engine swaps

2 replies to this topic
  • rocky1980

Posted December 07, 2014 - 04:41 AM


hi guys i recently rebuilt the top end of my 2003 yz450f after a few glitches she was up and running sweet......untill one day the kick start jammed!!!! i put her in gear and pushed it backward and the kickstart came back up and all was well.

then............. a few days later it did it again so i rolled the bike back then the kick start came back up so i kicked her off only this time it kicked back smashing my crankcase disaster.

i couldn't find any parts at all in the uk so iv had the case welded up whilst its off i thought ill fit a new cam chain as i removed the flywheel i noticed that someone in the past has had this off and a washer has been pulled inside before the flywheel was fitted and its been smashing the flywheel up so now the flywheel looks a mess inside so luckily  iv managed to order another one.(how it still run is anyones guess) 

I'm sick to the back teeth of this bike its cost more money than its worth.


my question is will a yzf250 2 stroke motor fit in my frame? or are they different mounts etc.


cheers fellas 

Edited by rocky1980, December 07, 2014 - 04:46 AM.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted December 07, 2014 - 08:03 AM



my question is will a yzf250 2 stroke motor fit in my frame? or are they different mounts etc.



Not without cutting and welding.  The front of the frame has to be modified to accommodate the exhaust.  The end product would be a rather overweight 250, most likely.

  • rocky1980

Posted December 07, 2014 - 09:58 AM


bugger oh well looks like ill have to just repair this motor :/ thanks gray

Related Content


Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies

BIGBORE FOR YZ450F 2006? by Taattie94

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.