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All 650Rs MY20 CB650R needs new engine, will MY21 work?

creef14

2020
CB650R
Jun 17, 2020
VA, USA
Riding Since
1992
So my 2020 CB650R threw a rod through the bottom of the crankcase...a lot to unpack there but nevertheless, I have found a 2021 CB650R motor that is guaranteed to run.

can anyone think of anything that would prevent me from installing it? Will the euro5 have any effect on the current ECU being from a Euro4 gen bike? Any suggestions or tips are welcome as I look to get this bike back up and running.

TIA!
 

Motojack

2021
CBR650R
May 26, 2019
Check the likes of an online part supplier and checkn if the part number is the same between both years. That's what I would
Do first. Might be cheaper than purchasing an engine for spare parts which is what it sounds like you are thinking about?
 

miweber929

2014
CBR650F
650 Alumnus
Staff
Feb 13, 2015
Woodbury, MN
Riding Since
1975
Check the likes of an online part supplier and checkn if the part number is the same between both years. That's what I would
Do first. Might be cheaper than purchasing an engine for spare parts which is what it sounds like you are thinking about?
I would say this is good advice but is only a kind of a helpful check because part numbers change all the time for minor revisions, color changes or even just differentiating the model years.

C @creef14 There shouldn't be anything hugely different, there were only a few minor tweaks to the tuning for Euro 5 but I would do as instructed above and just start comparing things like TPS sensors, throttle bodies, MAP sensor, look for vents, the airbox, etc., including where things are mounted to be sure it's not a change that was undocumented. You may run into some sensors not being right or pins in the wiring harness being moved (that would be another part I would check numbers on) so you really won't know until you get into it. As far as I know no one on this board has put a '21+ motor into an "older" model.
 

creef14

2020
CB650R
Jun 17, 2020
VA, USA
Riding Since
1992
I think I am just going to have to buy the MY21 engine and test fit it piece by piece.....
 

Tony650r

2020
CBR650R
Nov 30, 2021
Riding Since
2006
I think I am just going to have to buy the MY21 engine and test fit it piece by piece.....
If you have a local Honda shop, it usually pays off to spend a little money there on small items, and to make friends with the people at the parts counter. They look at part numbers and diagrams everyday, and if they’re experienced, usually are pretty helpful if they’re not butt-holes. They’re always interacting with the techs, so they can pick their brain as well. Then you hit ‘em with a box of donuts and you’re in for life 😎
 
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