OK so my CBR400RR NC29 engine just blew up; threw a valve... in talking to people it seems this is a fairly common problem for this bike to have... so i'm considering engine alternatives. I would like to swap a 600cc engine in there, and considering there are not a lot of 400cc USA production engines, i'm hoping there is a 600cc engine that goes in. now this list of possible engines do NOT necessary have to bolt right in, if i have to weld on the frame, that is really not tooo big of an issue; i'm mostly interested in what engine has a head that will fit inside the frame, that can be bolted to or mounts made to bolt the rear of the engine in, and that has a solvable fitting-the-air-box adventure.


for starters, i know the following USA production engine will fit:

1) Honda CB-1, 400cc, produced and sold in USA from 1989 to 1990. 45hp



I have heard that a 1991 CBR600 F2 engine will fit. i'd like to know more about this if anyone has info on it - and of course any other engine options!

SpeedyCorky wrote:OK so my CBR400RR NC29 engine just blew up; threw a valve... in talking to people it seems this is a fairly common problem for this bike to have... so i'm considering engine alternatives. I would like to swap a 600cc engine in there, and considering there are not a lot of 400cc USA production engines, i'm hoping there is a 600cc engine that goes in. now this list of possible engines do NOT necessary have to bolt right in, if i have to weld on the frame, that is really not tooo big of an issue; i'm mostly interested in what engine has a head that will fit inside the frame, that can be bolted to or mounts made to bolt the rear of the engine in, and that has a solvable fitting-the-air-box adventure.


for starters, i know the following USA production engine will fit:

1) Honda CB-1, 400cc, produced and sold in USA from 1989 to 1990. 45hp

I have heard that a 1991 CBR600 F2 engine will fit. i'd like to know more about this if anyone has info on it - and of course any other engine options!

Cb-1 engine will fit physically but it's not drop-in, as the top mount is different.

Nothing will drop right in and due to the already over engineered frame on the 29 you will have a lot of cutting and welding to do.
There used to be a guy on here called firebeast he has fitted both 600 and 900 CBR engines into the 29.

ahh so 600cc and 900cc engine have been swapped into a NC29, eh?


ok so the question is exactly which 600 and 900cc engines....... from what make and model bike, and what year ?????

hopefully a new-as-possible, 600cc, USA production motor...



i'mm interested in what has been done, and i'll just copy that project, rather than reinvent the wheel (no need for that i'd think).

Click members
Search - firebeast
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HTH :)

SpeedyCorky wrote:ok so the question is exactly which 600 and 900cc engines....... from what make and model bike, and what year ?????

hopefully a new-as-possible, 600cc, USA production motor...

Ive seen an early blade engine (900cc) fitted to a 29, seen pics also of the 600 conversion.

None of these will drop in without cutting the frame big time...