Adventure Bike Rider Forum

got around to a cbr300r engine transplant ...at the moment its living and beathing sounds sweet ..thats all im up to testing next week

.. ..40percent more braap should be handy (thumbs)


DSC_0196 by minkyhead56, on Flickr[/img]

minkyhead wrote:got around to a cbr300r engine transplant ...at the moment its living and beathing sounds sweet ..thats all im up to testing next week

.. ..40percent more braap should be handy (thumbs)


DSC_0196 by minkyhead56, on Flickr[/img]

Good job, I hope it works out well for you.
I know there are times the 250 needs just a little more oomph to keep up with traffic, but it's so smooth and controlled at low speeds, I really wouldn't want to mess with it.

Does the CBR 300 manage with the same dinky radiator as the CRF250L? or will you need something bigger?
40% more Braap could mean 40% more heat to disperse...

your right ..im not the fist to do this and there arnt any adverse comments on cooling ..the rads look much the same size and the coolant is the same 1.2 litres ..

ill be testing it out it has a coolant light and i have a trailtech temp guage fitted so fingers crossed

Interesting stuff be great to have a read of what you've had to do for the transplant, sounds great ,

Spadger wrote:Interesting stuff be great to have a read of what you've had to do for the transplant, sounds great ,

thanks ill get around to it after testing ...interesting touque figures 60/65 percent more lower down ..that should be good on a trail bike

i was undecided weather to put the 250 box in but having spent hours on gear commader ive decided to stay with the300r box as the ratios are lower 1to three and top speed of 106 mph is not going to apply on the crf

i looked at a few videos before giving it a go ..anyone with a crf will know this aint gonna hapen ,,it wont rev out in fifth let alone 6th

..ignore the nutcase ..but it gives a idea of the lift

i would think it would will criise at 70/75 and will be pretty nippy lower down

im bound to hit a few speedbumps along the way but the engne 300throttle body and ecu are up and running



DSC_0200 by minkyhead56, on Flickr[/img]

Slow and steady wins the race ..... my arse !!
When we going testing ???

Ace job Steve . Can't wait to see it

nethen1 wrote:Slow and steady wins the race ..... my arse !!
When we going testing ???

Ace job Steve . Can't wait to see it

you know i luv me little crf dave ..its all about the real world now ..but early signs are good ..the touque figures and gear commader stuff looks in the park so im very excited

engine was advertised as 1900 miles old and as new ..theres nowt making me doubt that at the moment and it retains its 8000 miles intervals but ill halve that at least

ride next week ?? braaaaap (thumbs)

Daft question...but rather than swap the whole engine wouldnt the too end have dropped straight on ?...like we used ti do with the yam250/350 lc conversions...after all its only 50cc bigger ...

Would have been easier me.thinks..

Does it all fit Minky? I had enough trouble getting another 250 engine back in the frame.

Wonder how long before you're tempted by the 350 conversion :laugh:

Tramp wrote:Daft question...but rather than swap the whole engine wouldnt the too end have dropped straight on ?...like we used ti do with the yam250/350 lc conversions...after all its only 50cc bigger ...

Would have been easier me.thinks..

no i dont believe so ..its not that simple ..your then left with feuling and ecu issues ..no one told the ecu you changed the head ..it has alonger stroke so obviusly conrod is diffrent too and adapting thottle bodies to deliver witha fuel controler or power commader and dyno run everything map wise will need dragging and dropping on a pc/dyno

reliability of kits is patchy from what i read

..the engine drops straight in perfect fit main differences in the head and cam profiles and stroke ..all thats needed is wiring extensions and some loom plugs swapping over
300 ecu and larger 300 throtlle body just fits ...
i wanted a honda engine as made by honda retaining the sevice intervals

its not so hard to swap the motor crf is a easy to work on .. out to in around 5 hours plus a couple sorting out the wiring plus i have the crf motor to sell so i may end up costing me nothing at all.. save a exhaust header gasket and some solder (thumbs)