Engine Swap for CRF250L to 450X
  • Dreigh_Ban
    Posts: 6
    Joined: Thu Dec 28, 2017 1:33 am

    Engine Swap for CRF250L to 450X

    by Dreigh_Ban » Thu Dec 28, 2017 1:40 am

    I've been looking around the internet for about 2 hours now and finally decided to ask here. i know that it is possible to swap the CRF250L's engine with relative ease with the CBR500R's, but i would rather swap my engine to the CRF450X's engine but have found nothing on that. if anyone could be of any assistance that would be greatly appreciated.
  • Back2-2
    Posts: 650
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: Engine Swap for CRF250L to 450X

    by Back2-2 » Thu Dec 28, 2017 6:59 am

    Hello and welcome. Anything can be accomplished with enough engineering and determination. ;)
    I think the question is more as to why a 450X engine in a 250L chassis that is really more road use related. The 450X is really not a good road engine. It runs very hot and has to have air flow on the radiators to keep temps in check. You can add fans but the 450 really is by far happiest in off road uses. It has a close ratio transmission that is geared for off road uses. It is like putting a high strung racing engine in a Toyota Corolla --- why would you. That said, if it's your dream to do it than it certainly can be done. Get out the torch and saw and start cutting and welding. :shock:
    Neil
    Scottsdale, AZ
    "It's all about motorbikes - Always has been, always will be"
  • Dreigh_Ban
    Posts: 6
    Joined: Thu Dec 28, 2017 1:33 am

    Re: Engine Swap for CRF250L to 450X

    by Dreigh_Ban » Thu Dec 28, 2017 10:16 pm

    Hello and welcome. Anything can be accomplished with enough engineering and determination. ;)
    I think the question is more as to why a 450X engine in a 250L chassis that is really more road use related. The 450X is really not a good road engine. It runs very hot and has to have air flow on the radiators to keep temps in check. You can add fans but the 450 really is by far happiest in off road uses. It has a close ratio transmission that is geared for off road uses. It is like putting a high strung racing engine in a Toyota Corolla --- why would you. That said, if it's your dream to do it than it certainly can be done. Get out the torch and saw and start cutting and welding. :shock:
    well with that in mind, what would be the best swap that would give me the most power without having to replace the frame. i would be fine replacing the rear suspension, but am not too keen on the forks
  • Back2-2
    Posts: 650
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: Engine Swap for CRF250L to 450X

    by Back2-2 » Fri Dec 29, 2017 6:27 am

    If it was me I would just consider changing bikes to what you want.
    But if you feel the change to "with relative ease with the CBR500R's" then that would be the direction to go. The CBR500 engine in that 250L frame would give you all the power you want. I don't think the results would handle very well with the much higher CG of the 500 engine in the 250L frame but it certainly be powerful. The suspension would need to be reworked for the additional weight also. The brakes on the 250L would be far less than the required for the weight and speeds of the 500 engine.

    I recommend rethinking what you wish to achieve and what bike it original configuration will achieve that goal. There is an incredible amount of engineering that goes into each of the models. You will be happier with a bike that someone else has worked the bugs and glitches out of then dealing with the problems trying to invent your own model. Resale of a chopped up bike it another problem.
    Neil
    Scottsdale, AZ
    "It's all about motorbikes - Always has been, always will be"
  • Dreigh_Ban
    Posts: 6
    Joined: Thu Dec 28, 2017 1:33 am

    Re: Engine Swap for CRF250L to 450X

    by Dreigh_Ban » Sat Dec 30, 2017 4:36 pm

    If it was me I would just consider changing bikes to what you want.
    But if you feel the change to "with relative ease with the CBR500R's" then that would be the direction to go. The CBR500 engine in that 250L frame would give you all the power you want. I don't think the results would handle very well with the much higher CG of the 500 engine in the 250L frame but it certainly be powerful. The suspension would need to be reworked for the additional weight also. The brakes on the 250L would be far less than the required for the weight and speeds of the 500 engine.

    I recommend rethinking what you wish to achieve and what bike it original configuration will achieve that goal. There is an incredible amount of engineering that goes into each of the models. You will be happier with a bike that someone else has worked the bugs and glitches out of then dealing with the problems trying to invent your own model. Resale of a chopped up bike it another problem.
    I do believe you're correct. I would be more happy with a bike that have everything worked out
  • JBD319
    Posts: 2
    Joined: Tue May 29, 2018 10:50 am

    Re: Engine Swap for CRF250L to 450X

    by JBD319 » Wed Jun 13, 2018 9:46 am

    I feel like, with several kit options, your best bet would be to just do a 305cc big bore kit? They're relatively inexpensive, and don't require the serious modifications that a major engine swap would. You'd get a significant boost in power while still having mild and friendly delivery, and not need major suspension or brake upgrades. Just my two cents.
  • edgrrr
    Posts: 2
    Joined: Fri Jan 29, 2010 7:33 am

    Re: Engine Swap for CRF250L to 450X

    by edgrrr » Mon Sep 17, 2018 5:00 pm

    Has anyone swapped a CRF250R engine into the CRF250L frame? I have an absolutely built CRF250R big bore but do not ride much anymore. I would like to make a supermoto but I cannot plate a dirt VIN frame. I can get a good deal on a dropped CRF250L frame, sell the engine, and swap as much of my big bore over.

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