run the entire 2 hour drive to the desert. I am still laughing about that. Can't hurt though.

  • grayracer513

Posted December 27, 2010 - 09:17 AM


The concern I have, and the reason I suggested the tape, is that the 2010 EFI has been guilty of running pretty rich when the coolant temps stay low due to cold weather. Fouling the oil with gas during break in would be worrisome to me. We aren't dealing specifically with an EFI bike here, but still, things work better at real normal operating temps than in the cold.

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